Base Image

This directory contains the source code for the base Docker image used by other functions.

Architectural Choice: Cloud Build Substitutions

The cloudbuild.yaml file in this directory uses default substitutions that are overridden by the main Terraform configuration. This allows for a clean separation of concerns, where the cloudbuild.yaml defines the build steps and the main Terraform configuration provides the environment-specific values.

The default substitutions are defined in the substitutions block in the cloudbuild.yaml file. These values are placeholders that are replaced by the actual values from the main Terraform configuration during the build.

The main Terraform configuration passes the actual values for the substitutions in the google_cloudbuild_trigger resource for the base image. This is done in the terraform/cloud_build_triggers.tf file.

This approach allows for the following benefits:

• Separation of concerns: The cloudbuild.yaml file is only responsible for defining the build steps, and the main Terraform configuration is only responsible for providing the environment-specific values.
• Reusability: The cloudbuild.yaml file can be reused for different environments without any modifications.
• Testability: The cloudbuild.yaml file can be tested locally without having to deploy the entire infrastructure.