能否在一个Google Cloud Project中为另一项目的Cloud Source Repository创建Cloud Build trigger？

Absolutely! You can set up a Cloud Build trigger in one Google Cloud Project (let’s call this the build project) that targets a Cloud Source Repository (CSR) hosted in a separate GCP project (the repo project). Here’s a straightforward, step-by-step guide to make this work smoothly:

1. First, configure critical IAM permissions #

Cross-project access lives or dies by proper IAM setup—don’t skip this step to avoid frustrating permission errors later:

• In the repo project (where your Cloud Source Repository is stored), grant the Cloud Build service account of your build project the roles/source.reader (Cloud Source Repository Reader) role. This lets the trigger pull code from the external repo.

  To find your build project’s Cloud Build service account: It follows the format [PROJECT_NUMBER]@cloudbuild.gserviceaccount.com. Grab the project number from your build project’s GCP Console settings page.

• Ensure the same service account has roles/cloudbuild.editor (or a higher role like roles/cloudbuild.admin) in your build project—this is usually enabled by default, but double-check if you’ve modified IAM settings in the past.

2. Create the trigger via GCP Console #

If you prefer a graphical approach:

• Navigate to the Cloud Build > Triggers page in your build project’s GCP Console.
• Click Create trigger.
• Under the Repository section, select Connect repository, then choose Cloud Source Repository.
• Click Select another project, enter the ID of your repo project, pick the target repository from the dropdown, and hit Connect.
• Configure the rest of your trigger details:
  • Choose the event type (e.g., push to a branch, tag creation).
  • Set branch/tag patterns (e.g., ^main$ to trigger only on pushes to the main branch).
  • Specify your build configuration file (like cloudbuild.yaml)—this file can live directly in the external repo.
• Review your settings and click Create to finalize the trigger.

3. Create the trigger via gcloud CLI #

For automation or scripted workflows, use the gcloud command-line tool:

1. First, set your active project to the build project:

   gcloud config set project YOUR_BUILD_PROJECT_ID
   

2. Run the trigger creation command, explicitly specifying the repo project and target repository:

   gcloud builds triggers create cloud-source-repositories \
     --name=cross-project-repo-trigger \
     --repo=YOUR_REPO_NAME \
     --repo-project=YOUR_REPO_PROJECT_ID \
     --branch-pattern=^main$ \
     --build-config=cloudbuild.yaml
   

   Adjust parameters like --branch-pattern or --tag-pattern to match your desired trigger conditions.

Quick Notes #

• All build resources (compute instances, logs, etc.) will run in your build project, so billing will be charged to that project.
• If you hit "permission denied" errors during trigger execution, circle back to verify the IAM roles assigned to the Cloud Build service account in both projects.

内容的提问来源于stack exchange，提问作者Mangesh Borade