# Google Cloud Build

## Steps to Setup Google Cloud Build <a href="#steps-to-setup-google-cloud-build" id="steps-to-setup-google-cloud-build"></a>

* This (Cloud Build) is a service that executes builds on GCP infrastructure. Cloud Build can import source code from GCS, Cloud Storage Repo’s, GitHub or BitBucket and execute a build as per the configurations and provide artifacts such as Java archives or docker containers.
* Using this CI system on Spinnaker, enables Spinnaker to trigger pipelines upon completion on builds.
* **Prerequisites**:
  1. Ensure to have a valid GCP with a Cloud Build API. API can be enabled with the gcloud command as below

     ```
     gcloud services enable cloudbuild.googleapis.com
     ```
* **Configure Spinnaker for Google Cloud Build Pub/Sub Notifications:**
* Google Cloud Build sends [Build Notifications](https://cloud.google.com/cloud-build/docs/send-build-notifications) when the state of your build changes. Create a pipeline trigger to invoke a pipeline based on the status of your build.
  1. Create a Subscription Object for the cloud-builds topics in your project

     ```
     PROJECT_ID=
     SUBSCRIPTION_NAME=googleCloudBuilds

     gcloud pubsub subscriptions create $SUBSCRIPTION_NAME \
     --topic projects/$PROJECT_ID/topics/cloud-builds \
     --project $PROJECT_ID
     ```
  2. Configure Google Cloud Build for Spinnaker, using Halyard by executing the following command

     ```
     hal config pubsub google subscription add $SUBSCRIPTION_NAME \
     --project $PROJECT_ID \
     --subscription-name $SUBSCRIPTION_NAME \
     --message-format GCB

     hal config pubsub google enable
     ```
  3. Deploy Spinnaker post execute Steps #1 & #2

     ```
     hal deploy apply
     ```
  4. Steps to Configure Google Cloud Build Pipeline
     * In your Pipeline configuration, click the Configuration stage on the far left of the pipeline.
     * Click Automated Triggers.
     * In the Type field, select Pub/Sub.
     * In the Pub/Sub System Type field, select google.
     * In the Subscription Name field, select your $SUBSCRIPTION\_NAME value.
     * In the Attribute Constraints field, enter status in the Key, and SUCCESS (all upper case) in the Value field.
     * In the Payload Constraints field, you can enter any of the top-level fields from the Build object documentation as the key, and a Java regular expression as the value.
     * In the Expected Artifacts field, you can add any build artifacts as expected artifacts. For example, if the build produces a Docker image, you can add an expected artifact of type Docker with a value of [gcr.io/my-project-id/my-](http://gcr.io/my-project-id/my-) application:tag (replacing my-project-id, my-application, and tag with appropriate values). You can then use the produced image in downstream stages.