Defining environment variables for a single workflow

To set a custom environment variable for a single workflow, you can define it using theenv key in the workflow file. The scope of a custom variable set by this method is limited to the element in which it is defined. You can define variables that are scoped for:

• The entire workflow, by usingenv at the top level of the workflow file.
• The contents of a job within a workflow, by usingjobs.<job_id>.env.
• A specific step within a job, by usingjobs.<job_id>.steps[*].env.

name: Greeting on variable dayon:  workflow_dispatchenv:  DAY_OF_WEEK: Mondayjobs:  greeting_job:    runs-on: ubuntu-latest    env:      Greeting: Hello    steps:      - name: "Say Hello Mona it's Monday"        run: echo "$Greeting $First_Name. Today is $DAY_OF_WEEK!"        env:          First_Name: Mona

name:Greetingonvariabledayon:workflow_dispatchenv:DAY_OF_WEEK:Mondayjobs:greeting_job:runs-on:ubuntu-latestenv:Greeting:Hellosteps:-name:"Say Hello Mona it's Monday"run:echo"$Greeting $First_Name. Today is $DAY_OF_WEEK!"env:First_Name:Mona

You can accessenv variable values using runner environment variables or using contexts. The example above shows three custom variables being used as runner environment variables in anecho command:$DAY_OF_WEEK,$Greeting, and$First_Name. The values for these variables are set, and scoped, at the workflow, job, and step level respectively. The interpolation of these variables happens on the runner.

The commands in therun steps of a workflow, or a referenced action, are processed by the shell you are using on the runner. The instructions in the other parts of a workflow are processed by GitHub Actions and are not sent to the runner. You can use either runner environment variables or contexts inrun steps, but in the parts of a workflow that are not sent to the runner you must use contexts to access variable values. For more information, seeUsing contexts to access variable values.

Because runner environment variable interpolation is done after a workflow job is sent to a runner machine, you must use the appropriate syntax for the shell that's used on the runner. In this example, the workflow specifiesubuntu-latest. By default, Linux runners use the bash shell, so you must use the syntax$NAME. By default, Windows runners use PowerShell, so you would use the syntax$env:NAME. For more information about shells, seeWorkflow syntax for GitHub Actions.

Defining configuration variables for multiple workflows

You can create configuration variables for use across multiple workflows, and can define them at either theorganization,repository, orenvironment level.

For example, you can use configuration variables to set default values for parameters passed to build tools at an organization level, but then allow repository owners to override these parameters on a case-by-case basis.

When you define configuration variables, they are automatically available in thevars context. For more information, seeUsing thevars context to access configuration variable values.

Creating configuration variables for a repository

To create secrets or variables on GitHub for a personal account repository, you must be the repository owner. To create secrets or variables on GitHub for an organization repository, you must haveadmin access. Lastly, to create secrets or variables for a personal account repository or an organization repository through the REST API, you must have collaborator access.

1. On GitHub, navigate to the main page of the repository.

2. Under your repository name, click Settings. If you cannot see the "Settings" tab, select the dropdown menu, then clickSettings.

   

3. In the "Security" section of the sidebar, select Secrets and variables, then clickActions.

4. Click theVariables tab.

   

5. ClickNew repository variable.

6. In theName field, enter a name for your variable.

7. In theValue field, enter the value for your variable.

8. ClickAdd variable.

Creating configuration variables for an environment

To create secrets or variables for an environment in a personal account repository, you must be the repository owner. To create secrets or variables for an environment in an organization repository, you must haveadmin access. For more information on environments, seeManaging environments for deployment.

1. On GitHub, navigate to the main page of the repository.

2. Under your repository name, click Settings. If you cannot see the "Settings" tab, select the dropdown menu, then clickSettings.

   

3. In the left sidebar, clickEnvironments.

4. Click on the environment that you want to add a variable to.

5. UnderEnvironment variables, clickAdd variable.

6. In theName field, enter a name for your variable.

7. In theValue field, enter the value for your variable.

8. ClickAdd variable.

Creating configuration variables for an organization

When creating a secret or variable in an organization, you can use a policy to limit access by repository. For example, you can grant access to all repositories, or limit access to only private repositories or a specified list of repositories.

