GitHub Actions

Types of Actions

Actions come in two types:

(Docker) container actions

They allow the environment to be packaged with the GitHub Actions code and can only execute in the GitHub-Hosted Linux environment.
JavaScript actions

Workflow Files

Workflows are defined in special files in the .github/workflows directory, named main.yml. Workflows can execute based on your chosen event. Inside a workflow file, several declarations take place.

Name
```
name: workflow_name
```
This name appears on any pull request or in the Actions tab. The name is especially useful when there are multiple workflows in your repository.
Event
```
on: event
```
It indicates that your workflow will execute anytime the specified event is triggered. For example,
```
on: push
```
Actions

Workflows piece together jobs, and jobs piece together steps. Actions can be used from within the same repository, from any other public repository, or from a published Docker container image.

An action block can contain:
- Jobs
```
jobs:
```
  It is the base component of a workflow run.
- Build
```
build:
```
  It’s the identifier we’re attaching to this job.
- Name
```
name: action_name
```
  It’s the name of the job, this is displayed on GitHub when the workflow is running.
- Runs On
```
runs-on: ubuntu-latest
```
  Defines the type of machine to run the job on. The machine can be either a GitHub-hosted runner or a self-hosted runner.
- Steps
```
steps:
```
  A linear sequence of operations that make up a job.
- Uses
```
uses: actions/checkout@v1
```
  Uses a community action called checkout to allow the workflow to access the contents of the repository.
```
uses: ./dir
```
  Provides the relative path to the action in the dir directory of the repository.
- Input variables
```
with:
  VARIABLE_1: "value"
  VARIABLE_2: "val"
```
  It’s used to specify the input variables that will be available to your action in the runtime environment.

Following the GitHub Actions: Hello World course

I will take note of the procedure of the course to be able to look back at it for any reference I might need.

Step 1: Add a Dockerfile

Create a file titled action-a/Dockerfile
- Create a new branch. Branches should be named intentionally, so a good name for this branch could be first-action
- On the new branch, create a directory: action-a
- In the action-a directory, create a file titled Dockerfile
Inside the Dockerfile, paste

This component was made by Stratis Dermanoutsos. The code can be found here.
Commit your file
Open a pull request with your new branch against main

Step 2: Add an entrypoint script

An entrypoint script must exist in our repository so that Docker has something to execute.

As a part of this branch and pull request, create a file in the action-a directory titled entrypoint.sh
Inside the entrypoint.sh, paste

This component was made by Stratis Dermanoutsos. The code can be found here.

In this file, all we’re doing is outputting a “Hello world” message using an environment variable called MY_NAME.
Stage and commit the changes
Push the changes to GitHub

Step 3: Add an action metadata file

As a part of this branch and pull request, create a file titled action-a/action.yml
Inside it, paste

This component was made by Stratis Dermanoutsos. The code can be found here.
Stage and commit the changes
Push the changes to GitHub

Step 4: Start your workflow file

Create a file titled .github/workflows/main.yml

Inside the file, paste

name: A workflow for my Hello World file
on: push

Stage and commit the changes
Push the changes to GitHub

Step 5: Run an action from your workflow file

As a part of this branch and pull request, edit .github/workflows/main.yml to append the following content:

This component was made by Stratis Dermanoutsos. The code can be found here.
Stage and commit the changes
Push the changes to GitHub

Step 6: Trigger the workflow

Go to the repository on GitHub

Navigate to

Actions -> 'Added action to run' -> 'Hello world action' -> 'Run /./action-a'

At the bottom of the stdout, you should see the string “Hello world my name is Mona”

Step 7: Incorporate the workflow

Merge this pull request
Delete your branch