Metadata-Version: 2.1
Name: pysparkler
Version: 0.4.dev1681497870
Summary: A tool that upgrades your PySpark scripts to the latest Spark version as per Spark migration Guideline
Home-page: https://github.com/holdenk/spark-upgrade
License: Apache-2.0
Author: Dhruv Pratap
Author-email: dhruv.pratap@gmail.com
Maintainer: Holden Karau
Maintainer-email: holden@pigscanfly.ca
Requires-Python: >=3.10,<4.0
Classifier: License :: OSI Approved :: Apache Software License
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.10
Classifier: Programming Language :: Python :: 3.11
Requires-Dist: click (>=8.1.3,<9.0.0)
Requires-Dist: libcst (>=0.4.9,<0.5.0)
Requires-Dist: nbformat (>=5.8.0,<6.0.0)
Requires-Dist: rich (>=13.3.3,<14.0.0)
Project-URL: Repository, https://github.com/holdenk/spark-upgrade
Description-Content-Type: text/markdown

# PySparkler

## About

PySparkler is a tool that upgrades your PySpark scripts to latest Spark version. It is a command line tool that takes a
PySpark script as input and outputs a latest Spark version compatible script. It is written in Python and uses the
[LibCST](https://github.com/Instagram/LibCST) module to parse the input script and generate the output script.

## Basic Usage

Install from PyPI:

```bash
pip install pysparkler
```

Provide the path to the script you want to upgrade:

```bash
pysparkler upgrade --input-file /path/to/script.py
```

## PySpark Upgrades Supported

This tool follows the [Apache Spark Migration guide for PySpark](https://spark.apache.org/docs/latest/api/python/migration_guide/pyspark_upgrade.html)
to upgrade your PySpark scripts. In the latest stable version it supports the following upgrades from the migration guide:

| Migration                                       | Supported | Details                                                                                                                                      |
|-------------------------------------------------|-----------|----------------------------------------------------------------------------------------------------------------------------------------------|
| Upgrading from PySpark 3.3 to 3.4               | ❌         | [Link](https://spark.apache.org/docs/latest/api/python/migration_guide/pyspark_upgrade.html#upgrading-from-pyspark-3-3-to-3-4)               |
| Upgrading from PySpark 3.2 to 3.3               | ✅         | [Link](https://spark.apache.org/docs/latest/api/python/migration_guide/pyspark_upgrade.html#upgrading-from-pyspark-3-2-to-3-3)               |
| Upgrading from PySpark 3.1 to 3.2               | ✅         | [Link](https://spark.apache.org/docs/latest/api/python/migration_guide/pyspark_upgrade.html#upgrading-from-pyspark-3-1-to-3-2)               |
| Upgrading from PySpark 2.4 to 3.0               | ✅         | [Link](https://spark.apache.org/docs/latest/api/python/migration_guide/pyspark_upgrade.html#upgrading-from-pyspark-2-4-to-3-0)               |
| Upgrading from PySpark 2.3 to 2.4               | ✅         | [Link](https://spark.apache.org/docs/latest/api/python/migration_guide/pyspark_upgrade.html#upgrading-from-pyspark-2-3-to-2-4)               |
| Upgrading from PySpark 2.3.0 to 2.3.1 and above | ✅         | [Link](https://spark.apache.org/docs/latest/api/python/migration_guide/pyspark_upgrade.html#upgrading-from-pyspark-2-3-0-to-2-3-1-and-above) |
| Upgrading from PySpark 2.2 to 2.3               | ❌         | [Link](https://spark.apache.org/docs/latest/api/python/migration_guide/pyspark_upgrade.html#upgrading-from-pyspark-2-2-to-2-3)               |
| Upgrading from PySpark 1.4 to 1.5               | ❌         | [Link](https://spark.apache.org/docs/latest/api/python/migration_guide/pyspark_upgrade.html#upgrading-from-pyspark-1-4-to-1-5)               |
| Upgrading from PySpark 1.0-1.2 to 1.3           | ❌         | [Link](https://spark.apache.org/docs/latest/api/python/migration_guide/pyspark_upgrade.html#upgrading-from-pyspark-1-0-1-2-to-1-3)           |

## Features Supported

The tool supports the following features:

| Feature                          | Supported |
|----------------------------------|-----------|
| Upgrade PySpark Python script    | ✅         |
| Upgrade PySpark Jupyter Notebook | ✅         |
| Dry-run Mode                     | ✅         |
| Verbose Mode                     | ✅         |

### Upgrade PySpark Python script

The tool can upgrade a PySpark Python script. It takes the path to the script as input and upgrades it in place:

```bash
pysparkler upgrade --input-file /path/to/script.py
```

