# 24. Automating AMPS With Actions

AMPS provides the ability to run scheduled tasks or respond to events, such as Linux signals, using the Actions interface.

To create an action, you add an `Actions` section to the AMPS configuration file. Each `Action` contains one (or more) `On` statement which specifies when the action occurs, and one (or more) `Do` statement which specifies what the AMPS server does for the action. Within an action, AMPS performs each `Do` statement in the order in which they appear in the file.

AMPS actions may require the use of parameters. AMPS allows you to use variables in the parameters of an action. You can access these variables using the following syntax:

`{{VARIABLE_NAME}}`

AMPS defines a set of default variables when running an action. The event, or a previous action, can add variables in the context of the action. Those variables can be expanded in subsequent parameters. If a variable is used that isn’t defined at the point where it is used, AMPS will expand that variable to an empty string literal. The context can also be updated as the module is running, so any variables that are available at any given point in the file depend on what action was previously executed.

By default, AMPS loads the following variables when it initializes an AMPS action:

Default context variables
Variable | Description
--- | ---
`AMPS_INSTANCE_NAME` | The name of the AMPS instance.
`AMPS_BYTE_XX` | Insert byte XX, where XX is a 2-digit uppercase hex number (00-FF). AMPS expands this variable to the corresponding byte value. These variables are useful for creating field separators or producing characters that are not permitted within XML.
`AMPS_DATETIME` | The current date and time in ISO-8601 format.
`AMPS_UNIX_TIMESTAMP` | The current date and time as a UNIX timestamp.

An example to echo a message when AMPS starts up is shown below. Note the AMPS_INSTANCE_NAME is one of the variables that AMPS pushes to the context when an action is loaded.

    <Actions>
        <Action>
            <On>
                <Module>amps-action-on-startup</Module>
            </On>
            <Do>
                <Module>amps-action-do-echo-message</Module>
                <Options>
                    <Message>instance={{AMPS_INSTANCE_NAME}}</Message>
                </Options>
            </Do>
        </Action>
    </Actions>

AMPS actions are implemented as AMPS modules. To run each statement, AMPS simply calls the module that implements that `Do` statement. The module is free to take any necessary actions. If a `Do` statement returns a failure, AMPS does not run subsequent `Do` statements in that action. This is intended to help make maintenance processes reliable. For example, if a `Do` statement that is intended to copy a log file to a storage directory fails because the device that holds the storage directory is not mounted, further steps in the action – which might do things like remove the log file from the original directory – should not be run. Likewise, if AMPS exits unexpectedly during a given `Do` statement, subsequent statements will not be run.

AMPS provides the modules described in the following sections by default.

## Configuration for Actions

This section lists configuration parameters for AMPS actions.

### On Element: When an Action Runs

This section describes the options for configuring when AMPS runs a given action.

#### Running an Action on a Schedule

AMPS provides the `amps-action-on-schedule` module for running actions on a specified schedule.

The options provided to the module define the schedule on which AMPS will run the actions in the `Do` element.

Parameters for Scheduling Actions
Parameter | Description
--- | ---
Every | Specifies a recurring action that runs whenever the time matches the provided specification. Specifications can take three forms: 1. Timer action - a specification that is simply a duration, such as `4h` or `1d`, creates a timer action. AMPS starts the timer when the instance starts. When the timer expires, AMPS runs the action and resets the timer. 2. Daily action - a specification that is a time of day, such as `00:32` or `17:47`, creates a daily action. AMPS runs the action every day at the specified time. AMPS uses a 24 hour notation for daily actions. 3. Weekly action - a specification that includes a day of the week and a time, such as `Saturday at 11:00` or `Wednesday at 03:32`, creates a weekly action. AMPS runs the action each week on the day specified, at the time specified. AMPS uses a 24 hour notation for weekly actions. AMPS accepts both local time and UTC for time specifications. To use UTC, append a `Z` to the time specifier. For example, the time specification `11:32` is 11:32 AM local time. The time specification `11:32Z` is 11:32 AM UTC.
`Name` | The name of the schedule. This name appears in log messages related to this schedule. Default: `unknown`

This module does not add any variables to the AMPS context.

#### Running an Action in Response to a Signal

AMPS provides the `amps-action-on-signal` module for running actions when AMPS receives a specified signal.

The module requires the `Signal` parameter:

Parameters for Responding to Signals
Parameter | Description
--- | ---
Signal | Specifies the signal to respond to. This module supports the standard Linux signals. Configuring an action uses the standard name of the signal. For example, to configure an action to `SIGUSR1`, the value for the `Signal` element is `SIGUSR1`. To configure an action for `SIGHUP`, the value for the `Signal` element is `SIGHUP` and so on. AMPS reserves `SIGQUIT` for producing minidumps and does not allow this module to override `SIGQUIT`. AMPS registers actions for several signals by default. See Default Signal Actions for details.

This module does not add any variables to the AMPS context.

Caution

Actions can be used to override the default signal behavior for AMPS.

#### Default Signal Actions

By default, AMPS registers the following actions for signals:

Default signal handling actions
On Event | Action
--- | ---
`SIGUSR1` | `amps-action-do-disable-authentication`
`SIGUSR1` | `amps-action-do-disable-entitlement`
`SIGUSR2` | `amps-action-do-enable-authentication`
`SIGUSR2` | `amps-action-do-enable-entitlement`
`SIGINT` | `amps-action-do-shutdown`
`SIGTERM` | `amps-action-do-shutdown`
`SIGHUP` | `amps-action-do-shutdown`

The actions in the table above can be overridden by creating an explicit action in the configuration file.

AMPS reserves the `SIGQUIT` signal and does not allow the configuration file to override the action taken in response to `SIGQUIT`.

Reserved signal
On Event | Action
--- | ---
`SIGQUIT` | `amps-action-do-minidump`

#### Running an Action in Response to an HTTP Request

AMPS includes a module that allows you to configure an action to run when a specified resource underneath the `/amps/administrator/actions` path in the admin interface is requested. The `amps-action-on-admin` module allows you to add a custom action to the admin interface and provides the ability to pass parameters into the `Do` step of those actions using query parameters in the HTTP request.

The module requires the `Path` parameter, which specifies the path under `/amps/administrator/actions` where this action should appear:

Required parameters for ``amps-action-on-admin``
Parameter | Description
--- | ---
Path | Specifies the path under `/amps/administrator/actions` where this action should appear. The action will run when a request for the specified path is received by the AMPS admin interface. For entitlement purposes, the AMPS admin interface treats actions configured using this module identically to resources provided by AMPS. That is, the user requesting that the action run must have access to the appropriate admin resource for the action to run. For example, to add an action that runs journal maintenance at the path `/amps/administrator/actions/journal_cleanup`, you would use the following `Path` element:
    <Path>journal_cleanup</Path>
The `Path` element should contain only a resource name. No `/` character should appear in the `Path` element.

Any query parameters provided as part of the request are added to the context before the `Do` steps for the action are run. This module adds the names and values of the query parameters without adjusting the case of the items.

For some actions, it’s important that a specific context value is present before the action runs. You can configure the module to require that the request provide one or more query parameters using the `RequiredParameter` option to the module. When one or more `RequiredParameter` is specified, the admin console will refuse any request for the resource that does not include all of the required parameters.

The action also provides support for a `Name` element and a `Description` element, which can be used to help tools that monitor or manage AMPS (such as the Galvanometer monitoring tool included with AMPS) provide information on the action.

Optional parameters for ``amps-action-on-admin``
Optional Element | Description
--- | ---
`RequiredParameter` | Specifies that a request to run this action must include the specified query parameter. If the request does not include this item as part of the query parameters, the request will return an error rather than executing the action.
`Name` | Specifies the name to use for display purposes for this resource.
`Description` | Specifies a description to use for display purposes for this resource.

For an example of configuring an action using this module, see Archive Transaction Log Journal Files Older Than A Specified Age In Response to Admin Request.

Tip

The `amps-action-on-admin` module should be used for ad hoc maintenance (such as responding to an unexpected increase in traffic by archiving journals ahead of schedule) or tasks that are triggered unpredictably by an external system. For tasks that need to run on a regular basis or frequently (for example, every few seconds), `amps-action-on-schedule` is more efficient.

#### Running an Action on Startup or Shutdown

AMPS includes modules to run actions when AMPS starts up or shuts down.

The `amps-action-on-startup` module runs actions as the last step in the startup sequence. The `amps-action-on-shutdown` module runs actions as the first step in the AMPS shutdown sequence.

In both cases, actions run in the order that the actions appear in the configuration file.

These modules do not require any parameters.

These modules do not add any variables to the AMPS context.

#### Running an Action on Client Logon

AMPS provides the `amps-action-on-logon-client` module for running actions when a user logs into an AMPS client.

This module does not require any parameters.

This module adds the following variables to the AMPS context:

Context Variables for On Client Logon
Variable | Description
--- | ---
`AMPS_CLIENT_NAME` | The name of the AMPS client.
`AMPS_CONNECTION_NAME` | The name of the AMPS connection.
`AMPS_AUTHENTICATION_ID` | The authentication ID of the AMPS connection.

#### Running an Action on Client Connection

AMPS provides modules for running actions on the connection or disconnection of an AMPS client.

The `amps-action-on-disconnect-client` runs actions once an AMPS client instance disconnects. The `amps-action-on-connect-client` runs actions once an instance of an AMPS client successfully connects.

These modules require no parameters.

These modules add the following variables to the AMPS context:

Context Variables for On Connect and Disconnect Client
Variable | Description
--- | ---
`AMPS_CLIENT_NAME` | The name of the AMPS client. (For the `amps-action-on-connect-client` action, this will be the connection name since this event happens before the client has provided a client name in the logon command.)
`AMPS_CONNECTION_NAME` | The name of the AMPS connection.
`AMPS_AUTHENTICATION_ID` | The authentication ID of the AMPS connection (for `amps-action-on-disconnect-client` action only).

