Using the GitHub CLI on a runner

Example overview

This article uses an example workflow to demonstrate some of the main CI features of GitHub Actions. When this workflow is triggered, it automatically runs a script that checks whether the GitHub Docs site has any broken links. If any broken links are found, the workflow uses the GitHub CLI to create a GitHub issue with the details.

The following diagram shows a high level view of the workflow's steps and how they run within the job:

Overview diagram of workflow steps

Features used in this example

The example workflow demonstrates the following capabilities of GitHub Actions:

Feature	Implementation
Running a workflow at regular intervals:	`schedule`
Setting permissions for the token:	`permissions`
Preventing a job from running unless specific conditions are met:	`if`
Referencing secrets in a workflow:	Secrets
Cloning your repository to the runner:	`actions/checkout`
Installing `node` on the runner:	`actions/setup-node`
Using a third-party action:	`peter-evans/create-issue-from-file`
Running shell commands on the runner:	`run`
Running a script on the runner:	Using `script/check-english-links.js`
Generating an output file:	Piping the output using the `>` operator
Checking for existing issues using GitHub CLI:	`gh issue list`
Commenting on an issue using GitHub CLI:	`gh issue comment`

Example workflow

The following workflow was created by the GitHub Docs Engineering team. To review the latest version of this file in the github/docs repository, see check-all-english-links.yml.

Note: Each line of this workflow is explained in the next section at "Understanding the example."

YAML

name: Check all English links

# **What it does**: This script once a day checks all English links and reports in issues.
# **Why we have it**: We want to know if any links break.
# **Who does it impact**: Docs content.

on:
  workflow_dispatch:
  schedule:
    - cron: '40 19 * * *' # once a day at 19:40 UTC / 11:40 PST

permissions:
  contents: read
  issues: write

jobs:
  check_all_english_links:
    name: Check all links
    if: github.repository == 'github/docs-internal'
    runs-on: ubuntu-latest
    env:
      GITHUB_TOKEN: ${{ secrets.DOCUBOT_READORG_REPO_WORKFLOW_SCOPES }}
      FIRST_RESPONDER_PROJECT: Docs content first responder
      REPORT_AUTHOR: docubot
      REPORT_LABEL: broken link report
      REPORT_REPOSITORY: github/docs-content
    steps:
      - name: Check out repo's default branch
        uses: actions/checkout@v3
      - name: Setup Node
        uses: actions/setup-node@v3
        with:
          node-version: 16.13.x
          cache: npm
      - name: npm ci
        run: npm ci
      - name: npm run build
        run: npm run build
      - name: Run script
        run: |
          script/check-english-links.js > broken_links.md

      # check-english-links.js returns 0 if no links are broken, and 1 if any links
      # are broken. When an Actions step's exit code is 1, the action run's job status
      # is failure and the run ends. The following steps create an issue for the
      # broken link report only if any links are broken, so `if: ${{ failure() }}`
      # ensures the steps run despite the previous step's failure of the job.

      - if: ${{ failure() }}
        name: Get title for issue
        id: check
        run: echo "::set-output name=title::$(head -1 broken_links.md)"
      - if: ${{ failure() }}
        name: Create issue from file
        id: broken-link-report
        uses: peter-evans/create-issue-from-file@b4f9ee0a9d4abbfc6986601d9b1a4f8f8e74c77e
        with:
          token: ${{ env.GITHUB_TOKEN }}

          title: ${{ steps.check.outputs.title }}
          content-filepath: ./broken_links.md
          repository: ${{ env.REPORT_REPOSITORY }}
          labels: ${{ env.REPORT_LABEL }}
      - if: ${{ failure() }}
        name: Close and/or comment on old issues
        env:
          NEW_REPORT_URL: 'https://github.com/${{ env.REPORT_REPOSITORY }}/issues/${{ steps.broken-link-report.outputs.issue-number }}'
        run: |
          gh alias set list-reports "issue list \
                                       --repo ${{ env.REPORT_REPOSITORY }} \
                                       --author ${{ env.REPORT_AUTHOR }} \
                                       --label '${{ env.REPORT_LABEL }}'"

