# Python

## Overview

Python scripts can be automated in Zuar Runner via [command line jobs](/help/mitto/job-types/command-line/).

.. image:: assets/python-1.png
   :alt: Command Line Job

## Upload a Python Script to Zuar Runner

Any Python scripts to be run by Zuar Runner must exist on Zuar Runner's file
system. Use Zuar Runner's :ref:`files` to upload the

Python script.

## Create a Python Virtual Environment

*This step only needs to be performed once.*

If your Python scripts require any packages outside of [Python's
standard library](https://docs.python.org/3/library/), you should
create a Python virtual environment and install your packages into
that environment.

We use [Python's venv
module](https://docs.python.org/3/library/venv.html) for creating
separate Python virtual environments.

Create a [command line job](/jobs/command-line/) that runs this command:

```bash
/app/env/bin/python3 -m venv /var/mitto/data/{virtualenv_directory}
```

Replace `{virtualenv_directory}` with a directory name for your virtual environment.

Run this job **once** to create a directory and initialize a new
Python virtual environment in the directory. This directory will be
referenced when you want to use this Python virtual environment.

## Install Python Packages in the Python Virtual Environment with Pip

*This step only needs to be performed once.*

Create a [command line job](/help/mitto/command-line/) that runs this command:

```bash
/var/mitto/data/{virtualenv_directory}/bin/pip3 install {python_package}
```

Replace `{virtualenv_directory}` with the directory name of your
virtual environment and replace `{python_package}` with the name of
your Python package.

Run this job **once** to install a Python package in your Python
virtual environment using [pip](https://pip.pypa.io/en/stable/).

Note you can install multiple Python packages at once like this:

```bash
/var/mitto/data/{virtualenv_directory}/bin/pip3 install {python_package1} {python_package2} {python_package3}
```

## Create a Command Line Job to Run a Python Script

Create a [command line job](/jobs/command-line/) that runs this command:

```bash
/var/mitto/data/{virtualenv_directory}/bin/python3 /var/mitto/data/{python_script}.py
```

Every time this job is run, it will execute the Python script using the Python virtual environment.

## Example Python Script

The following script (`test_python_script.py`) will create a CSV: `written_by_python.csv`.

```bash
#!/usr/bin/env python3
"""NOTE: You must use python3"""
with open("/var/mitto/data/written_by_python.csv", "w") as f:
    f.write("id,name\n")
    f.write("1,Allen\n")
    f.write("2,Steve\n")
```

One thing to note is that `python` won't work, as Zuar Runner has `python3` installed.

Running the job should create a file that looks like this:

.. image:: assets/python__image-1.png