#### Running an Action in Response to Outgoing Replication Connections

AMPS includes a set of modules that allow you to configure an action to run based on events for outgoing replication connections.

The `amps-action-on-connect-replication` module runs when an outgoing `Destination` is connected. The `amps-action-on-disconnect-replication` module runs when an outgoing `Destination` is disconnected.

The `amps-action-on-replication-resync-complete` module runs when a `Destination` has been brought up to date with the transaction log of the local instance.

The `amps-action-on-upgrade-replication` module runs when an outgoing replication connection that has been previously downgraded to acknowledge messages `async` is upgraded to acknowledge messages `sync`.

The `amps-action-on-downgrade-replication` module runs when an outgoing replication connection that is configured to acknowledge messages `sync` has been downgraded to acknowledge messages `async`.

These modules require no parameters.

These modules add the following variables to the AMPS context:

Context Variables for Outgoing Replication Connect and Disconnect
Variable | Description
--- | ---
`AMPS_REPLICATION_PEER_NAME` | The instance name of the AMPS instance on the opposite end of the connection, if available.
`AMPS_REPLICATION_CLIENT_NAME` | The name of the AMPS client used for this connection.
`AMPS_REPLICATION_REMOTE_ADDRESS` | The remote address of the opposite end of the connection.
`AMPS_REPLICATION_GROUP_NAME` | The group name of the AMPS instance on the opposite end of the connection, if available.
`AMPS_REPLICATION_TRANSPORT_NAME` | The name of the transport making the outgoing connection.

#### Running an Action in Response to Incoming Replication Connections

AMPS includes a set of modules that allow you to configure an action to run based on events for incoming replication connections.

The `amps-action-on-connect-incoming-replication` module runs when an incoming replication connection is accepted. The `amps-action-on-disconnect-incoming-replication` module runs when an incoming replication connection is disconnected.

These modules require no parameters.

These modules add the following variables to the AMPS context:

Context Variables for Incoming replication Connect and Disconnect
Variable | Description
--- | ---
`AMPS_REPLICATION_PEER_NAME` | The instance name of the AMPS instance on the opposite end of the connection, if available.
`AMPS_REPLICATION_CLIENT_NAME` | The name of the AMPS client used for this connection.
`AMPS_REPLICATION_REMOTE_ADDRESS` | The remote address of the opposite end of the connection.
`AMPS_REPLICATION_GROUP_NAME` | The group name of the AMPS instance on the opposite end of the connection, if available.

#### Running an Action on Subscribe or Unsubscribe

AMPS provides modules for running actions when a client subscribes or unsubscribes.

The `amps-action-on-subscribe` runs actions when an AMPS client enters a subscription command. The `amps-action-on-unsubscribe` runs actions when an AMPS client unsubscribes (either by sending an explicit unsubscribe command or by disconnecting).

These modules require the following parameters:

Parameters for On Connect and Disconnect Client
Parameter | Description
--- | ---
Topic | Specifies the topic or topic regular expression pattern to monitor for subscribe commands.
MessageType | The message type of the topic to monitor for subscribe or unsubscribe. There is no default for this parameter.

These modules add the following variables to the AMPS context:

Context Variables for On Subscribe and On Unsubscribe
Variable | Description
--- | ---
`AMPS_TOPIC` | The name of the topic specified by the subscribe or unsubscribe command.
`AMPS_CLIENT_NAME` | The name of the client submitting the command.
`AMPS_OPTIONS` | The options on the subscription.
`AMPS_FILTER` | The filter for the subscription.

#### Running an Action on Message Delivery

AMPS provides modules to run actions when AMPS delivers a message to subscribers. The basic flow of AMPS messaging is to first receive a published message, find the subscriber(s) to which this message will be sent, then deliver the message to the subscriber(s).

The `amps-action-on-deliver-message` runs actions when AMPS delivers a `publish` message to subscribers.

This module requires the `Topic` and the `MessageType` of the message that has been delivered.

Parameters for On Deliver Message
Parameter | Description
--- | ---
Topic | The name of the topic to monitor for message delivery. This parameter supports regular expressions. There is no default for this parameter.
MessageType | The message type of the topic to monitor for message delivery. There is no default for this parameter.

This module adds the following variables to the AMPS context:

Context Variables for On Deliver Message
Variable | Description
--- | ---
`AMPS_TOPIC` | The topic of the message.
`AMPS_DATA` | The data the message contains.
`AMPS_DATA_LENGTH` | The length of the data the message contains.
`AMPS_BOOKMARK` | The bookmark associated with this message. This is an empty string if the message does not have a bookmark.
`AMPS_CLIENT_NAME` | The name of the client to which this message was delivered.
`AMPS_CORRELATION_ID` | The correlation ID set on the publish command, if one was set.

#### Running an Action on Message Publish

AMPS provides modules to run actions when a message is published to AMPS. The basic flow of AMPS messaging is to first receive a published message, find the subscriber(s) to which this message will be sent, then deliver that message to the subscriber(s).

The `amps-action-on-publish-message` runs actions as soon as a message is published to AMPS.

Warning

This action is treated by the AMPS engine as a subscription from an internal AMPS client.

When working with queues, use this action with the underlying topic of the queue rather than the queue topic itself. Because this action creates a subscription, using this action with the queue topic will cause the action to lease messages from the queue even though the action does not acknowledge messages. This means that, when used with the queue topic itself, the action will interfere with other subscribers and depending on the queue configuration, may only receive one message during the lifetime of the instance.

This module requires the `Topic` and the `MessageType` of the message that was published. In addition to that, this module also accepts the optional parameters listed below:

Parameters for On Publish Message
Parameter | Description
--- | ---
Topic | The name of the topic to monitor for publishes. This parameter supports regular expressions. There is no default for this parameter.
MessageType | The message type of the topic to monitor for publishes. There is no default for this parameter.
`MessageSource` | The source to monitor for publishes. The source of the message defaults to `all`, which monitors both publishes directly to this AMPS instance and messages received via replication. This parameter also accepts `local` for when the message source is published directly to this AMPS instance and `replicated` for messages received via replication.
`Filter` | Sets the filter to apply. Only messages that match this filter will cause the action to run.
`Options` | Sets the options to apply when listening for messages. This action supports any option that would be supported by the subscribe command when not using a bookmark.

This module adds the following variables to the AMPS context:

Context Variables for On Publish Message
Variable | Description
--- | ---
`AMPS_TOPIC` | The topic of the message.
`AMPS_DATA` | The data the message contains.
`AMPS_DATA_LENGTH` | The length of the data that the message contains.
`AMPS_BOOKMARK` | The bookmark associated with this message.
`AMPS_TIMESTAMP` | The time at which the message was processed by AMPS.
`AMPS_CLIENT_NAME` | The name of the client from which the message was published.

#### Running an Action on OOF Message

When a record that previously matched a subscription has been updated so that the record no longer matches its subscription, AMPS sends an out-of-focus (OOF) message to let subscribers know that their record no longer matches the subscription. With `amps-action-on-oof-message`, you can enter a subscription within AMPS and run actions when an OOF message for that subscription is produced.

Warning

This action is treated by the AMPS engine as a subscription from an internal AMPS client.

Do not use this action with queue topics. Because this action creates a subscription, using this action with the queue topic will cause the action to lease messages from the queue even though the action does not acknowledge messages. This means that, when used with the queue topic itself, the action will interfere with other subscribers and, depending on the queue configuration, may only receive one message during the lifetime of the instance.

Furthermore, because each publish to a queue topic is treated as a distinct message, a subscription to a queue topic will never produce `oof` messages.

This module requires the `Topic` and the `MessageType` of the OOF message. In addition to that, this module also accepts the optional parameters listed below:

Parameters for On OOF Message
Parameter | Description
--- | ---
Topic | The topic to monitor for OOF messages. The topic specified must be a SOW topic, view or conflated topic. This parameter supports regular expressions. There is no default for this parameter. This module should not be used with queue topics.
MessageType | The message type of the topic to monitor for OOF messages. This parameter supports regular expressions. There is no default for this parameter.
`Filter` | Set the filter to apply. This filter forms the internal subscription for which OOF messages will be generated.
`Type` | The type of OOF message to take action on. `match` - take action on OOF messages generated because message no longer matches filter. `delete` - take action on OOF messages generated because message has been removed from the SOW. `expire` - take action on OOF messages generated because the message expired from the SOW. `all` - take action on all of the above types. Defaults to `all`.

This module adds the following variables to the AMPS context:

Context Variables for On OOF Message
Variable | Description
--- | ---
`AMPS_TOPIC` | The topic of the OOF message.
`AMPS_DATA` | The data of the OOF message.
`AMPS_DATA_LENGTH` | The length of the data of the OOF message.
`AMPS_PREVIOUS_DATA` | The data previously contained from the updated record.
`AMPS_PREVIOUS_DATA_LENGTH` | The length of the data previously contained from the updated record.

#### Running an Action on Affinity Assignment

AMPS includes a module to help with building a message affinitization strategy.

With message affinitization, each record in a SOW Topic can be assigned to a single affinitized client. The `amps-action-on-message-affinity` module handles monitoring the SOW topic and running an action when a key is affinitized or de-affinitized.

A client connection indicates that it wants to participate in affinitization by subscribing to a topic to be used for the assignment metadata, referred to as the “control topic”.

Notice that although this action runs when message affinitization is updated, the `On` step does not, by itself, specify what happens when affinitization is updated. It is up to the Action configuration to take appropriate steps when affinitization is updated.

