Authenticate to Google Cloud

Authenticate to Google Cloud from GitHub Actions

This GitHub Action authenticates to Google Cloud. It supports authentication via a Google Cloud Service Account Key JSON and authentication via Workload Identity Federation.

Workload Identity Federation is recommended over Service Account Keys as it obviates the need to export a long-lived credential and establishes a trust delegation relationship between a particular GitHub Actions workflow invocation and permissions on Google Cloud. There are three ways to set up this GitHub Action to authenticate to Google Cloud:

(Preferred) Direct Workload Identity Federation
Workload Identity Federation through a Service Account
Service Account Key JSON

This is not an officially supported Google product, and it is not covered by a Google Cloud support contract. To report bugs or request features in a Google Cloud product, please contact Google Cloud support.

Prerequisites

Run the actions/checkout@v4 step before this action. Omitting the checkout step or putting it after auth will cause future steps to be unable to authenticate.
To create binaries, containers, pull requests, or other releases, add the following to your .gitignore to prevent accidentially committing credentials to your release artifact:
```
# Ignore generated credentials from google-github-actions/auth
gha-creds-*.json
```
To use the bq or gsutil tools, use the Google Cloud SDK version 390.0.0 or newer.
This action runs using Node 20. Use a runner version that supports this version of Node or newer.

Usage

jobs:
  job_id:
    # Add "id-token" with the intended permissions.
    permissions:
      contents: 'read'
      id-token: 'write'

    steps:
    - uses: 'actions/checkout@v4'

    - uses: 'google-github-actions/auth@v2'
      with:
        project_id: 'my-project'
        workload_identity_provider: 'projects/123456789/locations/global/workloadIdentityPools/my-pool/providers/my-provider'

⚠️ NOTE! Changing the permissions block may remove some default permissions. See the permissions documentation for more information.

For more usage options, see the examples.

Inputs

Inputs: Workload Identity Federation

⚠️ WARNING! This option is not supported by Firebase Admin SDK. Use Service Account Key JSON authentication instead.

The following inputs are for authenticating to Google Cloud via Workload Identity Federation.

workload_identity_provider: (Required) The full identifier of the Workload Identity Provider, including the project number, pool name, and provider name. If provided, this must be the full identifier which includes all parts:
```
projects/123456789/locations/global/workloadIdentityPools/my-pool/providers/my-provider
```
service_account: (Optional) Email address or unique identifier of the Google Cloud service account for which to impersonate and generate credentials. For example:
```
[email protected]
```
Without this input, the GitHub Action will use Direct Workload Identity Federation. If this input is provided, the GitHub Action will use Workload Identity Federation through a Service Account.
audience: (Optional) The value for the audience (aud) parameter in the generated GitHub Actions OIDC token. This value defaults to the value of workload_identity_provider, which is also the default value Google Cloud expects for the audience parameter on the token.

Inputs: Service Account Key JSON

⚠️ WARNING! Service Account Key JSON credentials are long-lived credentials and must be treated like a password.

The following inputs are for authenticating to Google Cloud via a Service Account Key JSON.

credentials_json: (Required) The Google Cloud Service Account Key JSON to use for authentication.

We advise minifying your JSON into a single line string before storing it in a GitHub Secret. When a GitHub Secret is used in a GitHub Actions workflow, each line of the secret is masked in log output. This can lead to aggressive sanitization of benign characters like curly braces ({}) and brackets ([]).

To generate access tokens or ID tokens using this service account, you must grant the underlying service account roles/iam.serviceAccountTokenCreator permissions on itself.

Inputs: Generating OAuth 2.0 access tokens

The following inputs are for generating OAuth 2.0 access tokens for authenticating to Google Cloud as an output for use in future steps in the workflow. These options only apply to access tokens generated by this action. By default, this action does not generate any tokens.

service_account: (Required) Email address or unique identifier of the Google Cloud service account for which to generate the access token. For example:
```
[email protected]
```
token_format: (Required) This value must be "access_token" to generate OAuth 2.0 access tokens.
access_token_lifetime: (Optional) Desired lifetime duration of the access token, in seconds. This must be specified as the number of seconds with a trailing "s" (e.g. 30s). The default value is 1 hour (3600s). The maximum value is 1 hour, unless the [constraints/iam.allowServiceAccountCredentialLifetimeExtension organization policy][orgpolicy-creds-lifetime] is enabled, in which case the maximum value is 12 hours.
access_token_scopes: (Optional) List of OAuth 2.0 access scopes to be included in the generated token. This is only valid when "token_format" is "access_token". The default value is:
```
https://www.googleapis.com/auth/cloud-platform
```
access_token_subject: (Optional) Email address of a user to impersonate for Domain-Wide Delegation. Access tokens created for Domain-Wide Delegation cannot have a lifetime beyond 1 hour, even if the [constraints/iam.allowServiceAccountCredentialLifetimeExtension organization policy][orgpolicy-creds-lifetime] is enabled.

