Adding a Functional Endpoint

Workflow

Copy this checklist and track your progress:

Creating or modifying a functional endpoint:
- [ ] Step 1: Read local AGENTS.md file
- [ ] Step 2: Define in service.yaml
- [ ] Step 3: Generate Boilerplate Code
- [ ] Step 4: Define Custom Types
- [ ] Step 5: Move Implementation and Test if Renamed
- [ ] Step 6: Implement the Business Logic
- [ ] Step 7: Test the Function
- [ ] Step 8: Document the Microservice
- [ ] Step 9: Versioning

Step 1: Read local AGENTS.md file

Check for and read a local AGENTS.md file in that microservice's directory. The local AGENTS.md file contains microservice-specific instructions that should take precedence over global instructions.

Step 2: Define in service.yaml

Define the functional endpoint in the functions array in the service.yaml of the microservice.

• The signature of the functional endpoint must follow Go function syntax exactly. Do not include a context.Context input argument nor an error output argument.
• The description should explain what the function is doing. It should start with the name of the function.
• A method restricts requests to a specific HTTP method such as GET, POST, DELETE, PUT, PATCH, OPTIONS or HEAD. The default ANY accepts all requests regardless of the method.

functions:
  - signature: MyNewFunction(primitiveParam string, customParam CustomType) (result string)
    description: MyNewFunction does X, Y and Z.
	method: ANY

Step 3: Generate Boilerplate Code

If you've made changes to service.yaml, run go generate to generate the boilerplate code.

Step 4: Define Custom Types

If the new function is using non-primitive custom types such as structs, look for their definition in the API directory.

• Define the properties of any custom types as needed. Property names should be in PascalCase.
• Define JSON tags for all properties. JSON tag names should be in camelCase. Include ,omitzero in all JSON tags.

// CustomType is X, Y, Z
type CustomType struct {
	PropertyName string `json:"propertyName,omitzero"`
}

Step 5: Move Implementation and Test if Renamed

If you made a change to the name of the method in the signature field, you need to move over its implementation in service.go from under the old name to the new name. Similarly, you'll need to move over the implementation of the tests in service_test.go.

Step 6: Implement the Business Logic

Look for the function declaration in service.go and implement or adjust its logic appropriately.

func (svc *Service) MyNewFunction(ctx context.Context, primitiveParam string, customParam CustomType) (result string, err error) {
	// Implement logic here
	return result, err
}

Step 7: Test the Function

Look for the integration test created in service_test.go for the function and implement or adjust it appropriately.

• Follow the pattern recommendation in the code
• Add downstream microservices or their mocks to the testing app

func TestMyservice_MyNewFunction(t *testing.T) {
	// Implement testing here
}

Step 8: Document the Microservice

Generate documentation for this microservice that captures its purpose, context, and design rationale. Focus on the reasons behind decisions rather than describing what the code does. Explain design choices, tradeoffs, and the context needed for someone to safely evolve this microservice in the future. Store the result in the microservice's local AGENTS.md file.

Step 9: Versioning

Run go generate to version the code.