Tip

This module keeps track of affinitizing messages to processors and runs an action when affinity is assigned or changed. However, it is up to the configuration of the action to manage alerting processors, and it is up to the processors themselves to respond to the alert and adjust their subscriptions accordingly.

This action requires the following parameters. In addition to that, this module also accepts an optional parameter listed below:

Parameter | Description
--- | ---
MessageType | The message type of the monitored topic and the control topic.
ControlTopic | The name of the control topic. This topic is monitored for subscriptions. Any client that subscribes to the `ControlTopic` is considered to be eligible to have messages affinitized to that client.
DataTopic | The name of the topic that contains the messages to be affinitized. Each distinct record in the topic (that is, each distinct SOW Key) will be affinitized. By default, all data within the topic will be affinitized. Optionally, you can restrict affinitization to only certain records (for example, orders in a certain state) by setting the `DataFilter` option.
`DataFilter` | When present, restricts affinitization to only those messages in the `DataTopic` that also match the `DataFilter`.

Parameters for On Message Affinity

This module adds the following variables to the AMPS context:

Variable | Description
--- | ---
`AMPS_DATA` | The data of the message being affinitized.
`AMPS_CLIENT_NAME` | The name of the client the message is being affinitized to or removed from.
`AMPS_AFFINITY_ACTION` | The type of event. If the message is being affinitized to this client, the type will be `assign`. If the message is being de-affinitized, the type will be `unassign`.
`AMPS_AFFINITY_REASON` | The reason for the event. For example, if the message no longer matches the `DataFilter` or has been deleted, the reason would be `oof`. If the update is happening because the client that was assigned to the message is no longer active, the reason would be `unsubscribe`.

Context Variables for On Message Affinity

##### Considerations and Limitations

The `amps-action-on-message-affinity` module has the following considerations for use:

- Affinitization is tracked independently on each instance of AMPS. In a replicated mesh of AMPS instances, each instance independently monitors the `DataTopic` and `ControlTopic`. AMPS does not make any effort to coordinate affinitization across replicated instances.
- The affinitization module relies on the SOW key (or grouping, for affinitization over views) to determine message identity. Therefore, affinitization can only be used for a `Topic`, `RegexTopic`, `View`, or `ConflatedTopic`. Since each message in a `Queue`, `LocalQueue`, or `GroupLocalQueue` is considered to be a distinct message, monitoring one of these topic types for affinitization would not produce useful results (however, if the underlying topic of a queue is maintained as a `Topic` in the SOW, using that `Topic` for affinitization could be useful).

##### Affinitization Configuration Example

The following example shows one way to use the `amps-action-on-message-affinity` module to assign specific symbols to a processor. In this example, a processor would subscribe to the `symbol_processor_assignments` topic to receive the symbols that have been affinitized to that processor. It would then maintain a subscription to the `orders` topic with a filter that limits the subscription to just the symbols that have been provided to the subscriber from the `symbol_processor_assignments` topic.

When a processor receives an event with a symbol and the event `"assign"`, the processor adds the symbol in that event to the list of symbols in the filter for the subscription to the orders topic (typically, using the `replace` option to adjust the existing subscription in place). When a processor receives an event with a symbol and the event `"unassign"`, the processor removes that symbol from the filter for the subscription to the orders topic.

    <Action>
       <On>
         <Module>amps-action-on-message-affinity</Module>
         <Options>
           <MessageType>json</MessageType>
           <DataTopic>symbols</DataTopic>
           <ControlTopic>symbol_processor_assignments</ControlTopic>
         </Options>
       </On>
       <Do>
           <Module>amps-action-do-extract-values</Module>
           <Options>
             <Data>{{AMPS_DATA}}</Data>
            <MessageType>json</MessageType>
             <Value>SYMBOL=/symbol</Value>
           </Options>
       </Do>
       <Do>
         <Module>amps-action-do-publish-message</Module>
         <Options>
           <MessageType>json</MessageType>
           <Topic>symbol_processor_assignments</Topic>
           <Data>{"client_name":"{{AMPS_CLIENT_NAME}}",
                  "symbol":"{{SYMBOL}}",
                  "event":"{{AMPS_AFFINITY_ACTION}}",
                  "reason":"{{AMPS_AFFINITY_REASON}}"}</Data>
         </Options>
       </Do>
       <If>
         <Module>amps-action-if-condition</Module>
         <Options>
            <Condition>"{{AMPS_AFFINITY_ACTION}}" == "unassign"</Condition>
         </Options>
       </If>
       <Do>
         <Module>amps-action-do-delete-sow</Module>
         <Options>
            <Topic>symbol_processor_assignments</Topic>
            <MessageType>json</MessageType>
            <Filter>/symbol = "{{SYMBOL}}"</Filter>
         </Options>
       </Do>
     </Action>

The underlying topics can be defined as needed. For example, the following configuration automatically tracks the set of symbols in an orders topic to be affinitized using the action above:

    <SOW>
      <Topic>
         <Name>orders</Name>
         <MessageType>json</MessageType>
         <Key>/id</Key>
         <FileName>${AMPS_DATA}/sow/%n.sow</FileName>
      </Topic>
      <View>
         <Name>symbols</Name>
         <MessageType>json</MessageType>
         <UnderlyingTopic>orders</UnderlyingTopic>
         <Projection><Field>/symbol</Field></Projection>
         <Grouping><Field>/symbol</Field></Grouping>
       </View>
       <Topic>
          <Name>symbol_processor_assignments</Name>
          <MessageType>json</MessageType>
          <Key>/symbol</Key>
          <Durability>transient</Durability>
      </Topic>
    </SOW>

This action attempts to affinitize new messages so as to keep the overall number of messages roughly balanced across the current processors. If a processor unsubscribes from the `ControlTopic`, messages currently affinitized to that processor will be distributed to other processors. However, messages are not rebalanced among running processors. Once a given SOW Key is affinitized to a processor, it remains affinitized to that processor until the processor unsubscribes, or the record is deleted from the topic.

#### Running an Action on Minidump

AMPS provides the `amps-action-on-minidump` module for running actions when AMPS generates a minidump.

This module does not require parameters.

This module adds the following variable to the AMPS context:

Context Variable for On Minidump
Variable | Description
--- | ---
`AMPS_MINIDUMP_PATH` | The path to where the minidump is created.

#### Running an Action on Offline Start or Stop

AMPS provides modules to run actions when an AMPS client is marked as a slow client and also for when the AMPS client catches up to no longer be subject to slow client offlining.

Slow client offlining is a feature in AMPS that reduces the memory resources consumed by slow clients. More on this feature can be found in Slow Client Management and Capacity Limits.

The `amps-action-on-offline-start` module runs actions as the first step when AMPS’s result set reaches its disk limit and has to disconnect the client. The `amps-action-on-offline-stop` module runs actions as AMPS is no longer subject to slow client offlining.

In both cases, actions run in the order that the actions appear in the configuration file.

Both modules do not require any parameters.

Both modules add the following variables to the AMPS context:

Context Variables for On Offline Start and Stop
Variable | Description
--- | ---
`AMPS_CLIENT_NAME` | The name of the AMPS client.
`AMPS_CONNECTION_NAME` | The name of the AMPS connection.

#### Running an Action on SOW Message Deletion

AMPS provides a module to run an action when a message is deleted from a topic in the SOW.

The `amps-action-on-sow-delete-message` module monitors a topic for deletions from the SOW. The action runs once for each message that is deleted in the matching topic.

This action requires the following parameters:

Parameters for On SOW Message Deletion
Parameter | Description
--- | ---
Topic | The name of the topic to monitor for messages. This parameter does not support regular expressions. The topic name must be either a SOW topic, a view, a conflated topic or a queue. There is no default for this parameter.
MessageType | The message type of the topic to monitor for messages. There is no default for this parameter.

The module adds the following variables to the AMPS context:

Context Variables for On SOW Message Delete
Variable | Description
--- | ---
`AMPS_TOPIC` | The topic of the message that was deleted.
`AMPS_DATA` | The current data of the message.
`AMPS_DATA_LENGTH` | The length of the current data of the message, in bytes.
`AMPS_CORRELATION_ID` | The correlation ID set on the publish command, if one was set.

#### Running an Action on SOW Message Expiration

AMPS provides a module to run an action when a message expires from a topic in the SOW.

The `amps-action-on-sow-expire-message` module monitors a topic for expirations. The action runs once for each message that expires in the matching topic. Notice, in particular, that this includes monitoring messages that expire from the queue, which are presented as SOW expirations to this module.

This action requires the following parameters. In addition to that, this module also accepts an optional parameter listed below:

Parameters for On SOW Message Expiration
Parameter | Description
--- | ---
Topic | The name of the topic to monitor for messages. This parameter does not support regular expressions. The topic name must be either a SOW topic, a view, a conflated topic or a queue. There is no default for this parameter.
MessageType | The message type of the topic to monitor for messages. There is no default for this parameter.
`Reason` | An optional comma-delimited string indicating the expiration reasons to monitor for. For example, setting this to `time_limit,forced_expire` will cause this action to be invoked only when the expiration reason includes one of `time_limit` or `forced_expire`. For more information on the allowed values and definitions, see the documentation for `AMPS_REASON` below.

The module adds the following variables to the AMPS context:

Context Variables for On SOW Message Expire
Variable | Description
--- | ---
`AMPS_TOPIC` | The topic of the message that expired.
`AMPS_DATA` | The current data of the message.
`AMPS_DATA_LENGTH` | The length of the current data of the message, in bytes.
`AMPS_REASON` | A comma-delimited string indicating one or more reason(s) the message was expired. This string contains one or more of the following values: `time_limit` - the expiration time for this message or topic has passed. `forced_expire` - this queue message was acknowledged with an `expire` option resulting in the message’s immediate removal. `max_cancels` - this queue message was acknowledged with a `cancel` option and the number of cancels exceeded the queue’s configured `MaxCancels` limit. `max_deliveries` - this queue message was not successfully acknowledged by a subscriber and the number of deliveries has exceeded the queue’s `MaxDeliveries` limit.
`AMPS_CORRELATION_ID` | The correlation ID set on the publish command if one was set.

