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GitHub Actions usage for frontend engineers

Workflow Functionality

With GitHub Actions, we can create workflows, which are pipelines or automated processes that can be triggered by a variety of events.

Workflows are made up of jobs, which are sets of steps or commands, representing tasks such as building and testing.

The workflows you may find relevant are the "Continuous Integration" and "Pull Request" workflows.

Continuous Integration workflow

This workflow runs whenever changes are pushed to a branch. No matter how many commits you make locally, the workflow only gets triggered on push.

It's responsible for typical CI processes, consisting of jobs such as building, testing, and deploying.

It also has a job that lints files across the entire repo. For PRs, this gets skipped in favor of the linting job in the "Pull Request" workflow, which only lints files changed.

Pull Request workflow

This workflow runs whenever a pull request is created or commits are pushed to a pull request.

Its jobs run certain checks on changed files, including:

  • Linting only files changed, which differs from the "Continuous Integration" linting that runs on all files in the repo

  • Raising concerns when Sentry calls are made in case PII is mistakenly included in the report

  • Reminding that icons should have ARIA attributes when they are interactive

  • Double checking whether disabling ESLint rules is completely necessary

When issues are detected, these checks annotate or comment on the relevant sections of code.

Daily Production Deploy workflow

This workflow runs at a specific time daily and is less relevant to the standard development process. More detailed information on this workflow can be found in the Deployments documentation.

Workflow Statuses

Viewing all workflow statuses for a commit

Pull requests

Pull requests display status checks at the bottom of the page. Click on "Details" of any job to view its console output.

List of job statuses shows green check marks to the left of the job name. On the right, a details link can be clicked to view the console output.

Alternatively, directly navigate to the "Checks" tab. To view a particular job's output, expand the workflow that contains it by clicking the chevron.

To view workflow statuses for previous commits in the PR, select a commit from the commit hash dropdown.

Screenshot shows a view of a PR with Checks tab selected. Select the desired commit via the commit dropdown menu. On the left a list of jobs appears for that commit. Each job can be expanded to view workflow summary, pipeline, and console output by selecting the name of the job in the list.

Commit statuses

Commit histories show icons to indicate the overall status of a commit.

Click on the icon and then click on "Details" of any job to view its console output.

Screenshot shows commit history, listing commits by date including the name, author, time, and green check mark to show success of the commit. Selecting the green check mark shows a list of the checks that passed for that commit, with an option to click Details for any item on the list.

Viewing the summary and pipeline visual for a workflow run

Screenshot shows pipeline details for a specific commit. On the left is a list of jobs with status icons. On the right, the same jobs with the same status icons are shown in a flow chart sequence.

Every workflow run has a summary page where you can see a graph of the pipeline to track its progress.

Each box or node in the graph represents a job or matrix of jobs with an icon to indicate status (pass, fail, skipped, in progress).

To get to this page, navigate to the view with the job console outputs and click on the workflow name or annotation icon.

Matrix jobs

A matrix represents a set of jobs that all run the same steps with some variations depending on certain variables.

Click on any matrix in the graph to expand and view the jobs in it. The job names indicate the variations in parentheses.

Build for each environment

Screenshot shows an expanded matrix using the example Matrix Build. This has been expanded to show 3 jobs within the Matrix including Build (vagovdev) Build (vagovstaging) and Build (vagovprod) with the associated times to completion.

Cypress tests split into smaller batches

Screenshot shows an expanded matrix using the example Matrix Cypress E2E Tests. This has been expanded to show at least 5 jobs within the Matrix including Cypress E2E Tests (0) Cypress E2E Tests (1) Cypress E2E Tests (2) and so on, with the associated times to completion.

Job dependencies

Lines between jobs indicate dependencies. The order of execution is left-to-right; jobs on the right of the line depend on and run after jobs on the left.

Hover over a job to highlight the jobs that it directly depends on and the jobs that directly depend on it.

The lines can sometimes overlap, making the dependency graph unclear. The relationships can be made more apparent by hovering over the relevant jobs to highlight them or clicking matrix jobs to expand them.

Screenshot shows that in the flow chart view of the pipeline for a certain commit, lines between the matrices indicate dependencies. Matrix Build shows that it is a dependency for Nightwatch E2E tests which is a dependency for Matrix Archive.

