☁️ GCP Terraform Generator

This module provides a Cloudhopper generator for deploying annotated Java functions as Google Cloud Functions (HTTP-triggered) using Terraform.

It is used by the Cloudhopper annotation processor to generate:

GCP-specific Java handler classes
Terraform infrastructure resources
Supporting metadata for integration and deployment

📦 How to Use

To use this generator in your own project, follow these steps:

1. Add the Maven dependency

<dependency>
  <groupId>eu.cloudhopper.mc</groupId>
  <artifactId>generator-gcp-terraform</artifactId>
  <version>${cloudhopper.version}</version>
</dependency>

2. Configure the annotation processor

<plugin>
  <artifactId>maven-compiler-plugin</artifactId>
  <version>3.8.1</version>
  <configuration>
    <source>17</source>
    <target>17</target>
    <encoding>UTF-8</encoding>
    <annotationProcessors>
      <annotationProcessor>
        eu.cloudhopper.mc.deployment.config.generator.ServerlessFunctionProcessor
      </annotationProcessor>
    </annotationProcessors>
    <compilerArgs>
      <arg>-Acloudprovider=gcp</arg>
      <arg>-AgeneratorId=gcp-terraform</arg>
      <arg>-AconfigOutputDir=${project.build.directory}/deployment/gcp</arg>
      <arg>-AtargetDir=${project.build.directory}</arg>
      <arg>-AartifactId=${project.artifactId}</arg>
      <arg>-Aversion=${project.version}</arg>
      <arg>-Aclassifier=gcp</arg>
    </compilerArgs>
  </configuration>
</plugin>

This configuration ensures that the correct templates are applied and the output is structured for GCP.

📁 Templates

Templates for this generator are located at:

src/main/resources/templates/gcp/

Template	Output Type	Description
`function.ftl`	Terraform	Defines GCP Cloud Function resource
`api.ftl`	Terraform	API Gateway or routing proxy configuration
`apiIntegration.ftl`	Terraform	Binds function with GCP API Gateway (if needed)
`schedule.ftl`	Terraform	Scheduled (cron) job configuration via Cloud Scheduler
`handler.ftl`	Java	Generates function class that wraps the logic
`shared.ftl`	Terraform	Common infrastructure like IAM roles, logging, etc.

ℹ️ The doc/ folder in the template path is not used during generation. It may contain examples or template prototypes.

🔌 Template Registration

This generator registers itself using:

@TemplateRegistration(
    generatorId = "gcp-terraform",
    templates = {
        @Template(name = "handler", phase = GenerationPhase.SOURCES),
        @Template(name = "function", phase = GenerationPhase.DEPLOYMENT),
        @Template(name = "api", phase = GenerationPhase.DEPLOYMENT),
        @Template(name = "apiIntegration", phase = GenerationPhase.DEPLOYMENT),
        @Template(name = "schedule", phase = GenerationPhase.DEPLOYMENT),
        @Template(name = "shared", phase = GenerationPhase.DEPLOYMENT)
    }
)
public class GcpTerraformJava21TemplateRegistration { ... }

This registration is auto-discovered using Java’s SPI (META-INF/services/...) mechanism.

📂 Output

Artifact	Location
Java handler classes	`target/generated-sources/gcp/`
Terraform configuration	`target/deployment/gcp/*.tf`
Deployment metadata	`target/classes/META-INF/cloudhopper/`
Optional ZIP for deployment	`target/${artifactId}-${version}-gcp.zip`

🧩 What’s Special About GCP

Handler Generation: The generator produces a Java class that implements com.google.cloud.functions.HttpFunction.
Context Mapping: The handler uses GcpCloudFunctionRequestHandler, which adapts GCP’s request/response and environment into Cloudhopper's CloudRequestHandler interface.
Terraform Output: The generated .tf files define the Cloud Function, IAM permissions, and optional API Gateway or scheduler bindings.

Module	Description
`provider-gcp`	Contains `GcpCloudFunctionRequestHandler` used by handlers
`deployment-config-api`	Defines annotations and runtime interfaces

📝 Use this generator to compile and deploy Cloudhopper functions as Google Cloud Functions using Terraform.

📦 How to Use​

1. Add the Maven dependency​

2. Configure the annotation processor​

📁 Templates​

🔌 Template Registration​

📂 Output​

🧩 What’s Special About GCP​

📚 Related Modules​