#### Running an Action on Message State Change

AMPS provides two modules, `amps-action-on-alert` and `amps-action-on-message-condition-timeout`, to run an action when a message in a SOW topic meets a specific condition for longer than a specified period of time. These modules provide a way to track specific messages in a SOW topic and indicate whether the message has timed out (that is, been in the monitored state longer than expected) or whether the message has been processed as expected and is no longer being tracked within the specified timeout.

The `amps-action-on-alert` action monitors a SOW topic for messages that match a filter and triggers an action when either:

- The message has remained matched on the filter for at least the specified duration (indicating a timeout), or
- An out-of-focus message is received for the message (indicating that the message is no longer tracked)

The `amps-action-on-message-condition-timeout` action monitors a SOW topic for messages that match a filter and triggers an action when:

- The message has remained matched on the filter for at least the specified duration (indicating a timeout)

Use `amps-action-on-message-condition-timeout` if only timeouts are important, otherwise use `amps-action-on-alert` if both timeouts and message tracking are important.

For example, a set of actions might be configured to publish a message to an `Alerts` topic if an order is unprocessed for more than a specified timeout. When the order is processed, the actions might publish a message to a `Statistics` topic for tracking purposes. Rather than creating two independent actions, which could lead to overlap if the order is processed at the same time that the alert is being generated, use this action to guarantee that only one of the events will be generated.

The module tracks each message that matches the filter individually, and will run once for each message tracked.

This module uses the Out-of-Focus notification (OOF) mechanism. When a message matches the specified topic and filter, the module begins tracking that message. If no OOF notification is received for that message within the specified timeout, the action runs for that message and indicates that the timeout has been exceeded. If an OOF notification is received before the timeout expires, then the action runs for that message, indicating that the message is no longer tracked.

This module uses the custom event system as a way of indicating whether a given message was removed from tracking, or whether the message timed out. When configuring the action, you specify the event to raise for each of these states. This module stores the exact event raised in a context variable, which you can then use with `amps-action-do-event` to raise the event.

Caution

While the AMPS server is running, this action will trigger exactly once for each message after it reaches the timeout period. When AMPS restarts, if a message that had previously triggered this action still exists in the SOW topic (and still matches the filter provided, if any), the action will run for that message immediately after the module initializes on restart.

This action requires the following parameters. In addition to that, this module also accepts the optional parameters listed below:

Parameters for On Alert
Parameter | Description
--- | ---
Topic | The name of the topic to monitor for messages. This parameter does not support regular expressions. The topic name must be either a SOW topic, a view or a conflated topic. Queues are not supported. There is no default for this parameter.
MessageType | The message type of the topic to monitor for messages. There is no default for this parameter.
OOFEvent | The value to store when an out-of-focus notification is received for a tracked message. There is no default for this parameter.
TimeoutEvent | The value to store when a message is in the tracked state for longer than the timeout period. There is no default for this parameter.
EventVariable | The name of the context variable in which to store the reason that the action is running (either the string in `OOFEvent` or the string in `TimeoutEvent`). There is no default for this parameter.
`Duration` | The amount of time to wait for an OOF notification for the message before running the action.
`Filter` | Sets the filter to apply. Only messages that match this filter will be monitored by this action. If no filter is provided, every message of the specified message type in topics that match the `Topic` value will be monitored.

The module adds the following variables to the AMPS context:

Context Variables for On Alert
Variable | Description
--- | ---
`AMPS_TOPIC` | The topic of the message that triggered the alert.
`AMPS_DATA` | The current data of the message.
`AMPS_DATA_LENGTH` | The length of the current data of the message, in bytes.
`AMPS_BOOKMARK` | The bookmark of the message. Empty if there is no bookmark for the message.
`AMPS_TIMESTAMP` | The timestamp at which the module began tracking the message.
`AMPS_CLIENT_NAME` | The client name of the current value of the message.
`AMPS_SOW_KEY` | The current SowKey for the message.
The variable specified in `EventVariable` | The reason the action is running. This will be either the value of `OOFEvent` or the value of `TimeoutEvent`, depending on what caused the action to run.

#### Running an Action on Message Condition Timeout

AMPS provides a module to run an action when a message in a SOW topic meets a specific condition for longer than a specified period of time. For example, an action might be configured to publish a message to an `Alerts` topic if an order is unprocessed for more than a specified timeout.

AMPS also provides a module, `amps-action-on-alert`, that runs when either a message has been in a specific condition for a longer than expected period of time, or the module receives an out-of-focus notification indicating that the message no longer meets the tracking condition. Use that module if both conditions are important. Use this module if it is only important to track timeouts.

The `amps-action-on-message-condition-timeout` monitors a SOW topic for messages that match a filter and triggers an action for each message that remains matched on that filter for at least the specified duration.

This module uses the Out-of-Focus notification (OOF) mechanism. When a message matches the specified topic and filter, the module begins tracking that message. If no OOF notification is received for that message within the specified timeout, the action runs for that message.

The module tracks each message that matches the filter individually, and will run once for each message that exceeds the timeout.

Caution

While the AMPS server is running, this action will trigger exactly once for each message after it reaches the timeout period. When AMPS restarts, if a message that had previously triggered this action still exists in the SOW topic (and still matches the filter provided, if any), the action will run for that message immediately after the module initializes on restart.

This action requires the following parameters. In addition to that, this module also accepts the optional parameters listed below:

Parameters for On Message Condition Timeout
Parameter | Description
--- | ---
Topic | The name of the topic to monitor for messages. This parameter does not support regular expressions. The topic name must be either a SOW topic, a view or a conflated topic. Queues are not supported. There is no default for this parameter.
MessageType | The message type of the topic to monitor for messages. There is no default for this parameter.
`Duration` | The amount of time to wait for an OOF notification for the message before running the action.
`Filter` | Sets the filter to apply. Only messages that match this filter will be monitored by this action. If no filter is provided, every message of the specified message type in topics that match the `Topic` value will be monitored.

The module adds the following variables to the AMPS context:

Context Variables for On Message Condition Timeout
Variable | Description
--- | ---
`AMPS_TOPIC` | The topic of the message that triggered the alert.
`AMPS_DATA` | The current data of the message.
`AMPS_DATA_LENGTH` | The length of the current data of the message, in bytes.
`AMPS_BOOKMARK` | The bookmark of the message. Empty if there is no bookmark for the message.
`AMPS_TIMESTAMP` | The timestamp at which the module began tracking the message.
`AMPS_CLIENT_NAME` | The client name of the current value of the message.
`AMPS_SOW_KEY` | The current SowKey for the message.

#### Running an Action on a Custom Event

The AMPS action system provides a way to create custom events and run an action when the custom event is raised. The `amps-action-on-execute-event` action runs when a specified custom event is raised by the `amps-action-do-execute-event` action.

This action takes a single parameter:

Parameters for On Execute Event
Parameter | Description
--- | ---
Event | The value to watch for. When an event with this name is raised, the action runs. There is no default for this parameter.

This module does not add any variables to the AMPS context.

### Do Element: Defining the Action to Take

This section describes the default modules for specifying what AMPS does when an action runs.

#### Rotate Log Files

AMPS provides the following module for rotating log files and loads this module by default:

Managing Logs
Module Name | Does
--- | ---
`amps-action-do-rotate-logs` | Rotates logs that are older than a specified age, for log types that support log rotation. Rotating a log involves closing the log and opening the next log in sequence. AMPS will use the name specifier provided in the AMPS configuration for the new log file. This may overwrite the current log file if the specifier results in the same name as the current log file.

This module does not require options.

This module does not add any variables to the AMPS context.

#### Manage the Statistics Database

AMPS provides the following modules for managing the statistics database. As a maintenance strategy, 60East recommends truncating statistics on a regular basis. This frees space in the database file, which will be reused as new statistics are generated. It is generally not necessary to vacuum statistics unless you have changed your retention policy so that less data is retained between truncation operations. With regular truncation, the statistics database file will usually stabilize at the correct size to hold the amount of data your application generates between truncation operations.

AMPS loads these modules by default.

Managing Statistics
Module Name | Usage
--- | ---
`amps-action-do-truncate-statistics` | Removes statistics that are older than a specified age. This frees space in the statistics file, but does not reduce the size of the file.
`amps-action-do-vacuum-statistics` | Deprecated This action has been deprecated in current versions of AMPS and will no longer vacuum statistics. 60East recommends offline maintenance of the statistics database instead. See the section on the AMPS Statistics Database, in the AMPS User Guide, for details on shrinking the size of a statistics database.

The `amps-action-do-truncate-statistics` module requires an `Age` parameter that specifies the age of the statistics to process.

Parameters for Managing Statistics
Parameter | Description
--- | ---
Age | Specifies the age of the statistics to remove. The module processes any file older than the specified `Age`. For example, when the `Age` is `5d`, the module removes statistics that are older than 5 days. There is no default for this parameter.

These modules do not add any variables to the AMPS context.

#### Manage Journal Files

AMPS provides the following modules for managing journal files and loads these modules by default:

Managing Journals
Module Name | Does
--- | ---
`amps-action-do-archive-journal` | Archives journal files that are older than a specified age to the `JournalArchiveDirectory` specified for the transaction log. This action marks files to be archived and then returns.
`amps-action-do-compress-journal` | Compresses journal files that are older than a specified age. This action marks files to be compressed and then returns.
`amps-action-do-remove-journal` | Deletes journal files that are older than a specified age. This action marks files to be deleted and then returns. If a journal file is currently in use, it will be removed when it is no longer in use.

