Access control with IAM

You can set access control using roles at the project level. Grant a role to a project member or service account to determine the level of access to your Google Cloud project and its resources. By default, all Cloud projects come with a single user: the original project creator. No other users have access to the project, and therefore, access to functions, until a user is added as a project team member.

Access control for users

You can add users as team members to your project and grant them roles using Identity and Access Management (IAM).

Cloud Functions supports the basic roles of Editor, Owner, and Viewer, which give the following permissions:

  • Editor and Owner: Read and write access to all functions-related resources. Lets users deploy, update, and delete functions. Additional access to other resources in the project.
  • Viewer: Read-only access to functions and locations. Lets users list functions and see their details, but does not let them view the source code. Additional access to other resources in the project.

Cloud Functions also supports the Cloud Functions predefined Developer and Viewer roles, which give the following permissions:

  • Developer: Read and write access to all functions-related resources. Lets users deploy, update, and delete functions. No access to other resources in the project.
  • Viewer: Read-only access to functions and locations. Lets users list functions and see their details, but does not let them view the source code. No access to other resources in the project.

Access control for service accounts

A service account is a special type of Google Cloud account that acts as an identity for a non-human user that needs to authenticate and be authorized to access data and perform various actions. Some of these accounts are created and managed by Google itself and are known as service agents.

The following service accounts are used for all Cloud Functions runtimes:

Name Member ID Role
App Engine default service account PROJECT_ID@appspot.gserviceaccount.com Editor
Google Cloud Functions Service Agent service-PROJECT_NUMBER@gcf-admin-robot.iam.gserviceaccount.com Cloud Functions Service Agent

In addition, for all runtimes except Node.js 8 and Go 1.11, the following service accounts are required:

Name Member ID Role
PROJECT_NUMBER@cloudbuild.gserviceaccount.com Cloud Build Service Account
Cloud Build Service Account service-PROJECT_NUMBER@gcp-sa-cloudbuild.iam.gserviceaccount.com Cloud Build Service Agent
Google Container Registry Service Agent service-PROJECT_NUMBER@containerregistry.iam.gserviceaccount.com Container Registry Service Agent

Runtime service accounts

At runtime, Cloud Functions defaults to using the App Engine default service account (PROJECT_ID@appspot.gserviceaccount.com), which has the Editor role on the project. You can change the roles of this service account to limit or extend the permissions for your running functions. You can also change which service account is used by providing a non-default individual service account.

To learn more about service accounts, see the service accounts documentation.

Administrative service accounts

To perform administrative actions on your project during the creation, updating, or deletion of functions, all projects in Cloud Functions require the Google Cloud Functions Service Agent service account (service-PROJECT_NUMBER@gcf-admin-robot.iam.gserviceaccount.com).

In addition, all runtimes except Node.js 8 and Go 1.11 carry out container image building and storage within your project. In this case, you also need to provision the following:

These service accounts should have the roles listed in the earlier table.

Google Cloud Functions Service Agent service account

By default, the Google Cloud Functions Service Agent service account (service-PROJECT_NUMBER@gcf-admin-robot.iam.gserviceaccount.com has the cloudfunctions.serviceAgent role on your project. Creating, updating, and deleting functions might fail if you change this account's permissions.

The cloudfunctions.serviceAgent role has the following permissions:

Permission Description
pubsub.subscriptions.* Manage subscriptions in the user's project.
pubsub.topics.create Create a new topic once a function is deployed.
pubsub.topics.attachSubscription Attach subscription to an existing topic.
pubsub.topics.get Get the existing topic on which the function should be triggered.
pubsub.subscriptions.get Get the subscription that triggers the function.
pubsub.topics.list Required for checking the existence of a Pub/Sub topic.
iam.serviceAccounts.{getAccessToken, signBlob} Ability to get runtime service account credentials.
iam.serviceAccounts.getOpenIdToken Needed for the agent to get an OpenID token on a user-specified authority. OpenID token is used for invoking IAM-enabled functions.
resourcemanager.projects.get Get the project details.
resourcemanager.projects.getIamPolicy Determine the function origin.
firebasedatabase.instances.{get, update} Create functions triggered by the Firebase Realtime Database.
storage.buckets.{get, update} Configure notifications on a Cloud Storage bucket that trigger a function.
storage.buckets.create,
storage.objects.{delete, get, create, list}
Required for storing source code in user project.
clientauthconfig.clients.list List OAuth clients of the project for an IAM-guarded HTTP function.
cloudfunctions.functions.invoke Invoke an IAM-guarded HTTP function.
compute.globalOperations.get,
compute.networks.access,
vpcaccess.connectors.{get, use}
Provision functions with access to the consumer projects VPC.
cloudbuild.customworkers.builder Create builds in Cloud Build custom workers.
cloudbuild.builds.editor,
serviceusage.services.use
Required to use Cloud Build to perform builds in user project.

You can reset this service account to the default role by removing whatever role it currently has and adding the Cloud Functions Service Agent role:

gcloud projects add-iam-policy-binding PROJECT_ID \
  --member serviceAccount:service-PROJECT_NUMBER@gcf-admin-robot.iam.gserviceaccount.com \
  --role roles/cloudfunctions.serviceAgent

Troubleshooting permission errors

If you get permission errors when you deploy, update, delete, or execute functions in your project, perform the following steps:

  1. Make sure that you have the Editor or Owner role on your project, or that you are using the Cloud Functions Developer role.

    If you are using the Cloud Functions Developer role, also ensure that you have granted the user the IAM Service Account User role.

  2. Verify that the Cloud Functions Service Agent service account (service-PROJECT_NUMBER@gcf-admin-robot.iam.gserviceaccount.com) has the cloudfunctions.serviceAgent role for your project.

    Make sure the Include Google-provided role grants box on the Permissions tab of the Console IAM page is checked to see this account. Or you can use gcloud projects add-iam-policy-binding PROJECT_ID.

  3. Ensure that you have permissions for trigger sources, such as Pub/Sub or Cloud Storage.

If you get an ”insufficient permissions” error, or have other authentication problems when you run your functions, make sure that the runtime service account has the correct permissions to access the resources your functions need. Then, repeat steps 2 and 3.

If you get a ”service unavailable” error during deployment, make sure that the runtime service account PROJECT_ID@appspot.gserviceaccount.com exists in your project. To recreate this service account if it was deleted, see Undeleting a service account.

See also Troubleshooting Cloud Functions.