          # Link to the previous report from the new report that triggered this
          # workflow run.

          previous_report_url=$(gh list-reports \
                                  --state all \
                                  --limit 2 \
                                  --json url \
                                  --jq '.[].url' \
                                  | grep -v ${{ env.NEW_REPORT_URL }} | head -1)

          gh issue comment ${{ env.NEW_REPORT_URL }} --body "⬅️ [Previous report]($previous_report_url)"

          # If an old report is open and assigned to someone, link to the newer
          # report without closing the old report.

          for issue_url in $(gh list-reports \
                                  --json assignees,url \
                                  --jq '.[] | select (.assignees != []) | .url'); do
            if [ "$issue_url" != "${{ env.NEW_REPORT_URL }}" ]; then
              gh issue comment $issue_url --body "➡️ [Newer report](${{ env.NEW_REPORT_URL }})"
            fi
          done

          # Link to the newer report from any older report that is still open,
          # then close the older report and remove it from the first responder's
          # project board.

          for issue_url in $(gh list-reports \
                                  --search 'no:assignee' \
                                  --json url \
                                  --jq '.[].url'); do
            if [ "$issue_url" != "${{ env.NEW_REPORT_URL }}" ]; then
              gh issue comment $issue_url --body "➡️ [Newer report](${{ env.NEW_REPORT_URL }})"
              gh issue close $issue_url
              gh issue edit $issue_url --remove-project "${{ env.FIRST_RESPONDER_PROJECT }}"
            fi
          done

Understanding the example

The following table explains how each of these features are used when creating a GitHub Actions workflow.