AMPS will only remove journal files that are no longer needed by the instance. AMPS ensures that all replays from a journal file are complete, all queue messages in that journal file have been delivered (and acknowledged, if required), and all messages from a journal file have been successfully replicated before removing the file.

Journal files that have been compressed or archived (or both) are still part of the transaction log. AMPS will compress and archive journal files that have undelivered queue messages, or that have not yet been fully replicated, and so on.

Each of these modules requires an `Age` parameter that specifies the age of the journal files to process.

Parameters for Managing Journals
Parameter | Description
--- | ---
Age | Specifies the age of files to process. The module processes any file older than the specified `Age`. For example, when the `Age` is `5d`, only files that have not been written to for longer than 5 days will be processed by the module. AMPS does not remove the current journal file or files that are being used for replay, files that are being used for replication or files that contain unacknowledged and unexpired messages in a queue; even if the file is older than the `Age` parameter. AMPS does not allow gaps in the journal files, so it will only remove a given file if all previous files have been removed. AMPS can compress and archive journal files that are still in use since compressed or archived journal files are part of the transaction log and AMPS will replay messages from these files. There is no default for this parameter.

These modules do not add any variables to the AMPS context.

#### Compressing Files

AMPS provides the following module for compressing files. Use this action to compress error log files that are no longer needed. AMPS loads this module by default.

Caution

This action compresses files that match an arbitrary pattern. If the pattern is not specified carefully, this action can compress files that contain important data, are required for AMPS, or are required by the operating system.

Caution

This action cannot be used to safely compress journal files (also known as transaction log files). Use the actions described in Manage Journal Files for these files.

Compressing Files
Module Name | Does
--- | ---
`amps-action-do-compress-files` | Compresses files that match the specified pattern that are older than the specified age. This action accepts an arbitrary pattern, and removes files that match that pattern. While AMPS attempts to protect against deleting journal files, using a pattern that removes files that are critical for AMPS, for the application, or for the operating system may result in loss of data. The module does not recurse into directories. It skips open files. The module does not compress AMPS journals (that is, files that end with a `.journal` extension), and reports an error if a file with that extension matches the specified `Pattern`. The commands to remove files are executed with the current permissions of the AMPS process.

This module requires an `Age` parameter that specifies the age of the files to remove, as determined by the update to the file. This module also requires a `Pattern` parameter that specifies a pattern for locating files to remove.

Parameters for Compressing Files
Parameter | Description
--- | ---
Age | Specifies the age of files to process. The module removes any file older than the specified `Age` that matches the specified `Pattern`. For example, when the `Age` is `5d`, only files that have not been modified within 5 days and that match the pattern will be processed by the module. There is no default for this parameter.
Pattern | Specifies the pattern for files to remove. The module removes any files that match the specified `Pattern` that have not been modified more recently than the specified `Age`. This parameter is interpreted as a Unix shell globbing pattern. It is not interpreted as a regular expression. As with other parameters that use the file system, when the pattern specified is a relative path, the parameter is interpreted relative to the current working directory of the AMPS process. When the pattern specified is an absolute path, AMPS uses the absolute path. There is no default for this parameter.
`Keep` | Specifies the number of files that meet the `Age` and `Pattern` criteria to leave uncompressed. When this parameter is specified, AMPS will compress files matching the criteria, starting with the oldest files, and stop when the number of remaining files is the number specified in this parameter. There is no default for this parameter. When both `Keep` and `Count` are specified, AMPS will not compress any files if the number of files meeting the criteria is less than the number specified in the `Keep` parameter.
`Count` | Specifies the maximum number of files that meet the `Age` and `Pattern` criteria to compress. AMPS will compress files matching the criteria, starting with the oldest files, and stop when the number of files specified in this parameter have been compressed. There is no default for this parameter. When both `Keep` and `Count` are specified, AMPS will not compress any files if the number of files meeting the criteria is less than the number specified in the `Keep` parameter.

This module does not add any variables to the AMPS context.

#### Removing Files

AMPS provides the following module for removing files. Use this action to remove error log files that are no longer needed. AMPS loads this module by default.

Caution

This action cannot be used to safely remove journal files (also known as transaction log fies). Use the actions described in Manage Journal Files for these files.

Removing Files
Module Name | Does
--- | ---
`amps-action-do-remove-files` | Removes files that match the specified pattern that are older than the specified age. This action accepts an arbitrary pattern, and removes files that match that pattern. While AMPS attempts to protect against deleting journal files, using a pattern that removes files that are critical for AMPS, for the application, or for the operating system may result in loss of data. The module does not recurse into directories. It skips open files. The module does not remove AMPS journals (that is, files that end with a `.journal` extension), and reports an error if a file with that extension matches the specified `Pattern`. The commands to remove files are executed with the current permissions of the AMPS process.

This module requires an `Age` parameter that specifies the age of the files to remove, as determined by the update to the file. This module also requires a `Pattern` parameter that specifies a pattern for locating files to remove.

Parameters for Removing Files
Parameter | Description
--- | ---
Age | Specifies the age of files to process. The module removes any file older than the specified `Age` that matches the specified `Pattern`. For example, when the `Age` is `5d`, only files that have not been modified within 5 days and that match the pattern will be processed by the module. There is no default for this parameter.
Pattern | Specifies the pattern for files to remove. The module removes any files that match the specified `Pattern` that have not been modified more recently than the specified `Age`. This parameter is interpreted as a Unix shell globbing pattern. It is not interpreted as a regular expression. As with other parameters that use the file system, when the pattern specified is a relative path, the parameter is interpreted relative to the current working directory of the AMPS process. When the pattern specified is an absolute path, AMPS uses the absolute path. There is no default for this parameter.
`Keep` | Specifies the number of files that meet the `Age` and `Pattern` criteria to retain. When this parameter is specified, AMPS will remove files matching the criteria, starting with the oldest files, and stop when the number of remaining files is the number specified in this parameter. There is no default for this parameter. When both `Keep` and `Count` are specified, AMPS will not remove any files if the number of files meeting the criteria is less than the number specified in the `Keep` parameter.
`Count` | Specifies the maximum number of files that meet the `Age` and `Pattern` criteria to remove. AMPS will remove files matching the criteria, starting with the oldest files, and stop when the number of files specified in this parameter have been removed. There is no default for this parameter. When both `Keep` and `Count` are specified, AMPS will not remove any files if the number of files meeting the criteria is less than the number specified in the `Keep` parameter.

This module does not add any variables to the AMPS context.

#### Deleting Messages from SOW

AMPS also provides modules for deleting SOW contents. The `amps-action-do-delete-sow` module deletes messages from the specified SOW topic.

This module requires the `Topic`, `MessageType` and `Filter` parameters in order to delete the desired message.

Parameters for Deleting SOW Messages
Parameter | Description
--- | ---
Topic | The name of the SOW topic from which to delete messages. This parameter supports regular expressions. There is no default for this parameter.
MessageType | The message type of the SOW topic or topics to delete from. There is no default for this parameter.
Filter | Set the filter to apply. Only messages matching that filter will be deleted.

This module does not add any variables to the AMPS context.

#### Compacting a SOW File

AMPS also provides a module for reducing the unused space in a SOW file. The `amps-action-do-compact-sow` module rearranges the messages in the SOW into a smaller amount of space, where possible. Since AMPS uses memory-mapped files to store messages for the SOW topic, this can also potentially reduce the memory footprint of the topic.

This module can compact a specific SOW file or the SOW files for every topic in the instance.

While messages are being added or updated within a topic in the SOW, AMPS reuses free space when possible. It is not necessary to compact the SOW file during most normal operations. This action is most useful after an activity peak that leaves a large amount of unneeded space in the file, or in installations where space is at a premium. Depending on the file size, the number of topics to be compacted, and the amount of free space, the reorganization that this operation performs may require a noticeable amount of I/O bandwidth.

60East recommends that this action run during a maintenance window or in response to a critical lack of disk space. This operation will pause updates to the topic while it is being compacted, reducing overall throughput even if the compaction process runs quickly.

When a `Topic` and `MessageType` are provided, this module compacts the SOW file for that topic. Otherwise, the module compacts the file for all topics in the SOW.

Parameters for Deleting SOW Messages
Parameter | Description
--- | ---
`Topic` | The name of the SOW topic from which to compact. This option must be specified if the `MessageType` is provided. There is no default for this parameter.
`MessageType` | The message type of the SOW topic or topics to compact. This option must be specified if the `Topic` is provided. There is no default for this parameter.

This module does not add any variables to the AMPS context.

#### Querying a SOW Topic

AMPS provides a module for querying a SOW topic. The `amps-action-do-query-sow` queries the SOW topic, and stores the first message returned by the SOW query into a user-defined variable.

This module requires the `Topic`, `MessageType` and `Filter` parameters to identify the query to run. This module requires the `CaptureData` parameter in order to be able to store the result of the query.

Parameters for Querying SOW Messages
Parameter | Description
--- | ---
Topic | The name of the topic to query. This topic must be a SOW topic, a view, a queue, or a conflated topic. There is no default for this parameter. This parameter supports regular expressions.
MessageType | The message type of the topic to query. There is no default for this parameter
Filter | Set the filter to apply. If a `Filter` is present, only messages matching that filter will be returned by the query.
CaptureData | Sets the name of the variable within which AMPS will store the first message returned.
`DefaultData` | If no records are found, AMPS stores the `DefaultData` in the variable specified by `CaptureData`.
`OrderBy` | An `OrderBy` expression to use to order the results returned by the query. For example, to order in descending order of the `/date` field in the messages, you would provide an `OrderBy` option of `/date DESC`.
`Options` | The options for the query. This action accepts any valid option for a `sow` command except the `top_n` option (since this action is already limited to a `top_n` value of `1`).

