GitHub Actions Tutorial — Contexts

Contexts

Contexts are objects that provide information about the workflow run, the repository, the runner, and more. You access them inside expressions to make decisions and pass data.

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Available Contexts

Context	Description
github	Event, repository, actor, ref, sha
env	Environment variables
vars	Configuration variables
secrets	Encrypted secrets
steps	Step outputs and outcomes
needs	Job outputs and results
job	Current job info
runner	Runner OS, arch, temp directory
matrix	Current matrix values
strategy	Matrix strategy config
inputs	Workflow dispatch inputs

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github Context

The most commonly used context — provides details about the event and repository:

steps:
  - run: |
      echo "Event: ${{ github.event_name }}"
      echo "Ref: ${{ github.ref }}"
      echo "Branch: ${{ github.ref_name }}"
      echo "SHA: ${{ github.sha }}"
      echo "Actor: ${{ github.actor }}"
      echo "Repository: ${{ github.repository }}"
      echo "Run ID: ${{ github.run_id }}"
      echo "Run number: ${{ github.run_number }}"
      echo "Workflow: ${{ github.workflow }}"

Frequently Used github Properties

Property	Example Value	When
${{ github.event_name }}	push, pull_request	Always
${{ github.ref }}	refs/heads/main	Always
${{ github.ref_name }}	main, v1.0.0	Always
${{ github.sha }}	abc123...	Always
${{ github.actor }}	octocat	Always
${{ github.event.pull_request.number }}	42	pull_request events
${{ github.event.pull_request.head.ref }}	feature/my-branch	pull_request events
${{ github.event.release.tag_name }}	v2.1.0	release events

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steps Context

Access outputs and outcomes from previous steps in the same job:

steps:
  - name: Generate version
    id: ver
    run: echo "version=2.1.0" >> "$GITHUB_OUTPUT"

  - name: Check tests
    id: test
    continue-on-error: true
    run: npm test

  - name: Use step data
    run: |
      echo "Version: ${{ steps.ver.outputs.version }}"
      echo "Test outcome: ${{ steps.test.outcome }}"
      echo "Test conclusion: ${{ steps.test.conclusion }}"

Property	Description
${{ steps.<id>.outputs.<key> }}	Step output value
${{ steps.<id>.outcome }}	success, failure, cancelled, skipped
${{ steps.<id>.conclusion }}	Same, but respects continue-on-error

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needs Context

Access outputs and results from upstream jobs:

jobs:
  build:
    runs-on: ubuntu-latest
    outputs:
      version: ${{ steps.ver.outputs.version }}
    steps:
      - id: ver
        run: echo "version=2.1.0" >> "$GITHUB_OUTPUT"

  deploy:
    needs: build
    runs-on: ubuntu-latest
    steps:
      - run: |
          echo "Version: ${{ needs.build.outputs.version }}"
          echo "Build result: ${{ needs.build.result }}"

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matrix Context

Access the current matrix combination in matrix jobs:

strategy:
  matrix:
    os: [ubuntu-latest, windows-latest]
    node: [18, 20]

steps:
  - run: echo "OS: ${{ matrix.os }}, Node: ${{ matrix.node }}"

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runner Context

Information about the runner executing the job:

steps:
  - run: |
      echo "OS: ${{ runner.os }}"            # Linux, Windows, macOS
      echo "Arch: ${{ runner.arch }}"        # X64, ARM64
      echo "Name: ${{ runner.name }}"
      echo "Temp: ${{ runner.temp }}"
      echo "Tool cache: ${{ runner.tool_cache }}"

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inputs Context

For workflow_dispatch and reusable workflow inputs:

on:
  workflow_dispatch:
    inputs:
      environment:
        type: choice
        options: [staging, production]

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - run: echo "Deploying to ${{ inputs.environment }}"

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Common Mistakes

Mistake	Fix
Accessing step output from another job	Use needs context with job outputs, not steps
Context not available	Some contexts are only available in certain scopes (e.g., matrix only in matrix jobs)
Typo in context property	Properties are case-sensitive; check docs for exact names
Missing github.event subproperty	The event payload varies by trigger type; check webhook docs

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Quick Reference

Context	Scope	Common Use
github	Everywhere	Branch, SHA, actor, event data
env	Everywhere	Environment variables
steps	Same job	Step outputs, outcomes
needs	Dependent jobs	Job outputs, results
matrix	Matrix jobs	Current matrix values
runner	Steps	OS, arch, temp directory
secrets	Steps, job env	Encrypted secrets
inputs	Dispatch/reusable	Workflow inputs

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