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Variables reference

Find information for supported variables, naming conventions, limits, and contexts in GitHub Actions workflows.

In this article

This article lists the supported variables you can use in GitHub Actions workflows, including environment variables, configuration variables, and default variables provided by GitHub. Use this reference to look up variable names, naming conventions, limits, and supported contexts when configuring your workflows.

For more information about variables, see Variables.

Default environment variables

The default environment variables that GitHub sets are available to every step in a workflow.

Because default environment variables are set by GitHub and not defined in a workflow, they are not accessible through the env context. However, most of the default variables have a corresponding, and similarly named, context property. For example, the value of the GITHUB_REF variable can be read during workflow processing using the ${{ github.ref }} context property.

You can't overwrite the value of the default environment variables named GITHUB_* and RUNNER_*. Currently you can overwrite the value of the CI variable. However, it's not guaranteed that this will always be possible. For more information about setting environment variables, see Store information in variables and Workflow commands for GitHub Actions.

We strongly recommend that actions use variables to access the filesystem rather than using hardcoded file paths. GitHub sets variables for actions to use in all runner environments.

VariableDescription
CIAlways set to true.
GITHUB_ACTIONThe name of the action currently running, or the id of a step. For example, for an action, __repo-owner_name-of-action-repo.

GitHub removes special characters, and uses the name __run when the current step runs a script without an id. If you use the same script or action more than once in the same job, the name will include a suffix that consists of the sequence number preceded by an underscore. For example, the first script you run will have the name __run, and the second script will be named __run_2. Similarly, the second invocation of actions/checkout will be actionscheckout2.
GITHUB_ACTION_PATHThe path where an action is located. This property is only supported in composite actions. You can use this path to change directories to where the action is located and access other files in that same repository. For example, /home/runner/work/_actions/repo-owner/name-of-action-repo/v1.
GITHUB_ACTION_REPOSITORYFor a step executing an action, this is the owner and repository name of the action. For example, actions/checkout.
GITHUB_ACTIONSAlways set to true when GitHub Actions is running the workflow. You can use this variable to differentiate when tests are being run locally or by GitHub Actions.
GITHUB_ACTORThe name of the person or app that initiated the workflow. For example, octocat.
GITHUB_ACTOR_IDThe account ID of the person or app that triggered the initial workflow run. For example, 1234567. Note that this is different from the actor username.
GITHUB_API_URLReturns the API URL. For example: http(s)://HOSTNAME/api/v3.
GITHUB_BASE_REFThe name of the base ref or target branch of the pull request in a workflow run. This is only set when the event that triggers a workflow run is either pull_request or pull_request_target. For example, main.
GITHUB_ENVThe path on the runner to the file that sets variables from workflow commands. The path to this file is unique to the current step and changes for each step in a job. For example, /home/runner/work/_temp/_runner_file_commands/set_env_87406d6e-4979-4d42-98e1-3dab1f48b13a. For more information, see Workflow commands for GitHub Actions.
GITHUB_EVENT_NAMEThe name of the event that triggered the workflow. For example, workflow_dispatch.
GITHUB_EVENT_PATHThe path to the file on the runner that contains the full event webhook payload. For example, /github/workflow/event.json.
GITHUB_GRAPHQL_URLReturns the GraphQL API URL. For example: http(s)://HOSTNAME/api/graphql.
GITHUB_HEAD_REFThe head ref or source branch of the pull request in a workflow run. This property is only set when the event that triggers a workflow run is either pull_request or pull_request_target. For example, feature-branch-1.
GITHUB_JOBThe job_id of the current job. For example, greeting_job.
GITHUB_OUTPUTThe path on the runner to the file that sets the current step's outputs from workflow commands. The path to this file is unique to the current step and changes for each step in a job. For example, /home/runner/work/_temp/_runner_file_commands/set_output_a50ef383-b063-46d9-9157-57953fc9f3f0. For more information, see Workflow commands for GitHub Actions.
GITHUB_PATHThe path on the runner to the file that sets system PATH variables from workflow commands. The path to this file is unique to the current step and changes for each step in a job. For example, /home/runner/work/_temp/_runner_file_commands/add_path_899b9445-ad4a-400c-aa89-249f18632cf5. For more information, see Workflow commands for GitHub Actions.
GITHUB_REFThe fully-formed ref of the branch or tag that triggered the workflow run. For workflows triggered by push, this is the branch or tag ref that was pushed. For workflows triggered by pull_request, this is the pull request merge branch. For workflows triggered by release, this is the release tag created. For other triggers, this is the branch or tag ref that triggered the workflow run. This is only set if a branch or tag is available for the event type. The ref given is fully-formed, meaning that for branches the format is refs/heads/<branch_name>. For pull requests events except pull_request_target, it is refs/pull/<pr_number>/merge. pull_request_target events have the ref from the base branch. For tags it is refs/tags/<tag_name>. For example, refs/heads/feature-branch-1.
GITHUB_REF_NAMEThe short ref name of the branch or tag that triggered the workflow run. This value matches the branch or tag name shown on GitHub. For example, feature-branch-1.