Once you query messages from the SOW topic, you can use the captured data in other actions. The example below uses `amps-action-do-query-sow` to query the SOW on a schedule in order to echo messages to the log for diagnostic purposes:

    <Actions>
        <Action>
            <On>
                <Module>amps-action-on-schedule</Module>
                <Options>
                    <Every>Saturday at 23:59</Every>
                    <Name>Diagnostic_Schedule</Name>
                </Options>
            </On>
            <Do>
                <Module>amps-action-do-query-sow</Module>
                <Options>
                    <MessageType>xml</MessageType>
                    <Topic>SOW_TOPIC</Topic>
                    <Filter>/Trans/Order/@Oname = 'PURCHASE'</Filter>
                    <CaptureData>AMPS_DATA</CaptureData>
                </Options>
            </Do>
            <Do>
                <Module>amps-action-do-extract-values</Module>
                <Options>
                    <MessageType>xml</MessageType>
                    <Data>{{AMPS_DATA}}</Data>
                    <Value>SAVED_VARIABLE=/Value</Value>
                </Options>
            </Do>
            <Do>
                <Module>amps-action-do-echo-message</Module>
                <Options>
                    <Message>{{SAVED_VARIABLE}} was in the message</Message>
                </Options>
            </Do>
        </Action>
    </Actions>

#### Manage Security

AMPS provides modules for managing the security features of an instance.

Authentication and entitlement can be enabled or disabled, which is useful for debugging or auditing purposes. You can also reset security and authentication, which clears the AMPS internal caches and gives security and authentication modules the opportunity to reinitialize themselves, for example, by re-parsing an entitlements file.

AMPS loads the following modules by default:

Security Modules
Module Name | Does
--- | ---
`amps-action-do-disable-authentication` | Disables authentication for the instance.
`amps-action-do-disable-entitlement` | Disables entitlement for the instance.
`amps-action-do-enable-authentication` | Enables authentication for the instance.
`amps-action-do-enable-entitlement` | Enables entitlement for the instance.
`amps-action-do-reset-authentication` | Resets authentication by clearing AMPS caches and reinitializing authentication.
`amps-action-do-reset-entitlement` | Resets entitlement by clearing AMPS caches and reinitializing entitlement.

These modules require no parameters. The `amps-action-do-reset-authentication` module and the `amps-action-do-reset-entitlement` module accept an optional `Transport` parameter which specifies the transport to reset.

Parameters for Reset Authentication or Entitlement
Parameter | Description
--- | ---
`Transport` | The name of the transport for which to reset authentication or entitlements. If no name is provided, these modules affect all transports.
`AuthenticationId` | The authentication ID of the client for which to reset entitlements. If no ID is provided, these modules affect all clients.

These modules do not add any variables to the AMPS context.

#### Enable and Disable a Transport

AMPS provides modules that can enable and disable specific transports. The `amps-action-do-enable-transport` module enables a transport. The `amps-action-do-disable-transport` module disables a transport.

Transport Action Modules
Module Name | Does
--- | ---
`amps-action-do-enable-transport` | Enables a specific transport.
`amps-action-do-disable-transport` | Disables a specific transport.

Both modules require the name of the transport to disable or enable.

Parameters for Managing Transports
Parameter | Description
--- | ---
`Transport` | The name of the transport to enable or disable. If no name is provided, the module affects all transports.

Both modules do not add any variables to the AMPS context.

#### Publishing Messages

The `amps-action-do-publish-message` module publishes a message into a specified topic.

Publishes from this action are treated as publishes from an AMPS client inside the AMPS engine. This means that:

- There are no user credentials associated with the publish, so entitlements are not applied.
- There is no special handling for the publish. The publish is recorded in the transaction log exactly as if it arrived from outside of the instance and is processed within the instance as if the publish had arrived from an external publisher.

Warning

This action is treated by the AMPS engine as a publish from an internal AMPS client. When an `amps-action-do-publish-message` runs in response to the `amps-action-on-publish-message` event or the `amps-action-on-deliver-message` event, use caution, the message published from this action could cause the event to trigger again.

This warning includes cases where the action publishes to a topic directly monitored by the action and cases where the action monitors a view and publishes to an underlying topic of the view. The warning also applies to configurations in which two or more actions “cross publish” to topics that are monitored by the other action. An example of the last case is an action that monitors `TopicOne` and publishes to `TopicTwo`, while another action monitors `TopicTwo` and publishes to `TopicOne`.

The result of a configuration like the ones described above is called a publish loop. AMPS does not support unterminated publish loops or loops that produce a large number of cycles before terminating.

To publish a message, this module requires a `Topic`, the `MessageType` to publish on and also the `Data` that the message will contain. In addition to that, this module also accepts optional parameters listed below:

Parameters for Publishing Messages
Parameter | Description
--- | ---
Topic | The topic of the message being published.
MessageType | The message type for the topic. There is no default for this parameter.
Data | The data that the message will contain.
`Delta` | Whether to use a delta publish. When this option is present, and the value is `true`, the action will use a delta publish.
`UpdateOnly` | Specifies whether a delta publish is allowed to insert a record, or only update a record. When a delta publish is specified (that is, `Delta` is `true` ), and this option is set to `true`, AMPS will only accept the publish if there is a record present to be updated. When no value is specified, this option is `false`

This module does not add any variables to the AMPS context.

#### Manage Replication

AMPS provides modules for downgrading replication destinations that fall behind and upgrading them again when they catch up.

Replication Management Modules
Module Name | Does
--- | ---
`amps-action-do-downgrade-replication` | Downgrades replication connections from synchronous to asynchronous if the age of the last acknowledged message is older than a specified time period.
`amps-action-do-upgrade-replication` | Upgrades previously-downgraded replication connections from asynchronous to synchronous if the age of the last acknowledged message is more recent than a specified time period. This action has no effect on replication destinations that are specified as `async` in the configuration file.

The modules determine when to downgrade and upgrade based on the age of the oldest message that a destination has not yet acknowledged. When using these modules, it is important that the thresholds for the modules are not set too close together, otherwise; AMPS may repeatedly upgrade and downgrade the connection when the destination is consistently acknowledging messages at a rate close to the threshold values. To avoid this, 60East recommends that the `Age` set for the upgrade module is 1/2 of the age used for the downgrade module.

The `amps-action-do-downgrade-replication` module accepts the following options:

Parameters for Downgrading Replication
Parameter | Description
--- | ---
Age | Specifies the maximum message age at which AMPS downgrades a replication destination to `async`. When this action runs, AMPS downgrades any destination for which the oldest unacknowledged message is older than the specified `Age`. For example, when the `Age` is `5m`, AMPS will downgrade any destination where a message older than 5 minutes has not been acknowledged. There is no default for this parameter.
`GracePeriod` | The approximate time to wait after start up before beginning to check whether to downgrade links. The `GracePeriod` allows time for other AMPS instances to start up and for connections to be established between AMPS instances.

The `amps-action-do-upgrade-replication` module only applies to destinations configured as `sync` that have been previously downgraded. The module accepts the following options:

Parameters for Upgrading Replication
Parameter | Description
--- | ---
Age | Specifies the maximum message age at which a previously-downgraded destination will be upgraded to `sync` mode. When this action runs, AMPS upgrades any destination that has been previously downgraded where the oldest unacknowledged message is more recent than the time value specified in the `Age` parameter. For example, if a destination has been downgraded to `async` mode and the `Age` is `2m`, AMPS will upgrade the destination when the oldest unacknowledged message to that destination is less than 2 minutes old. There is no default for this parameter.
`GracePeriod` | The approximate time to wait after start up before beginning to check whether to upgrade links. The `GracePeriod` allows time for other AMPS instances to start up, and for connections to be established between AMPS instances.

These modules do not add any variables to the AMPS context.

#### Extract Values

The `amps-action-do-extract-values` module extracts message values from a message and stores the values in a variable.

To extract values from a message, this module requires the `MessageType` and `Value` parameters. In addition to that, this module also accepts an optional parameter listed below:

Parameters for Extract Values
Parameter | Description
--- | ---
MessageType | The message type for the message to parse. There is no default for this parameter.
Value | An assignment statement that specifies the variable to store the extracted value in and the XPath identifier for the value to extract. This action can contain any number of `Value` elements, each providing an assignment statement. The format of the assignment is as follows:
    variable=amps-expression
For example, the following assignment statement stores the value of the `/previousRegionCode` within the message to the variable `PREVIOUS_REGION`. After this action runs, the content of the variable can be referenced in subsequent action steps as `{{PREVIOUS_REGION}}`.
    PREVIOUS_REGION=/previousRegionCode
Likewise, the following assignment statement creates a string from the values of the `/firstName` and `/lastName` fields within the message, and stores that to the variable `COMBINED_NAME`. After this action runs, the content of the variable can be referenced in subsequent action steps as `{{COMBINED_NAME}}`.
    COMBINED_NAME=CONCAT(/firstName, ' ', /lastName)
There is no default for this option. If no `Value` options are provided, AMPS does not save any values from the parsed message.
`Data` | Contains the data to parse. Typically it is a message received from a publish event or retrieved from a SOW query. There is no default value for this parameter. If it is omitted, AMPS will not parse data when the action is run.

The module `amps-action-do-extract-values` adds the variables specified by the `Value` options to the current context.

#### Translate Data

The `amps-action-do-translate-data` action allows you to translate the value from variables in the current context. One common use for this action is to translate a large number of status values into a smaller number of states before publishing that information in a message. For example, an order processing system may track a large number of finely-grained status codes, while the reporting view for customers may want to map those status codes to a smaller set of codes such as “pending”, “shipped” and “delivered”. This action allows you to easily translate those codes within AMPS.

