Create Dockerfile

[AnishaM7]

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[github-learning-lab]

Nice work, you committed a Dockerfile. You'll notice at the end of the Dockerfile, we refer to an entrypoint script.

ENTRYPOINT ["/entrypoint.sh"]

The entrypoint.sh script will be run in Docker, and it will define what the action is really going to be doing.

Step 2: Add an entrypoint script

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

⌨️ Activity: Add an entrypoint script and commit it to your branch

1. As a part of this branch and pull request, create a file in the /action-a/ directory titled entrypoint.sh. You can do so with this quicklink

2. Add the following content to the entrypoint.sh file:

   #!/bin/sh -l
   
   sh -c "echo Hello world my name is $INPUT_MY_NAME"

3. Stage and commit the changes

4. Push the changes to GitHub

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I'll respond when I detect a new commit on this branch.

[github-learning-lab]

Nice work adding the entrypoint.sh script.

In entrypoint.sh, all we're doing is outputting a "Hello world" message using an environment variable called MY_NAME.

Next, we'll define the action.yml file which contains the metadata for our action.

action.yml

All actions require a metadata file that uses YAML syntax. The data in the metadata file defines the inputs, outputs and main entrypoint for your action.

Step 3: Add an action metadata file

We will use an input parameter to read in the value of MY_NAME.

⌨️ Activity: Create action.yml

1. As a part of this branch and pull request, create a file titled action-a/action.yml. You can do so using this quicklink or manually.

2. Add the following content to the action.yml file:

   name: "Hello Actions"
   description: "Greet someone"
   author: "[email protected]"
   
   inputs:
     MY_NAME:
       description: "Who to greet"
       required: true
       default: "World"
   
   runs:
     using: "docker"
     image: "Dockerfile"
   
   branding:
     icon: "mic"
     color: "purple"

3. Stage and commit the changes

4. Push the changes to GitHub

---

I'll respond when I detect a new commit on this branch.

[github-learning-lab]

Next, we'll define a workflow that uses the GitHub Action.

Workflow Files

Workflows are defined in special files in the .github/workflows directory, named main.yml.

Workflows can execute based on your chosen event. For this lab, we'll be using the push event.

We'll break down each line of the workflow in the next step.

Step 4: Start your workflow file

First, we'll add the structure of the workflow.

⌨️ Activity: Name and trigger your workflow

1. Create a file titled .github/workflows/main.yml. You can do so using this quicklink or manually:
   • As a part of this branch and pull request, create a workflows directory nested inside the .github directory.
   • In the new .github/workflows/ directory, create a file titled main.yml
2. Add the following content to the main.yml file:

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

3. Stage and commit the changes
4. Push the changes to GitHub

Trouble pushing? Click here.

The main.yml file cannot be edited using an integration. Try editing the file using the web interface, or your command line.

It is possible that you are using an integration (like GitHub Desktop or any other tool that authenticates as you and pushes on your behalf) if you receive a message like the one below:

To https://github.com/your-username/your-repo.git
 ! [remote rejected] your-branch -> your-branch (refusing to allow an integration to update main.yml)
error: failed to push some refs to 'https://github.com/your-username/your-repo.git'

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I'll respond when I detect a new commit on this branch.

[github-learning-lab]

Nice work! 🎉 You added a workflow!

Here's what it means:

• name: A workflow for my Hello World file gives your workflow a 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.
• on: push indicates that your workflow will execute anytime code is pushed to your repository, using the push event.

Next, we need to specify a job or jobs to run.

Actions

Workflows piece together jobs, and jobs piece together steps. We'll now create a job that runs an action. Actions can be used from within the same repository, from any other public repository, or from a published Docker container image. We'll use an action that we'll define in this repository.

We'll add the block now, and break it down in the next step.

Step 5: Run an action from your workflow file

Let's add the expected action to the workflow.