In order to support Domain-Wide Delegation via Workload Identity Federation, you must grant the external identity ("principalSet") roles/iam.serviceAccountTokenCreator in addition to roles/iam.workloadIdentityUser. The default Workload Identity setup will only grant the latter role. If you want to use this GitHub Action with Domain-Wide Delegation, you must manually add the "Service Account Token Creator" role onto the external identity.

You will also need to customize the access_token_scopes value to correspond to the OAuth scopes required for the API(s) you will access.

Inputs: Generating ID tokens

The following inputs are for generating ID tokens for authenticating to Google Cloud as an output for use in future steps in the workflow. These options only apply to ID tokens generated by this action. By default, this action does not generate any tokens.

service_account: (Required) Email address or unique identifier of the Google Cloud service account for which to generate the ID token. For example:
```
[email protected]
```
token_format: This value must be "id_token" to generate ID tokens.
id_token_audience: (Required) The audience for the generated ID Token.
id_token_include_email: (Optional) Optional parameter of whether to include the service account email in the generated token. If true, the token will contain "email" and "email_verified" claims. This is only valid when "token_format" is "id_token". The default value is false.

Inputs: Retry options

The following inputs are for controlling retry behavior. By default, this GitHub Action will retry API calls in an attempt to reduce transient failures. You can control and disable the retry behavior with these inputs.

retries: (Optional) Number of times to retry a failed authentication attempt. This is useful for automated pipelines that may execute before IAM permissions are fully propogated or intermittent connectivity failures. The default value is "3".
backoff: (Optional) Delay time before trying another authentication attempt. This is implemented using a fibonacci backoff method (e.g. 1-1-2-3-5). This value defaults to 250 milliseconds.
backoff_limit: (Optional) Limits the retry backoff to the specified value. The default value is no limit.

Inputs: Miscellaneous

The following inputs are for controlling the behavior of this GitHub Actions, regardless of the authentication mechanism.

project_id: (Optional) Custom project ID to use for authentication and exporting into other steps. If unspecified, the project ID will be extracted from the Workload Identity Provider or the Service Account Key JSON.
create_credentials_file: (Optional) If true, the action will securely generate a credentials file which can be used for authentication via gcloud and Google Cloud SDKs in other steps in the workflow. The default is true.

The credentials file is exported into $GITHUB_WORKSPACE, which makes it available to all future steps and filesystems (including Docker-based GitHub Actions). The file is automatically removed at the end of the job via a post action. In order to use exported credentials, you must add the actions/checkout step before calling auth. This is due to how GitHub Actions creates $GITHUB_WORKSPACE:
```
jobs:
 job_id:
   steps:
   - uses: 'actions/checkout@v4' # Must come first!
   - uses: 'google-github-actions/auth@v2'
```
export_environment_variables: (Optional) If true, the action will export common environment variables which are known to be consumed by popular downstream libraries and tools, including:
- CLOUDSDK_PROJECT
- CLOUDSDK_CORE_PROJECT
- GCP_PROJECT
- GCLOUD_PROJECT
- GOOGLE_CLOUD_PROJECT
If create_credentials_file is true, additional environment variables are exported:
- CLOUDSDK_AUTH_CREDENTIAL_FILE_OVERRIDE
- GOOGLE_APPLICATION_CREDENTIALS
- GOOGLE_GHA_CREDS_PATH
If false, the action will not export any environment variables, meaning future steps are unlikely to be automatically authenticated to Google Cloud. The default value is true.
delegates: (Optional) List of additional service account emails or unique identities to use for impersonation in the chain. By default there are no delegates.
universe: (Optional) The Google Cloud universe to use for constructing API endpoints. The default universe is "googleapis.com", which corresponds to https://cloud.google.com. Trusted Partner Cloud and Google Distributed Hosted Cloud should set this to their universe address.

You can also override individual API endpoints by setting the environment variable GHA_ENDPOINT_OVERRIDE_<endpoint> where endpoint is the API endpoint to override. This only applies to the auth action and does not persist to other steps. For example:
```
env:
  GHA_ENDPOINT_OVERRIDE_oauth2: 'https://oauth2.myapi.endpoint/v1'
```
cleanup_credentials: (Optional) If true, the action will remove any created credentials from the filesystem upon completion. This only applies if "create_credentials_file" is true. The default is true.

Outputs

project_id: Provided or extracted value for the Google Cloud project ID.
credentials_file_path: Path on the local filesystem where the generated credentials file resides. This is only available if "create_credentials_file" was set to true.
auth_token: The Google Cloud federated token (for Workload Identity Federation) or self-signed JWT (for a Service Account Key JSON). This output is always available.
access_token: The Google Cloud access token for calling other Google Cloud APIs. This is only available when "token_format" is "access_token".
id_token: The Google Cloud ID token. This is only available when "token_format" is "id_token".