If you want to output the upgraded script to a different directory, you can use the `--output-file` flag:

```bash
pysparkler upgrade --input-file /path/to/script.py --output-file /path/to/output.py
```

### Upgrade PySpark Jupyter Notebook

The tool can upgrade a PySpark Jupyter Notebook to latest Spark version. It takes the path to the notebook as input and
upgrades it in place:

```bash
pysparkler upgrade --input-file /path/to/notebook.ipynb
```

Similar to upgrading python scripts, if you want to output the upgraded notebook to a different directory, you can use
the `--output-file` flag:

```bash
pysparkler upgrade --input-file /path/to/notebook.ipynb --output-file /path/to/output.ipynb
```

To change the output kernel name in the output Jupyter notebook, you can use the `--output-kernel` flag:

```bash
pysparkler upgrade --input-file /path/to/notebook.ipynb --output-kernel spark33-python3
```

### Dry-Run Mode

For both the above upgrade options, to run in dry mode, you can use the `--dry-run` flag. This will not write the
upgraded script but will print a unified diff of the input and output scripts for you to inspect the changes:

```bash
pysparkler upgrade --input-file /path/to/script.py --dry-run
```

### Verbose Mode

For both the above upgrade options, to run in verbose mode, you can use the `--verbose` flag. This will print tool's
input variables, the input file content, the output content, and a unified diff of the input and output content:

```bash
pysparkler --verbose upgrade --input-file /path/to/script.py
```

## Contributing

For the development, Poetry is used for packing and dependency management. You can install this using:

```bash
pip install poetry
```

If you have an older version of pip and virtualenv you need to update these:

```bash
pip install --upgrade virtualenv pip
```

### Installation

To get started, you can run `make install`, which installs Poetry and all the dependencies of the PySparkler library.
This also installs the development dependencies.

```bash
make install
```

If you don't want to install the development dependencies, you need to install using `poetry install --only main`.

If you want to install the library on the host, you can simply run `pip3 install -e .`. If you wish to use a virtual
environment, you can run `poetry shell`. Poetry will open up a virtual environment with all the dependencies set.

### IDE Setup

To set up IDEA with Poetry:

- Open up the Python project in IntelliJ
- Make sure that you're on latest master (that includes Poetry)
- Go to File -> Project Structure (⌘;)
- Go to Platform Settings -> SDKs
- Click the + sign -> Add Python SDK
- Select Poetry Environment from the left hand side bar and hit OK
- It can take some time to download all the dependencies based on your internet
- Go to Project Settings -> Project
- Select the Poetry SDK from the SDK dropdown, and click OK

For IDEA ≤2021 you need to install the
[Poetry integration as a plugin](https://plugins.jetbrains.com/plugin/14307-poetry/).

Now you're set using Poetry, and all the tests will run in Poetry, and you'll have syntax highlighting in the
pyproject.toml to indicate stale dependencies.

### Linting

`pre-commit` is used for autoformatting and linting:

```bash
make lint
```

Pre-commit will automatically fix the violations such as import orders, formatting etc. Pylint errors you need to fix
yourself.

In contrast to the name suggest, it doesn't run the checks on the commit. If this is something that you like, you can
set this up by running `pre-commit install`.

You can bump the integrations to the latest version using `pre-commit autoupdate`. This will check if there is a newer
version of `{black,mypy,isort,...}` and update the yaml.

### Testing

For Python, `pytest` is used a testing framework in combination with `coverage` to enforce 90%+ code coverage.

```bash
make test
```

To pass additional arguments to pytest, you can use `PYTEST_ARGS`. For example, to run pytest in verbose mode:

```bash
make test PYTEST_ARGS="-v"
```

## Architecture

### Why LibCST?

LibCST is a Python library that provides a concrete syntax tree (CST) for Python code. CST preserves even the
whitespaces of the source code which is very important since we only want to modify the code and not the formatting.

### How does it work?

Using the codemod module of LibCST can simplify the process of writing a PySpark migration script, as it allows us to
write small, reusable transformers and chain them together to perform a sequence of transformations.

### Why Transformer Codemod? Why not Visitor?

The main advantage of using a Transformer is that it allows for more fine-grained control over the transformation
process. Transformer classes can be defined to apply specific transformations to specific parts of the codebase, and
multiple Transformer classes can be combined to form a chain of transformations. This can be useful when dealing with
complex codebases where different parts of the code require different transformations.

More on this can be found [here](https://libcst.readthedocs.io/en/latest/tutorial.html#Build-Visitor-or-Transformer).