⌨️ Activity: Add an action block to your workflow file

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

   jobs:
     build:
       name: Hello world action
       runs-on: ubuntu-latest
       steps:
         - uses: actions/checkout@v1
         - uses: ./action-a
           with:
             MY_NAME: "Mona"

2. Click Start commit in the top right of the workflow editor
3. Type your commit message and commit your changes directly to your branch

Trouble pushing?

The main.yml file cannot be edited using an integration. Try editing the file using the web interface, or your command line.

It is possible that you are using an integration (like GitHub Desktop or any other tool that authenticates as you and pushes on your behalf) if you receive a message like the one below:

To https://github.com/your-username/your-repo.git
 ! [remote rejected] your-branch -> your-branch (refusing to allow an integration to update main.yml)
error: failed to push some refs to 'https://github.com/your-username/your-repo.git'

---

I'll respond when I detect a new commit on this branch.

[github-learning-lab]

Nice, you just added an action block to your workflow file! Here are some important details about why each part of the block exists and what each part does.

• jobs: is the base component of a workflow run
• build: is the identifier we're attaching to this job
• name: is the name of the job, this is displayed on GitHub when the workflow is running
• runs-on: 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: the linear sequence of operations that make up a job
• uses: actions/checkout@v1 uses a community action called checkout to allow the workflow to access the contents of the repository
• uses: ./action-a provides the relative path to the action we created in the action-a directory of the repository
• with: is used to specify the input variables that will be available to your action in the runtime environment. In this case, the input variable is MY_NAME, and it is currently initialized to "Mona".

Your action has been triggered!

Your repository now contains an action (defined in the /action-a/ folder) and a workflow (defined in the ./github/workflows/main.yml file).

This action will run any time a new commit is created or pushed to the remote repository. Since you just created a commit, the workflow should have been triggered. This might take a few minutes since it's the first time running in this repository.

Seeing your Action in action

The status of your action is shown here in the pull request (look for All checks have passed below), or you can click the "Actions" tab in your repository. From there you will see the actions that have run, and you can click on the action's "Log" link to view details.

Step 6: Trigger the workflow

⌨️ Activity: See your action trigger the workflow

You've done the work, now sit back and see your action trigger the workflow!

---

I will respond when I detect your action has run and reported a status.

Actions can take a minute or two to run. Sometimes, I also respond too fast for the page to update! If you don't see a response from your action, wait a few seconds and refresh the page.

[github-learning-lab]

Almost there, but the workflow didn't run.

Here's some possible reasons why:

• files aren't in proper directories
• your script isn't executable

Troubleshooting steps

Check out the action's output in the Actions tab.

You can also use the following to help you troubleshoot:

For /action-a/entrypoint.sh

Problem	Solution
entrypoint.sh isn't executable.	In your shell, run chmod +x action-a/entrypoint.sh on this branch and push it up to GitHub.
The file isn't called entrypoint.sh (case sensitive).	Rename the file using the UI or your CLI.
The directory action-a doesn't exist.	Create the action-a folder and move entrypoint.sh to action-a.
The entrypoint.sh file isn't inside the action-a folder.	Move entrypoint.sh to action-a.

For /action-a/Dockerfile

Problem	Solution
The file isn't called Dockerfile (case sensitive).	Rename the file using the UI or your CLI.
The directory action-a doesn't exist.	Create the action-a folder and move the Dockerfile to action-a.
The Dockerfile isn't inside the action-a folder.	Move the Dockerfile to action-a.

For .github/workflows/main.yml

Problem	Solution
There's some problem with your syntax in main.yml.	Copy and paste the code exactly as is shown in this PR (check for extra spaces, symbols) or see if an error appears in the action logs.
The file isn't called main.yml (case sensitive).	Rename the file using the UI or your CLI.
The directory .github/workflows doesn't exist.	Create the .github/workflows folders and move main.yml to .github/workflows.
The main.yml file isn't inside the .github/workflows folder.	Move main.yml to .github/workflows.

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Next time you commit, your action will try to run. I'll respond when that occurs.