func OperationHandler()

in operationsbus/handlers.go [334:390]
42 lines of code
8 McCabe index (conditional complexity)

func OperationHandler(matcher *Matcher, hooks []BaseOperationHooksInterface, entityController EntityController) ErrorHandlerFunc {
	return func(ctx context.Context, settler shuttle.MessageSettler, message *azservicebus.ReceivedMessage) error {
		logger := ctxlogger.GetLogger(ctx)

		// 1. Unmarshall the operation
		var body OperationRequest
		err := json.Unmarshal(message.Body, &body)
		if err != nil {
			logger.Error("Error calling unmarshalling message body: " + err.Error())
			return &NonRetryError{Message: "Error unmarshalling message."}
		}

		// 2 Match it with the correct type of operation
		operation, err := matcher.CreateHookedInstace(body.OperationName, hooks)
		if err != nil {
			logger.Error("Operation type doesn't exist in the matcher: " + err.Error())
			return &NonRetryError{Message: "Error creating operation instance."}
		}

		// 3. Init the operation with the information we have.
		_, err = operation.InitOperation(ctx, body)
		if err != nil {
			logger.Error("Something went wrong initializing the operation.")
			return &RetryError{Message: "Error setting operation In Progress"}
		}

		//TODO(mheberling): Remove this after chatting usage is adopted in Guardrails
		var entity Entity
		if entityController != nil {
			entity, err = entityController.GetEntity(ctx, body)
			if err != nil {
				logger.Error("Something went wrong getting the entity.")
				return &RetryError{Message: "Error getting operationEntity"}
			}
		}

		// 4. Guard against concurrency.
		ce := operation.GuardConcurrency(ctx, entity)
		if err != nil {
			logger.Error("Error calling GuardConcurrency: " + ce.Err.Error())
			return &RetryError{Message: "Error guarding operation concurrency."}
		}

		// 5. Call run on the operation
		err = operation.Run(ctx)
		if err != nil {
			logger.Error("Something went wrong running the operation: " + err.Error())
			return &RetryError{Message: "Error running operation."}
		}

		// 6. Finish the message
		settleMessage(ctx, settler, message, nil)

		logger.Info("Operation run successfully!")
		return nil
	}
}