Code	Explanation
YAML `name: Check all English links`	The name of the workflow as it will appear in the "Actions" tab of the GitHub repository.
YAML `on: workflow_dispatch: schedule: - cron: '40 20 * * *' # once a day at 20:40 UTC / 12:40 PST`	Defines the `workflow_dispatch` and `scheduled` as triggers for the workflow: The `workflow_dispatch` lets you manually run this workflow from the UI. For more information, see `workflow_dispatch`. The `schedule` event lets you use `cron` syntax to define a regular interval for automatically triggering the workflow. For more information, see `schedule`.
YAML `permissions: contents: read issues: write`	Modifies the default permissions granted to `GITHUB_TOKEN`. This will vary depending on the needs of your workflow. For more information, see "Assigning permissions to jobs."
YAML `jobs:`	Groups together all the jobs that run in the workflow file.
YAML `check_all_english_links: name: Check all links`	Defines a job with the ID `check_all_english_links`, and the name `Check all links`, that is stored within the `jobs` key.
YAML `if: github.repository == 'github/docs-internal'`	Only run the `check_all_english_links` job if the repository is named `docs-internal` and is within the `github` organization. Otherwise, the job is marked as skipped.
YAML `runs-on: ubuntu-latest`	Configures the job to run on an Ubuntu Linux runner. This means that the job will execute on a fresh virtual machine hosted by GitHub. For syntax examples using other runners, see "Workflow syntax for GitHub Actions."
YAML `env: GITHUB_TOKEN: ${{ secrets.DOCUBOT_READORG_REPO_WORKFLOW_SCOPES }} REPORT_AUTHOR: docubot REPORT_LABEL: broken link report REPORT_REPOSITORY: github/docs-content`	Creates custom environment variables, and redefines the built-in `GITHUB_TOKEN` variable to use a custom secret. These variables will be referenced later in the workflow.
YAML `steps:`	Groups together all the steps that will run as part of the `check_all_english_links` job. Each job in the workflow has its own `steps` section.
YAML `- name: Check out repo's default branch uses: actions/checkout@v3`	The `uses` keyword tells the job to retrieve the action named `actions/checkout`. This is an action that checks out your repository and downloads it to the runner, allowing you to run actions against your code (such as testing tools). You must use the checkout action any time your workflow will run against the repository's code or you are using an action defined in the repository.
YAML `- name: Setup Node uses: actions/setup-node@v3 with: node-version: 16.8.x cache: npm`	This step uses the `actions/setup-node` action to install the specified version of the `node` software package on the runner, which gives you access to the `npm` command.
YAML `- name: Run the "npm ci" command run: npm ci - name: Run the "npm run build" command run: npm run build`	The `run` keyword tells the job to execute a command on the runner. In this case, the `npm ci` and `npm run build` commands are run as separate steps to install and build the Node.js application in the repository.
YAML `- name: Run script run: \| script/check-english-links.js > broken_links.md`	This `run` command executes a script that is stored in the repository at `script/check-english-links.js`, and pipes the output to a file called `broken_links.md`.
YAML `- if: ${{ failure() }} name: Get title for issue id: check run: echo "::set-output name=title::$(head -1 broken_links.md)"`	If the `check-english-links.js` script detects broken links and returns a non-zero (failure) exit status, then use a workflow command to set an output that has the value of the first line of the `broken_links.md` file (this is used the next step).
YAML `- if: ${{ failure() }} name: Create issue from file id: broken-link-report uses: peter-evans/create-issue-from-file@b4f9ee0a9d4abbfc6986601d9b1a4f8f8e74c77e with: token: ${{ env.GITHUB_TOKEN }} title: ${{ steps.check.outputs.title }} content-filepath: ./broken_links.md repository: ${{ env.REPORT_REPOSITORY }} labels: ${{ env.REPORT_LABEL }}`	Uses the `peter-evans/create-issue-from-file` action to create a new GitHub issue. This example is pinned to a specific version of the action, using the `b4f9ee0a9d4abbfc6986601d9b1a4f8f8e74c77e` SHA.
YAML - if: ${{ failure() }} name: Close and/or comment on old issues env: NEW_REPORT_URL: 'https://github.com/${{ env.REPORT_REPOSITORY }}/issues/${{ steps.broken-link-report.outputs.issue-number }}' run: \| gh alias set list-reports "issue list \ --repo ${{ env.REPORT_REPOSITORY }} \ --author ${{ env.REPORT_AUTHOR }} \ --label '${{ env.REPORT_LABEL }}'" previous_report_url=$(gh list-reports \ --state all \ --limit 2 \ --json url \ --jq '.[].url' \ \| grep -v ${{ env.NEW_REPORT_URL }} \| head -1) gh issue comment ${{ env.NEW_REPORT_URL }} --body "⬅️ [Previous report]($previous_report_url)"	Uses `gh issue list` to locate the previously created issue from earlier runs. This is aliased to `gh list-reports` for simpler processing in later steps. To get the issue URL, the `jq` expression processes the resulting JSON output. `gh issue comment` is then used to add a comment to the new issue that links to the previous one.
YAML `for issue_url in $(gh list-reports \ --json assignees,url \ --jq '.[] \| select (.assignees != []) \| .url'); do if [ "$issue_url" != "$" ]; then gh issue comment $issue_url --body "➡️ [Newer report]($)" fi done`	If an issue from a previous run is open and assigned to someone, then use `gh issue comment` to add a comment with a link to the new issue.
YAML `for issue_url in $(gh list-reports \ --search 'no:assignee' \ --json url \ --jq '.[].url'); do if [ "$issue_url" != "${{ env.NEW_REPORT_URL }}" ]; then gh issue comment $issue_url --body "➡️ [Newer report](${{ env.NEW_REPORT_URL }})" gh issue close $issue_url gh issue edit $issue_url --remove-project "${{ env.FIRST_RESPONDER_PROJECT }}" fi done`	If an issue from a previous run is open and is not assigned to anyone, then: Use `gh issue comment` to add a comment with a link to the new issue. Use `gh issue close` to close the old issue. Use `gh issue edit` to edit the old issue to remove it from a specific GitHub project board.

Next steps

To learn about GitHub Actions concepts, see "Understanding GitHub Actions."
For more step-by-step guide for creating a basic workflow, see "Quickstart for GitHub Actions."
If you're comfortable with the basics of GitHub Actions, you can learn about workflows and their features at "About workflows."