When used to assemble a message, this action provides equivalent results to a set of nested conditional statements in a view projection. However, if you are using actions to parse, assemble and publish messages, this action gives you the ability to change values.

Parameters for Translate Data
Parameter | Description
--- | ---
Data | The data to translate. Most often, this is the value of a variable in the current context.
Value | The variable to store the translated value in.
`Case` | A translation statement. The translation statement takes the form of `original_value=translated_value`. This action allows you to provide any number of `Case` statements. The action matches the `Data` provided to the `original_value` in each `Case` statement. When it finds a matching value, the action stores the translated value in the variable identified by the `Value` statement. For example, the following translation statement translates a value of `credit_check_in_progress` to a value of `pending`
    <Case>credit_check_in_progress=pending</Case>
There is no default for this option.
`Default` | The default translation. AMPS sets the value of the variable to the contents of this element if no `Case` statement matches the `Data` provided. This element is optional. If no `Default` is specified, AMPS uses the value of the original `Data` as the default translation.

#### Increment Counter

The `amps-action-do-increment-counter` module allows AMPS to increment a counter by a value. Counters persist across action runs, and are saved in the instance memory until the instance is restarted.

If a counter with the specified name does not currently exist in the instance when the action runs, AMPS creates the counter with a value of 0 and then immediately increments it with the specified value. If the counter is already present, AMPS will simply increment the counter.

To see an example of `amps-action-do-increment-counter`, refer to the Action Configuration Examples section at the end of this chapter.

This module requires a `Key` that tells AMPS which counter to increment and a `Value` that tells AMPS where to store the incremented value.

Parameter for Increment Counter
Parameter | Description
--- | ---
Key | The name of the counter that AMPS will increment. There is no default value for this parameter.
Value | The variable in which to store the current value of the counter.

This module adds a variable that contains the counter, as specified in the `Value` parameter, to the current context.

#### Raising a Custom Event

The AMPS action system provides a way to create custom events and run an action when the custom event is raised. A custom event is raised by the `amps-action-do-execute-event` action. Events are received by the `amps-action-on-execute-event` module.

This action requires one of the following parameters:

Parameters for Do Execute Event
Parameter | Description
--- | ---
Event | The name of the event to raise. There is no default value for this parameter.
EventVariable | The variable from which to retrieve the name of the event to raise. There is no default value for this parameter.

This module does not add any variables to the AMPS context.

#### Executing System Commands

The `amps-action-do-execute-system` module allows AMPS to execute system commands.

The parameter for this module is simply the command. The command executes in the current working directory of the AMPS process, with the credentials and environment of the AMPS process.

The thread used to execute the command is monitored by AMPS thread monitoring. This means that the command must complete within a short period of time (on the order of a second or two at the longest) or AMPS may consider the thread to have become deadlocked.

Parameter for Execute System
Parameter | Description
--- | ---
`Command` | The command to execute. When the action runs, this command is executed as a shell command on the system where AMPS is running.

This module does not add any variables to the AMPS context.

Caution

This module executes system commands with the credentials of the AMPS process. It is possible to damage the system, interrupt the AMPS service, or cause data loss by executing commands with this module. 60East recommends against using any data extracted from an AMPS message in the command executed.

#### Managing Queue Transfer Requests

AMPS provides actions to enable and disable the “proxied transfer” setting for message queues. As described in the Failover and Queue Message Ownership section of the Replicating Messages Between Instances chapter of the AMPS User Guide, this setting allows an instance to manage ownership of a queue message that is owned by an instance that is offline (or otherwise unreachable from this instance). 60East recommends that these actions only be configured in situations where the administrative interface is unavailable. Unlike most other settings for which actions are provided, the “proxied transfer” setting is intended for disaster recovery rather than normal maintenance.

The `amps-action-do-enable-proxied-transfer` action can be used to enable proxied transfer for a queue. The `amps-action-do-disable-proxied-transfer` action can be used to disable proxied transfer for a queue.

Enabling proxied transfer will allow this instance to take ownership of messages owned by an unreachable instance, allowing those messages to be delivered. However, it also introduces the risk of duplicate delivery and duplicate processing in cases where the instance that currently owns the message is still online (but the replication network connection has failed), or in cases where the instance that currently owns the message becomes available again and begins servicing requests. See the Failover and Queue Message Ownership section for more details.

Although an action is provided for flexibility, 60East does not recommend that the `enable_proxied_transfer` setting is enabled automatically, due to the possibility of duplicate delivery. Instead, this action should be configured to run in response to action by an administrator, after the administrator determines that one of the instances that contains the queue is, in fact, offline and that the possibility of duplicate processing is an acceptable risk.

Caution

These actions are intended to assist in maintaining message delivery from a distributed queue during an outage of one of the instances that services the queue. When this setting is enabled, the possibility of duplicate delivery exists.

These actions require the following parameters:

Parameters for Do Enable Proxied Transfer
Parameter | Description
--- | ---
Topic | The name of the queue topic for which to enable or disable proxied transfer. There is no default value for this parameter.
MessageType | The message type of the topic for which to enable or disable proxied transfer. There is no default value for this parameter.

This module does not add any variables to the AMPS context.

#### Debugging Actions

AMPS provides modules for debugging your AMPS action configuration.

Debugging Modules
Module Name | Does
--- | ---
`amps-action-do-nothing` | Takes no action. Does not modify the state of AMPS in any way. The module simply logs that it was called.
`amps-action-do-echo-message` | Echoes the specified message to the log. The message appears in the log as message `29-0103`, at `info` level. The logging configuration must allow this message to be recorded for the output of this action to appear in the log.

The `amps-action-do-nothing` module requires no parameters.

The `amps-action-do-echo-message` module requires the following parameter:

Parameter for Echo Message
Parameter | Description
--- | ---
`Message` | The message to echo. The default for this parameter is simply an empty string.

These modules do not add any variables to the AMPS context.

#### Creating a Minidump

AMPS provides a module for creating minidumps. The `amps-action-do-minidump` module provides a way for developers and/or administrators to easily create minidumps for diagnostic purposes.

Running this module does not cause AMPS to exit.

Module to Create Minidump
Module Name | Does
--- | ---
`amps-action-do-minidump` | Creates a minidump.

This module does not require any parameters.

This module does not add any variables to the AMPS context.

#### Shut Down AMPS

The `amps-action-do-shutdown` module shuts down AMPS. This module is registered as the default action for several Linux signals, as described in Default Signal Actions.

Causing this module to run is the recommended way to shut down AMPS. This is most often done by sending `SIGINT` to the AMPS process, which is handled by `amps-action-on-signal` to run this module.

Shut Down Module
Module Name | Does
--- | ---
`amps-action-do-shutdown` | Shuts down AMPS.

This module does not require any parameters.

This module does not add any variables to the AMPS context.

### If Element: Conditionally Stop Action Sequence

AMPS includes the ability to run actions only if certain conditions are true. For some actions (such as the replication management actions), the condition is included as a part of the action. In other cases, AMPS provides `If` actions.

An `If` action is evaluated each time the execution of an action reaches the `If` action. When the condition specified in an `If` action is `true`, AMPS proceeds to the next `Do` action. If the condition in an `If` action is `False`, AMPS does not run any further `Do` elements in the action.

#### File System Usage

AMPS provides the following `If` module for taking action based on the file system capacity. AMPS loads this module by default:

File System Usage
Module Name | Does
--- | ---
`amps-action-if-file-system-usage` | Checks whether the specified path on the filesystem meets the specified usage level. If so, allows execution to continue. If not, stops the action.

Parameters for Running Actions Based on File System Usage
Parameter | Description
--- | ---
Path | Specifies the filesystem path to monitor. The AMPS process must have sufficient permissions to check the disk usage for this path at the time the check runs. There is no default for this parameter.
GreaterThan | The threshold to check, specified as a percentage. If the provided path has more space used than specified in this parameter, subsequent `Do` and `If` blocks will run. Otherwise, the action will complete with this step.

This module does not add any variables to the AMPS context.

For example, the following action will log a message in the AMPS log every minute when the file system becomes more than 90% full, and perform a full shutdown of AMPS if the file system is more than 98% full.

    <Actions>
        <Action>
            <On>
                <Module>amps-action-on-schedule</Module>
                <Options>
                    <Every>1m</Every>
                </Options>
            </On>
            <If>
                <Module>amps-action-if-file-system-usage</Module>
                <Options>
                    <GreaterThan>90%</GreaterThan>
                    <Path>/mnt/fastdrive/amps</Path>
                </Options>
            </If>
            <Do>
                <Module>amps-action-do-echo-message</Module>
                <Options>
                    <Message>ALERT: You're getting low on space!</Message>
                </Options>
            </Do>
            <If>
                <Module>amps-action-if-file-system-usage</Module>
                <Options>
                    <GreaterThan>98%</GreaterThan>
                    <Path>/mnt/fastdrive/amps</Path>
                </Options>
            </If>
            <Do>
                <Module>amps-action-do-echo-message</Module>
                <Options>
                    <Message>CRITICAL: Shutting down AMPS</Message>
                </Options>
            </Do>
            <Do>
                <Module>amps-action-do-shutdown</Module>
            </Do>
        </Action>
    </Actions>

#### Conditional Expression

AMPS provides the following `If` module for taking action based on the results of an AMPS expression:

Running an action if a condition is true
Module Name | Does
--- | ---
`amps-action-if-condition` | Evaluates the specified condition. If the condition is true, allows execution to continue. Otherwise, stops the action.