Setup

This section describes the three configuration options:

(Preferred) Direct Workload Identity Federation
Workload Identity Federation through a Service Account
Service Account Key JSON

⚠️ NOTE! It can take up to 5 minutes for Workload Identity Pools, Workload Identity Providers, and IAM permissions to propagate. Please wait at least five minutes and follow all Troubleshooting steps before opening an issue.

(Preferred) Direct Workload Identity Federation

In this setup, the Workload Identity Pool has direct IAM permissions on Google Cloud resources; there are no intermediate service accounts or keys. This is preferred since it directly authenticates GitHub Actions to Google Cloud without a proxy resource. However, not all Google Cloud resources support principalSet identities. Please see the documentation for your Google Cloud service for more information.

⚠️ NOTE! To generate OAuth 2.0 access tokens or ID tokens, you must provide a service account email, and the Workload Identity Pool must have roles/iam.workloadIdentityUser permissions on the target Google Cloud Service Account. Follow the steps for Workload Identity Federation through a Service Account instead.

Click here to show detailed instructions for configuring GitHub authentication to Google Cloud via a direct Workload Identity Federation.

These instructions use the gcloud command-line tool.

Create a Workload Identity Pool:

gcloud iam workload-identity-pools create "github" \
  --project="${PROJECT_ID}" \
  --location="global" \
  --display-name="GitHub Actions Pool"

Get the full ID of the Workload Identity Pool:

gcloud iam workload-identity-pools describe "github" \
  --project="${PROJECT_ID}" \
  --location="global" \
  --format="value(name)"

This value should be of the format:

projects/123456789/locations/global/workloadIdentityPools/github

Create a Workload Identity Provider in that pool:
```
gcloud iam workload-identity-pools providers create-oidc "my-repo" \
  --project="${PROJECT_ID}" \
  --location="global" \
  --workload-identity-pool="github" \
  --display-name="My GitHub repo Provider" \
  --attribute-mapping="google.subject=assertion.sub,attribute.actor=assertion.actor,attribute.repository=assertion.repository" \
  --issuer-uri="https://token.actions.githubusercontent.com"
```
The attribute mappings map claims in the GitHub Actions JWT to assertions you can make about the request (like the repository or GitHub username of the principal invoking the GitHub Action). These can be used to further restrict the authentication using --attribute-condition flags.

❗️ NOTE! You must map any claims in the incoming token to attributes before you can assert on those attributes in a CEL expression or IAM policy!**
Extract the Workload Identity Provider resource name:
```
gcloud iam workload-identity-pools providers describe "my-repo" \
  --project="${PROJECT_ID}" \
  --location="global" \
  --workload-identity-pool="github" \
  --format="value(name)"
```
Use this value as the workload_identity_provider value in the GitHub Actions YAML:
```
- uses: 'google-github-actions/auth@v2'
  with:
    project_id: 'my-project'
    workload_identity_provider: '...' # "projects/123456789/locations/global/workloadIdentityPools/github/providers/my-repo"
```
⚠️ NOTE! The project_id input is optional, but may be required by downstream authentication systems such as the gcloud CLI. Unfortunately we cannot extract the project ID from the Workload Identity Provider, since it requires the project number.

It is technically possible to convert a project number into a project ID, but it requires permissions to call Cloud Resource Manager, and we cannot guarantee that the Workload Identity Pool has those permissions.
As needed, allow authentications from the Workload Identity Pool to Google Cloud resources. These can be any Google Cloud resources that support federated ID tokens, and it can be done after the GitHub Action is configured.

The following example shows granting access from a GitHub Action in a specific repository a secret in Google Secret Manager.
```
# TODO(developer): Update this value to your GitHub repository.
export REPO="username/name" # e.g. "google/chrome"
export WORKLOAD_IDENTITY_POOL_ID="value/from/above" # e.g. "projects/123456789/locations/global/workloadIdentityPools/github"

gcloud secrets add-iam-policy-binding "my-secret" \
  --project="${PROJECT_ID}" \
  --role="roles/secretmanager.secretAccessor" \
  --member="principalSet://iam.googleapis.com/${WORKLOAD_IDENTITY_POOL_ID}/attribute.repository/${REPO}"
```
Review the GitHub documentation for a complete list of options and values. This GitHub repository does not seek to enumerate every possible combination.

Workload Identity Federation through a Service Account

In this setup, the Workload Identity Pool impersonates a Google Cloud Service Account which has IAM permissions on Google Cloud resources. This exchanges the GitHub Actions OIDC token with a Google Cloud OAuth 2.0 access token by granting GitHub Actions permissions to mint tokens for the given Service Account. Thus GitHub Actions inherits that Service Account's permissions by proxy.