Organization owners can create secrets or variables at the organization level.

1. On GitHub, navigate to the main page of the organization.

2. Under your organization name, click Settings. If you cannot see the "Settings" tab, select the dropdown menu, then clickSettings.

   

3. In the "Security" section of the sidebar, select Secrets and variables, then clickActions.

4. Click theVariables tab.

   

5. ClickNew organization variable.

6. In theName field, enter a name for your variable.

7. In theValue field, enter the value for your variable.

8. From theRepository access dropdown list, choose an access policy.

9. ClickAdd variable.

Using contexts to access variable values

Contexts are a way to access information about workflow runs, variables, runner environments, jobs, and steps. For more information, seeContexts reference. There are many other contexts that you can use for a variety of purposes in your workflows. For details of where you can use specific contexts within a workflow, seeContexts reference.

You can access environment variable values using theenv context and configuration variable values using thevars context.

Using theenv context to access environment variable values

In addition to runner environment variables, GitHub Actions allows you to set and readenv key values using contexts. Environment variables and contexts are intended for use at different points in the workflow.

Therun steps in a workflow, or in a referenced action, are processed by a runner. As a result, you can use runner environment variables here, using the appropriate syntax for the shell you are using on the runner - for example,$NAME for the bash shell on a Linux runner, or$env:NAME for PowerShell on a Windows runner. In most cases you can also use contexts, with the syntax${{ CONTEXT.PROPERTY }}, to access the same value. The difference is that the context will be interpolated and replaced by a string before the job is sent to a runner.

However, you cannot use runner environment variables in parts of a workflow that are processed by GitHub Actions and are not sent to the runner. Instead, you must use contexts. For example, anif conditional, which determines whether a job or step is sent to the runner, is always processed by GitHub Actions. You must therefore use a context in anif conditional statement to access the value of an variable.

name: Conditional env variableon: workflow_dispatchenv:  DAY_OF_WEEK: Mondayjobs:  greeting_job:    runs-on: ubuntu-latest    env:      Greeting: Hello    steps:      - name: "Say Hello Mona it's Monday"        if: ${{ env.DAY_OF_WEEK == 'Monday' }}        run: echo "$Greeting $First_Name. Today is $DAY_OF_WEEK!"        env:          First_Name: Mona

name:Conditionalenvvariableon:workflow_dispatchenv:DAY_OF_WEEK:Mondayjobs:greeting_job:runs-on:ubuntu-latestenv:Greeting:Hellosteps:-name:"Say Hello Mona it's Monday"if:${{env.DAY_OF_WEEK=='Monday'}}run:echo"$Greeting $First_Name. Today is $DAY_OF_WEEK!"env:First_Name:Mona

In this modification of the earlier example, we've introduced anif conditional. The workflow step is now only run ifDAY_OF_WEEK is set to "Monday". We access this value from theif conditional statement by using theenv context. Theenv context is not required for the variables referenced within therun command. They are referenced as runner environment variables and are interpolated after the job is received by the runner. We could, however, have chosen to interpolate those variables before sending the job to the runner, by using contexts. The resulting output would be the same.

run:echo"${{ env.Greeting }} ${{ env.First_Name }}. Today is ${{ env.DAY_OF_WEEK }}!"

Using thevars context to access configuration variable values

Configuration variables can be accessed across the workflow usingvars context. For more information, seeContexts reference.

If a configuration variable has not been set, the return value of a context referencing the variable will be an empty string.