For pull requests, the format is <pr_number>/merge.
GITHUB_REF_PROTECTEDtrue if branch protections are configured for the ref that triggered the workflow run.
GITHUB_REF_TYPEThe type of ref that triggered the workflow run. Valid values are branch or tag.
GITHUB_REPOSITORYThe owner and repository name. For example, octocat/Hello-World.
GITHUB_REPOSITORY_IDThe ID of the repository. For example, 123456789. Note that this is different from the repository name.
GITHUB_REPOSITORY_OWNERThe repository owner's name. For example, octocat.
GITHUB_REPOSITORY_OWNER_IDThe repository owner's account ID. For example, 1234567. Note that this is different from the owner's name.
GITHUB_RETENTION_DAYSThe number of days that workflow run logs and artifacts are kept. For example, 90.
GITHUB_RUN_ATTEMPTA unique number for each attempt of a particular workflow run in a repository. This number begins at 1 for the workflow run's first attempt, and increments with each re-run. For example, 3.
GITHUB_RUN_IDA unique number for each workflow run within a repository. This number does not change if you re-run the workflow run. For example, 1658821493.
GITHUB_RUN_NUMBERA unique number for each run of a particular workflow in a repository. This number begins at 1 for the workflow's first run, and increments with each new run. This number does not change if you re-run the workflow run. For example, 3.
GITHUB_SERVER_URLThe URL of the GitHub server. For example: https://HOSTNAME.
GITHUB_SHAThe commit SHA that triggered the workflow. The value of this commit SHA depends on the event that triggered the workflow. For more information, see Events that trigger workflows. For example, ffac537e6cbbf934b08745a378932722df287a53.
GITHUB_STEP_SUMMARYThe path on the runner to the file that contains job summaries from workflow commands. The path to this file is unique to the current step and changes for each step in a job. For example, /home/runner/_layout/_work/_temp/_runner_file_commands/step_summary_1cb22d7f-5663-41a8-9ffc-13472605c76c. For more information, see Workflow commands for GitHub Actions.
GITHUB_TRIGGERING_ACTORThe username of the user that initiated the workflow run. If the workflow run is a re-run, this value may differ from github.actor. Any workflow re-runs will use the privileges of github.actor, even if the actor initiating the re-run (github.triggering_actor) has different privileges.
GITHUB_WORKFLOWThe name of the workflow. For example, My test workflow. If the workflow file doesn't specify a name, the value of this variable is the full path of the workflow file in the repository.
GITHUB_WORKFLOW_REFThe ref path to the workflow. For example, octocat/hello-world/.github/workflows/my-workflow.yml@refs/heads/my_branch.
GITHUB_WORKFLOW_SHAThe commit SHA for the workflow file.
GITHUB_WORKSPACEThe default working directory on the runner for steps, and the default location of your repository when using the checkout action. For example, /home/runner/work/my-repo-name/my-repo-name.
RUNNER_ARCHThe architecture of the runner executing the job. Possible values are X86, X64, ARM, or ARM64.
RUNNER_DEBUGThis is set only if debug logging is enabled, and always has the value of 1. It can be useful as an indicator to enable additional debugging or verbose logging in your own job steps.
RUNNER_ENVIRONMENTThe environment of the runner executing the job. Possible values are: github-hosted for GitHub-hosted runners provided by GitHub, and self-hosted for self-hosted runners configured by the repository owner.
RUNNER_NAMEThe name of the runner executing the job. This name may not be unique in a workflow run as runners at the repository and organization levels could use the same name. For example, Hosted Agent
RUNNER_OSThe operating system of the runner executing the job. Possible values are Linux, Windows, or macOS. For example, Windows
RUNNER_TEMPThe path to a temporary directory on the runner. This directory is emptied at the beginning and end of each job. Note that files will not be removed if the runner's user account does not have permission to delete them. For example, D:\a\_temp
RUNNER_TOOL_CACHEThe path to the directory containing preinstalled tools for GitHub-hosted runners. For more information, see Using GitHub-hosted runners. For example, C:\hostedtoolcache\windows

