PYSPARK-DEPS.md

PySpark dependencies

Using PySpark on a cluster requires all cluster nodes to have those Python packages installed that are required by the PySpark job. Such a deployment can be cumbersome, especially when running in an interactive notebook.

The spark-extension package allows installing Python packages programmatically by the PySpark application itself (PySpark ≥ 3.1.0). These packages are only accessible by that PySpark application, and they are removed on calling spark.stop().

Either install the spark-extension Maven package, or the pyspark-extension PyPi package (on the driver only), as described here.

Installing packages with pip

Python packages can be installed with pip as follows:

# noinspection PyUnresolvedReferences
from gresearch.spark import *

spark.install_pip_package("pandas", "pyarrow")

Above example installs PIP packages pandas and pyarrow via pip. Method install_pip_package takes any pip command line argument:

# install packages with version specs
spark.install_pip_package("pandas==1.4.3", "pyarrow~=8.0.0")

# install packages from package sources (e.g. git clone https://github.com/pandas-dev/pandas.git)
spark.install_pip_package("./pandas/")

# install packages from git repo
spark.install_pip_package("git+https://github.com/pandas-dev/pandas.git@main")

# use a pip cache directory to cache downloaded and built whl files
spark.install_pip_package("pandas", "pyarrow", "--cache-dir", "/home/user/.cache/pip")

# use an alternative index url (other than https://pypi.org/simple)
spark.install_pip_package("pandas", "pyarrow", "--index-url", "https://artifacts.company.com/pypi/simple")

# install pip packages quietly (only disables output of PIP)
spark.install_pip_package("pandas", "pyarrow", "--quiet")

Installing Python projects with Poetry

Python projects can be installed from sources, including their dependencies, using Poetry:

# noinspection PyUnresolvedReferences
from gresearch.spark import *

spark.install_poetry_project("../my-poetry-project/", poetry_python="../venv-poetry/bin/python")

Example

This example uses install_pip_package in a Spark standalone cluster.

First checkout the example code:

git clone https://github.com/G-Research/spark-extension.git
cd spark-extension/examples/python-deps

Build a Docker image based on the official Spark release:

docker build -t spark-extension-example-docker .

Start the example Spark standalone cluster consisting of a Spark master and one worker:

docker compose -f docker-compose.yml up -d

Run the example.py Spark application on the example cluster:

docker exec spark-master spark-submit --master spark://master:7077 --packages uk.co.gresearch.spark:spark-extension_2.12:2.12.0-3.5 /example/example.py

The --packages uk.co.gresearch.spark:spark-extension_2.12:2.12.0-3.5 argument tells spark-submit to add the spark-extension Maven package to the Spark job.

Alternatively, install the pyspark-extension PyPi package via pip install and remove the --packages argument from spark-submit:

docker exec spark-master pip install --user pyspark_extension==2.11.1.3.5
docker exec spark-master spark-submit --master spark://master:7077 /example/example.py

This output proves that PySpark could call into the function func, wich only works when Pandas and PyArrow are installed:

+---+
| id|
+---+
|  0|
|  1|
|  2|
+---+

Test that spark.install_pip_package("pandas", "pyarrow") is really required by this example by removing this line from example.py …

 from pyspark.sql import SparkSession

 def main():
     spark = SparkSession.builder.appName("spark_app").getOrCreate()

     def func(df):
         return df

     from gresearch.spark import install_pip_package

-    spark.install_pip_package("pandas", "pyarrow")
     spark.range(0, 3, 1, 5).mapInPandas(func, "id long").show()

 if __name__ == "__main__":
     main()

… and running the spark-submit command again. The example does not work anymore, because the Pandas and PyArrow packages are missing from the driver:

Traceback (most recent call last):
  File "/opt/spark/python/lib/pyspark.zip/pyspark/sql/pandas/utils.py", line 27, in require_minimum_pandas_version
ModuleNotFoundError: No module named 'pandas'

Finally, shutdown the example cluster:

docker compose -f docker-compose.yml down