Parameters for Running Actions Based on a Conditional Expression
Parameter | Description
--- | ---
Condition | Specifies the condition to evaluate. Context variables are expanded before the condition is evaluated. The condition may use AMPS functions. The condition must be a valid AMPS filter when evaluated. If variable expansion produces an expression that is not a valid filter, the module logs an error and stops the action. Notice that the condition does not have direct access to an AMPS message (even if this `If` step is a part of an action started by a message, such as the `amps-action-on-publish-message` `On` event). When the `On` step for this action provides an option for conditional execution (for example, the `Filter` option for `amps-action-on-publish-message`), it is more efficient to use that `Filter` to only run the action if the filter matches, than to use this step to stop the action. You can use the `amps-action-do-extract-values` `Do` step to extract values into context variables, or use a filter on the `On` event to only run the action for messages that meet the criteria. There is no default for this parameter.

This module does not add any variables to the AMPS context.

For example, the following action will enable the transport named `subscriber-transport` when a client named `ImportantPublisher` logs on, and disable the transport named `subscriber-transport` when the client named `ImportantPublisher` disconnects. An action of this type could be used to ensure that subscribers can only connect to an instance of AMPS if the `ImportantPublisher` is also connected to that instance. (Not shown in this snippet is that the `subscriber-transport` is set to the initial state of `disabled`, and that there is a different transport available for `ImportantPublisher` to connect to.)

    <Actions>
        <Action>
            <On>
                <Module>amps-action-on-logon-client</Module>
            </On>
            <If>
                <Module>amps-action-if-condition</Module>
                <Options>
                    <Condition>"{{AMPS_CLIENT_NAME}}" = "ImportantPublisher"</Condition>
                </Options>
            </If>
            <Do>
                <Module>amps-action-do-enable-transport</Module>
                <Options>
                    <Transport>subscriber-transport</Transport>
                </Options>
            </Do>
          </Action>
          <Action>
            <On>
                <Module>amps-action-on-disconnect-client</Module>
            </On>
            <If>
                <Module>amps-action-if-condition</Module>
                <Options>
                    <Condition>"{{AMPS_CLIENT_NAME}}" = "ImportantPublisher"</Condition>
                </Options>
            </If>
            <Do>
                <Module>amps-action-do-disable-transport</Module>
                <Options>
                    <Transport>subscriber-transport</Transport>
                </Options>
            </Do>
          </Action>
     </Actions>

### Action Configuration Examples

#### Archive Transaction Log Journal Files Older Than One Week, Every Saturday

The listing below asks AMPS to archive transaction log journal files older than 1 week, every Saturday at 12:30 AM.

This configuration moves journal files from the JournalDirectory to the JournalArchiveDirectory, while maintaining the files as an active part of the transaction log (ensuring that they are still available for bookmark replay, replication, and so on):

    <Actions>
        <Action>
            <On>
                <Module>amps-action-on-schedule</Module>
                <Options>
                    <Every>Saturday at 00:30</Every>
                    <Name>Saturday Night Fever</Name>
                </Options>
            </On>
            <Do>
                <Module>amps-action-do-archive-journal</Module>
                <Options>
                    <Age>7d</Age>
                </Options>
            </Do>
        </Action>
    </Actions>

#### Disable and Re-enable Security on Signal

The listing below disables authentication and entitlement when AMPS receives the `USR1` signal. When AMPS receives the `USR2` signal, AMPS re-enables authentication and entitlement. This configuration is, in effect, the configuration that AMPS installs by default for these signals:

    <Actions>
        <Action>
            <On>
                <Module>amps-action-on-signal</Module>
                <Options>
                    <Signal>SIGUSR1</Signal>
                </Options>
            </On>
            <Do>
                <Module>amps-action-do-disable-authentication</Module>
            </Do>
            <Do>
                <Module>amps-action-do-disable-entitlement</Module>
            </Do>
        </Action>
        <Action>
            <On>
                <Module>amps-action-on-signal</Module>
                <Options>
                    <Signal>SIGUSR2</Signal>
                </Options>
            </On>
            <Do>
                <Module>amps-action-do-enable-authentication</Module>
            </Do>
            <Do>
                <Module>amps-action-do-enable-entitlement</Module>
            </Do>
        </Action>
    </Actions>

#### Reset Entitlements for a Disconnected Client

The listing below resets entitlement cache for a user when a client with that authentication ID is disconnected. This is a practical approach when an application expects that each user will have a single connection to AMPS.

    <Actions>
        <Action>
            <On>
                <Module>amps-action-on-disconnect-client</Module>
            </On>
            <Do>
                <Module>amps-action-do-reset-entitlement</Module>
                <Options>
                    <AuthenticationId>{{AMPS_AUTHENTICATION_ID}}</AuthenticationId>
                </Options>
            </Do>
        </Action>
    </Actions>

#### Extract Values on Publish of a Message

The listing below extracts values from a locally published xml message and stores them into VALUE.

    <Actions>
        <Action>
            <On>
                <Module>amps-action-on-publish-message</Module>
                <Options>
                    <Topic>message-sow</Topic>
                    <MessageType>xml</MessageType>
                    <MessageSource>local</MessageSource>
                </Options>
            </On>
            <Do>
                <Module>amps-action-do-extract-values</Module>
                <Options>
                    <MessageType>xml</MessageType>
                    <Data>{{AMPS_DATA}}</Data>
                    <Value>VALUE = /VALUE</Value>
                </Options>
            </Do>
        </Action>
    </Actions>

#### Increment a Counter and Echo a Message on Signal

The listing below increments a counter and echoes the counter’s value when AMPS receives the `USR1` signal.

    <Actions>
        <Action>
            <On>
                <Module>amps-action-on-signal</Module>
                <Options>
                    <Signal>SIGUSR1</Signal>
                </Options>
            </On>
            <Do>
                <Module>amps-action-do-increment-counter</Module>
                <Options>
                    <Key>MY_COUNTER</Key>
                    <Value>CURRENT_COUNTER_VALUE</Value>
                </Options>
            </Do>
            <Do>
                <Module>amps-action-do-echo-message</Module>
                <Options>
                    <Message>AMPS has gotten {{CURRENT_COUNTER_VALUE}}
                        SIGUSR1 signals.</Message>
                </Options>
            </Do>
        </Action>
    </Actions>

#### Recording Expired Queue Messages in a Dead Letter Topic

The listing below detects when a message expires from a queue, and publishes those messages to a dead letter topic.

    <Actions>
        <Action>
            <On>
                <Module>amps-action-on-sow-expire-message</Module>
                <Options>
                    <Topic>interesting-queue</Topic>
                    <MessageType>json</MessageType>
                </Options>
            </On>
            <On>
                <Module>amps-action-on-sow-expire-message</Module>
                <Options>
                    <Topic>another-interesting-queue</Topic>
                    <MessageType>json</MessageType>
                </Options>
            </On>
            <Do>
                <Module>amps-action-do-publish-message</Module>
                <Options>
                    <Topic>dead-letter</Topic>
                    <MessageType>json</MessageType>
                    <Data>{"topic":"{{AMPS_TOPIC}}","message":{{AMPS_DATA}} }</Data>
                </Options>
            </Do>
        </Action>
    </Actions>

#### Copy a Message to a Different Topic When a Timeout is Exceeded

The listing below, in effect, copies messages from the `Orders` topic to the `Orders_Stale` topic when the status has been `PENDING` for more than 5 seconds.

    <Actions>
        <Action>
            <On>
                <Module>amps-action-on-message-condition-timeout</Module>
                <Options>
                    <MessageType>nvfix</MessageType>
                    <Topic>Orders</Topic>
                    <Filter>/status = 'PENDING'</Filter>
                    <Duration>5s</Duration>
                </Options>
            </On>
            <Do>
                <Module>amps-action-do-publish-message</Module>
                <Options>
                    <MessageType>nvfix</MessageType>
                    <Topic>Orders_Stale</Topic>
                    <Data>{{AMPS_DATA}}</Data>
                </Options>
            </Do>
        </Action>
    </Actions>

#### Shutting Down AMPS When Filesystem Fills

The listing below directs AMPS to perform a graceful shutdown when the filesystem becomes full, with a check run every 3 seconds.

    <Actions>
        <Action>
            <On>
                <Module>amps-action-on-schedule</Module>
                <Options>
                    <Every>3s</Every>
                </Options>
            </On>
            <If>
             <Module>amps-action-if-file-system-usage</Module>
                <Options>
                    <Path>./</Path>
                    <GreaterThan>99%</GreaterThan>
                </Options>
            </If>
            <Do>
                <Module>amps-action-do-shutdown</Module>
           </Do>
        </Action>
    </Actions>

#### Archive Transaction Log Journal Files Older Than a Specified Age in Response to Admin Request

The listing below directs AMPS to archive journals when a query is made to the `/amps/administrator/actions/archive_journals` resource. The request must include an `AGE` query parameter. When the request is submitted, AMPS will mark journals older than the specified age for archival.

    <Actions>
        <Action>
            <On>
                <Module>amps-action-on-admin</Module>
                <Options>
                    <Path>archive_journals</Path>
                    <RequiredParameter>AGE</RequiredParameter>
                    <Name>Archive Journals</Name>
                </Options>
            </On>
            <Do>
                <Module>amps-action-do-archive-journal</Module>
                <Options>
                    <Age>{{AGE}}</Age>
                </Options>
            </Do>
        </Action>
    </Actions>

The `On` configuration for this action specifies that the action will run when a request is made to the `/amps/administrator/actions/archive_journals` resource, and that the request must contain an `AGE` query parameter. When the request runs, the `AGE` parameter is added to the context for the action.

The `Do` configuration for this action runs the `amps-action-do-archive-journal` module, and fills in the value of the `AGE` parameter provided by the HTTP request.

If the `AGE` parameter is missing, the `amps-action-on-admin` module will refuse the request.

If the `AGE` parameter is not a valid interval (for example, if someone provided the string `"LastThursday"` instead of a valid AMPS interval like `48h`), the `amps-action-do-archive-journal` module will log an error and refuse to run the request.