Click here to show detailed instructions for configuring GitHub authentication to Google Cloud via a Workload Identity Federation through a Service Account.

These instructions use the gcloud command-line tool.

(Optional) Create a Google Cloud Service Account. If you already have a Service Account, take note of the email address and skip this step.
```
gcloud iam service-accounts create "my-service-account" \
  --project "${PROJECT_ID}"
```

Create a Workload Identity Pool:

gcloud iam workload-identity-pools create "github" \
  --project="${PROJECT_ID}" \
  --location="global" \
  --display-name="GitHub Actions Pool"

Get the full ID of the Workload Identity Pool:

gcloud iam workload-identity-pools describe "github" \
  --project="${PROJECT_ID}" \
  --location="global" \
  --format="value(name)"

This value should be of the format:

projects/123456789/locations/global/workloadIdentityPools/github

Create a Workload Identity Provider in that pool:
```
gcloud iam workload-identity-pools providers create-oidc "my-repo" \
  --project="${PROJECT_ID}" \
  --location="global" \
  --workload-identity-pool="github" \
  --display-name="My GitHub repo Provider" \
  --attribute-mapping="google.subject=assertion.sub,attribute.actor=assertion.actor,attribute.repository=assertion.repository" \
  --issuer-uri="https://token.actions.githubusercontent.com"
```
The attribute mappings map claims in the GitHub Actions JWT to assertions you can make about the request (like the repository or GitHub username of the principal invoking the GitHub Action). These can be used to further restrict the authentication using --attribute-condition flags.

❗️ NOTE! You must map any claims in the incoming token to attributes before you can assert on those attributes in a CEL expression or IAM policy!**

Allow authentications from the Workload Identity Pool to your Google Cloud Service Account.

# TODO(developer): Update this value to your GitHub repository.
export REPO="username/name" # e.g. "google/chrome"
export WORKLOAD_IDENTITY_POOL_ID="value/from/above" # e.g. "projects/123456789/locations/global/workloadIdentityPools/github"

gcloud iam service-accounts add-iam-policy-binding "my-service-account@${PROJECT_ID}.iam.gserviceaccount.com" \
  --project="${PROJECT_ID}" \
  --role="roles/iam.workloadIdentityUser" \
  --member="principalSet://iam.googleapis.com/${WORKLOAD_IDENTITY_POOL_ID}/attribute.repository/${REPO}"

Review the GitHub documentation for a complete list of options and values. This GitHub repository does not seek to enumerate every possible combination.

Extract the Workload Identity Provider resource name:

gcloud iam workload-identity-pools providers describe "my-repo" \
  --project="${PROJECT_ID}" \
  --location="global" \
  --workload-identity-pool="github" \
  --format="value(name)"

Use this value as the workload_identity_provider value in the GitHub Actions YAML:

- uses: 'google-github-actions/auth@v2'
  with:
    workload_identity_provider: '...' # "projects/123456789/locations/global/workloadIdentityPools/github/providers/my-repo"

As needed, grant the Google Cloud Service Account permissions to access Google Cloud resources. This step varies by use case. The following example shows granting access to a secret in Google Secret Manager.

gcloud secrets add-iam-policy-binding "my-secret" \
  --project="${PROJECT_ID}" \
  --role="roles/secretmanager.secretAccessor" \
  --member="serviceAccount:my-service-account@${PROJECT_ID}.iam.gserviceaccount.com"

Service Account Key JSON

In this setup, a Service Account has direct IAM permissions on Google Cloud resources. You download a Service Account Key JSON file and upload it to GitHub as a secret.

❗️ WARNING! Google Cloud Service Account Key JSON files must be secured and treated like a password. Anyone with acess to the JSON key can authenticate to Google Cloud as the underlying Service Account. By default, these credentials never expire, which is why the former authentication options are much preferred.

Click here to show detailed instructions for configuring GitHub authentication to Google Cloud via a Service Account Key JSON.

These instructions use the gcloud command-line tool.

(Optional) Create a Google Cloud Service Account. If you already have a Service Account, take note of the email address and skip this step.
```
gcloud iam service-accounts create "my-service-account" \
  --project "${PROJECT_ID}"
```

Create a Service Account Key JSON for the Service Account.

gcloud iam service-accounts keys create "key.json" \
  --iam-account "my-service-account@${PROJECT_ID}.iam.gserviceaccount.com"

Upload the contents of this file as a GitHub Actions Secret.

Use the name of the GitHub Actios secret as the credentials_json value in the GitHub Actions YAML:

- uses: 'google-github-actions/auth@v2'
  with:
    credentials_json: '${{ secrets.GOOGLE_CREDENTIALS }}' # Replace with the name of your GitHub Actions secret

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Authenticate to Google Cloud