Note

If you need to use a workflow run's URL from within a job, you can combine these variables: $GITHUB_SERVER_URL/$GITHUB_REPOSITORY/actions/runs/$GITHUB_RUN_ID

Naming conventions for configuration variables

The following rules apply to configuration variable names:

  • Can only contain alphanumeric characters ([a-z], [A-Z], [0-9]) or underscores (_). Spaces are not allowed.
  • Must not start with the GITHUB_ prefix.
  • Must not start with a number.
  • Are case insensitive when referenced. GitHub stores secret names as uppercase regardless of how they are entered.
  • Must be unique to the repository, organization, or enterprise where they are created.

Naming conventions for environment variables

When you set an environment variable, you cannot use any of the default environment variable names. For a complete list of default environment variables, see Variables reference below. If you attempt to override the value of one of these default variables, the assignment is ignored.

Note

You can list the entire set of environment variables that are available to a workflow step by using run: env in a step and then examining the output for the step.

Configuration variable precedence

If a variable with the same name exists at multiple levels, the variable at the lowest level takes precedence. For example, if an organization-level variable has the same name as a repository-level variable, then the repository-level variable takes precedence. Similarly, if an organization, repository, and environment all have a variable with the same name, the environment-level variable takes precedence.

For reusable workflows, the variables from the caller workflow's repository are used. Variables from the repository that contains the called workflow are not made available to the caller workflow.

Limits for configuration variables

Individual variables are limited to 48 KB in size.

You can store up to 1,000 organization variables, 500 variables per repository, and 100 variables per environment. The total combined size limit for organization and repository variables is 10 MB per workflow run.

A workflow created in a repository can access the following number of variables:

  • Up to 500 repository variables, if the total size of repository variables is less than 10 MB. If the total size of repository variables exceeds 10 MB, only the repository variables that fall below the limit will be available (as sorted alphabetically by variable name).
  • Up to 1,000 organization variables, if the total combined size of repository and organization variables is less than 10 MB. If the total combined size of organization and repository variables exceeds 10 MB, only the organization variables that fall below that limit will be available (after accounting for repository variables and as sorted alphabetically by variable name).
  • Up to 100 environment-level variables.

Note

Environment-level variables do not count toward the 10 MB total size limit. If you exceed the combined size limit for repository and organization variables and still need additional variables, you can use an environment and define additional variables in the environment.

Supported contexts

You will commonly use either the env or github context to access variable values in parts of the workflow that are processed before jobs are sent to runners.

Warning

Do not print the github context to logs. It contains sensitive information.

ContextUse caseExample
envReference custom variables defined in the workflow.${{ env.MY_VARIABLE }}
githubReference information about the workflow run and the event that triggered the run.${{ github.repository }}