The following example shows using configuration variables with thevars context across a workflow. Each of the following configuration variables have been defined at the repository, organization, or environment levels.

on:  workflow_dispatch:env:  # Setting an environment variable with the value of a configuration variable  env_var: ${{ vars.ENV_CONTEXT_VAR }}jobs:  display-variables:    name: ${{ vars.JOB_NAME }}    # You can use configuration variables with the `vars` context for dynamic jobs    if: ${{ vars.USE_VARIABLES == 'true' }}    runs-on: ${{ vars.RUNNER }}    environment: ${{ vars.ENVIRONMENT_STAGE }}    steps:    - name: Use variables      run: |        echo "repository variable : $REPOSITORY_VAR"        echo "organization variable : $ORGANIZATION_VAR"        echo "overridden variable : $OVERRIDE_VAR"        echo "variable from shell environment : $env_var"      env:        REPOSITORY_VAR: ${{ vars.REPOSITORY_VAR }}        ORGANIZATION_VAR: ${{ vars.ORGANIZATION_VAR }}        OVERRIDE_VAR: ${{ vars.OVERRIDE_VAR }}            - name: ${{ vars.HELLO_WORLD_STEP }}      if: ${{ vars.HELLO_WORLD_ENABLED == 'true' }}      uses: actions/hello-world-javascript-action@main      with:        who-to-greet: ${{ vars.GREET_NAME }}

on:workflow_dispatch:env:# Setting an environment variable with the value of a configuration variableenv_var:${{vars.ENV_CONTEXT_VAR}}jobs:display-variables:name:${{vars.JOB_NAME}}# You can use configuration variables with the `vars` context for dynamic jobsif:${{vars.USE_VARIABLES=='true'}}runs-on:${{vars.RUNNER}}environment:${{vars.ENVIRONMENT_STAGE}}steps:-name:Usevariablesrun:|        echo "repository variable : $REPOSITORY_VAR"        echo "organization variable : $ORGANIZATION_VAR"        echo "overridden variable : $OVERRIDE_VAR"        echo "variable from shell environment : $env_var"env:REPOSITORY_VAR:${{vars.REPOSITORY_VAR}}ORGANIZATION_VAR:${{vars.ORGANIZATION_VAR}}OVERRIDE_VAR:${{vars.OVERRIDE_VAR}}-name:${{vars.HELLO_WORLD_STEP}}if:${{vars.HELLO_WORLD_ENABLED=='true'}}uses:actions/hello-world-javascript-action@mainwith:who-to-greet:${{vars.GREET_NAME}}

Detecting the operating system

You can write a single workflow file that can be used for different operating systems by using theRUNNER_OS default environment variable and the corresponding context property${{ runner.os }}. For example, the following workflow could be run successfully if you changed the operating system frommacos-latest towindows-latest without having to alter the syntax of the environment variables, which differs depending on the shell being used by the runner.

on: workflow_dispatchjobs:  if-Windows-else:    runs-on: macos-latest    steps:      - name: condition 1        if: runner.os == 'Windows'        run: echo "The operating system on the runner is $env:RUNNER_OS."      - name: condition 2        if: runner.os != 'Windows'        run: echo "The operating system on the runner is not Windows, it's $RUNNER_OS."

on:workflow_dispatchjobs:if-Windows-else:runs-on:macos-lateststeps:-name:condition1if:runner.os=='Windows'run:echo"The operating system on the runner is $env:RUNNER_OS."-name:condition2if:runner.os!='Windows'run:echo"The operating system on the runner is not Windows, it's $RUNNER_OS."

In this example, the twoif statements check theos property of therunner context to determine the operating system of the runner.if conditionals are processed by GitHub Actions, and only steps where the check resolves astrue are sent to the runner. Here one of the checks will always betrue and the otherfalse, so only one of these steps is sent to the runner. Once the job is sent to the runner, the step is executed and the environment variable in theecho command is interpolated using the appropriate syntax ($env:NAME for PowerShell on Windows, and$NAME for bash and sh on Linux and macOS). In this example, the statementruns-on: macos-latest means that the second step will be run.

Passing values between steps and jobs in a workflow

If you generate a value in one step of a job, you can use the value in subsequent steps of the same job by assigning the value to an existing or new environment variable and then writing this to theGITHUB_ENV environment file. The environment file can be used directly by an action, or from a shell command in the workflow file by using therun keyword. For more information, seeWorkflow commands for GitHub Actions.

If you want to pass a value from a step in one job in a workflow to a step in another job in the workflow, you can define the value as a job output. You can then reference this job output from a step in another job. For more information, seeWorkflow syntax for GitHub Actions.

Next steps

For reference information, seeVariables reference.