Run a Python script on Github

Github provides a way for running scripts that exist in your repository, called Github Actions. It enables you create to create a workflow to build, package, publish, deploy, test and do other stuff with your project. Travis CI offers similiar functionality, but is not for free anymore, while Github still is.

Running Python is posible on Github. There are workflows for testing or publishing a Python package. You can also just run a Python script that generates something like a file and save that file in the repository, automatically.

1 Create a job

For running a job that will be picked up by the Github workflow, you’ll have to set up the following folder structure in the root of your repository.

• Create a folder with the name .github.
• Inside that folder, create a folder with the name workflows.
• Create a yaml file inside workflows with a name like run-python.yml.

  <repo>/.github/workflows/run-python.yml

The YAML file is where you put the workflow syntax that instructs Github what to do.

2 Building the actual job

First, you should provide a name.

name: run-python

Second, you create a trigger for the job defined by on. A common trigger is a push to Github.

on:
  push:
    branches:
      - main

Triggering the job on a schedule based on a cron pattern is also useful.

on:
  schedule:
    - cron: '0 0 * * *'

Then you configure the actual job you want to run. This example will start a build on the lastest version of Ubuntu.

It will checkout your code (actions/checkout@v2), install Python (actions/setup-python@v2), install the relevant Python packages and run your actual Python script. The actions, like actions/checkout@v2 are handy scripts that you can find in the Github marketplace.

Lastly it will commit and push (ad-m/[email protected]) the resulting changes to the main branch.

jobs:
  build:
    runs-on: ubuntu-latest
    steps:

      - name: checkout repo content
        uses: actions/checkout@v2

      - name: setup python
        uses: actions/setup-python@v2
        with:
          python-version: '3.8.2'
          
      - name: install python packages
        run: |
          python -m pip install --upgrade pip
          pip install requests
          
      - name: execute py script
        run: python3 <the-name-of-your-python-script>
          
      - name: commit files
        run: |
          git config --local user.email "[email protected]"
          git config --local user.name "GitHub Action"
          git add -A
          git commit -m "update data" -a
          
      - name: push changes
        uses: ad-m/[email protected]
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          branch: main

Keep in mind that the yaml will not work when the indentation is not correct. The nesting style of a yaml is comparable to Python. The full run-python.yml should look something like this:

name: run-python

on:
  schedule:
    - cron: '0 0 * * *'

jobs:
  build:
    runs-on: ubuntu-latest
    steps:

      - name: checkout repo content
        uses: actions/checkout@v2

      - name: setup python
        uses: actions/setup-python@v2
        with:
          python-version: '3.8.2'
          
      - name: install python packages
        run: |
          python -m pip install --upgrade pip
          pip install requests
          
      - name: execute py script
        run: python3 <the-name-of-your-python-script>
          
      - name: commit files
        run: |
          git config --local user.email "[email protected]"
          git config --local user.name "GitHub Action"
          git add -A
          git commit -m "update data" -a
          
      - name: push changes
        uses: ad-m/[email protected]
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          branch: main  

3 See it run

Check out the newly created job under the Actions tab on the homepage of your repository. If you are using the on push trigger in the YAML, you’ll see that it starts to run right after you pushed the new workflow job to Github.