This article will give you a basic introduction of Cloud Build and a small practical of how it works.

What is Cloud Build?

• Cloud Build is a service that executes your builds on Google Cloud Platform's infrastructure
• You can write a build config to provide instructions to Cloud Build on what tasks to perform.
• A build config file contains instructions for Cloud Build to perform tasks based on your specifications.

Build steps

• Build steps are analogous to commands in a script and provide you with the flexibility of executing arbitrary instructions in your build.
• A build step specifies an action that you want Cloud Build to perform.
• For each build step, Cloud Build executes a docker container as an instance of docker run.
• You can include up to 100 build steps in your config file.
• Example of the build step.
  • Here we have defined steps in which we are calling hashicorp container and running terraform init, plan and apply commands.

  steps:
  - name: hashicorp/terraform
    dir: deployments/
    args: ['init']
  - name: hashicorp/terraform
    dir: deployments/
    args: ['plan','-out=terraform.tfplan']
  - name: hashicorp/terraform
    dir: deployments/
    args: ['apply','-auto-approve']

Hands-on

Creating a cloud build trigger to deploy a storage bucket using terraform. Every time you push to your github repo, trigger will get executed.

Requirements

1) GCP Project 2) Github or Bitbucket repo- You can clone from here

Steps

• Enable cloud build API in your GCP project. Once you enable the API, you will be able to see a cloud build service account in the IAM section. Naming convention of service account is YOUR_PROJECT_NUMBER@cloudbuild.gserviceacco..
• Cloud build will use this service account to create resources on GCP. So it needs to have storage admin permission as we are creating a storage bucket.
• Connect your github repo to cloud source repositories.
  • Open Source repo.
  • Click on Add a repository and select connect to external repository.

• Under Cloud build section on portal, click on create a trigger and fill the form.
  • Name - Name of the trigger
  • Event - Push to a branch
  • Source
    • Repository - Connected GIthub or bitbucket repo
    • Branch - select branch name
  • Configuration
    • Type - Autodected or Cloud Build configuration file (yaml or json)
    • Location - Repository as the yaml is in the repo

• Create the trigger. Now in main.tf change the bucket name and commit.

• Once you commit, cloud build trigger will get executed.You can check live logs and see a GCS bucket got created.