Cancelling and re-running failed workflows

In either the workflow statuses view for a commit or the summary page of a workflow run, you may cancel or re-run a workflow.

To cancel a workflow, click the button to "Cancel workflow".

Cancel workflow button is shown to the right of the status icon and name of the commit.

To re-run a workflow that has failed, expand the dropdown to "Re-run jobs" and click the button to "Re-run all jobs".

Re-run jobs button is a dropdown menu on the right side of a page, next to Artifacts. The dropdown is selected to show the option Re-run all jobs.

Using the GitHub CLI to interact with workflow runs

You may use the gh command line tool to interact with workflow runs.



gh run list

List recent workflow runs

gh run view

View details for a workflow run or one of its jobs

gh run watch

Watch a workflow run while it executes

gh run rerun

Rerun a failed workflow run

gh run download

Download artifacts generated by runs

With gh run list, you get a list of the most recent workflow runs and their IDs, which can be passed as an argument to the other commands.

If you don't pass specific IDs, the commands will allow you to pick among a limited list of recent runs. In the case of gh run download, you can choose to download artifacts from the most recent run that had artifacts.

Run gh run view --web to see the workflow run summary in the GitHub UI.

Secrets Injection

If any sensitive information is to be used in a workflow, it should be stored in the AWS Param Store to avoid any secrets being exposed unintentionally. They can be injected using the action marvinpinto/action-inject-ssm-secrets.

Note: Secrets should be minified to avoid unintended behavior. Secrets are processed line by line and those lines are obscured by the GHA workflow in an attempt to keep your information safe. So, for example, non-minified JSON would result in { and } being obscured with ***, as the curly braces are on their own lines so they would be an “exact match” for sensitive characters.


In general, you may view the console logs for details about any job execution.

Some jobs provide additional information that may be useful for troubleshooting.


The linting job in the "Pull Request" workflow annotates any problematic areas in the changed code.

Screenshot shows an expanded linting warning that says Check warning on line 22 in the given file path.

Unit tests

Unit tests produce a "Unit Tests Summary" in the list of jobs under the workflow.

It contains the following information:

  • Number of tests run, skipped, and failed

  • Annotations for any test failures

  • Code coverage report

Screenshot shows list of jobs in the workflow on the left including one called Unit Tests Summary, which is expanded on the right. The expanded summary shows 7051 tests run, 0 skipped, 1 failed. The annotation shows details on the failed unit test.

Cypress E2E tests

Cypress tests produce a "Cypress Tests Summary", which is similar to the unit tests summary.

  • It contains the number of tests run, skipped, and failed as well as annotations for test failures.

  • Additionally, there is an external link to a Mochawesome test report, which is more comprehensive.

Screenshot shows the Cypress Tests Summary that mirrors the Unit Test Summary shown above. The Cypress Test Summary shows 315 tests run, 0 skipped, 0 failed, and includes a link called Mochawesome Report

There are also screenshot and video artifacts generated for any test failures.

The screenshot highlights the location of test artifacts, which are located in an Artifacts dropdown to the right of the commit name. After clicking Artifacts 11, a menu appears with individual artifacts that are available to download.

Edge Cases

Multiple runs of the same workflow

Commits can sometimes show multiple, seemingly duplicate, runs of a workflow (e.g., "Continuous Integration").

Screenshot shows the list of jobs run in a workflow (viewed by selecting the Checks tab) an shows that Continuous Integration ran multiple times for the same commit.

This can happen when a branch is created from that commit and pushed without adding any new commits. As a result, the workflow is triggered by a push event for the same commit hash.

Navigating to the summary of the run should indicate which branch triggered the run.

Screenshot shows the Summary view, which shows a list of pushed commits, the status, and the total duration of those. The example shown is author pushed a commit name from branch name. The commit name and branch name are highlighted.

Test summaries appear under wrong workflows

Occasionally, the Unit Tests Summary and Cypress Tests Summary may appear under workflows other than "Continuous Integration".

This is a bug with how GitHub Actions and check runs that hasn't yet been fixed.

Although they may appear under different workflows, they can still be found in the overall list of PR check statuses or in commit statuses.

Screenshot shows expanded CodeQL matrix showing that the Unit Test Summary and Cypress Test Summary appeared in the incorrect workflow. The summaries have status checks.

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