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README.md

Simple Lambda Complex Example

This is a very simple example Lambda Complex application that reads input data from a queue, transforms it, and takes action on it at a set concurrency. The components created on deployment are:

  • simple-<deployId>-MessageTransformerQueue SQS queue.
  • simple-<deployId>-MessageProcessorQueue SQS queue.
  • simple-<deployId>-MessageTransformerConcurrencyQueue SQS queue.
  • simple-<deployId>-MessageProcessorConcurrencyQueue SQS queue.
  • simple-<deployId>-LambdaComplexCoordinatorConcurrencyQueue SQS queue.
  • simple-<deployId>-LambdaComplexInvokerConcurrencyQueue SQS queue.
  • simple-<deployId>-MessageTransformer-<assignedId> Lambda function.
  • simple-<deployId>-MessageProcessor-<assignedId> Lambda function.
  • simple-<deployId>-InvokedProcessor-<assignedId> Lambda function.
  • simple-<deployId>-LambdaComplexCoordinator-<assignedId> Lambda function.
  • simple-<deployId>-LambdaComplexInvoker-<assignedId> Lambda function.

How the Application Functions

The simple-<deployId>-LambdaComplexCoordinator-<assignedId> Lambda function constantly invokes itself to monitors queues and invoke other Lambda functions in response to the presence of queue messages. The entry point for data into the application is the simple-<deployId>-MessageTransformerQueue queue. Messages added there will cause the coordinator to invoke the simple-<deployId>-MessageTransformer-<assignedId> Lambda function once per message.

The simple-<deployId>-MessageTransformer-<assignedId> Lambda function consumes a message from the simple-<deployId>-MessageTransformerQueue queue, alters the message contents, and then passes that data on to either the simple-<deployId>-MessageProcessor-<assignedId> function or the simple-<deployId>-InvokedProcessor-<assignedId> Lambda function depending on the length of the contents.

If sending the data to the simple-<deployId>-MessageProcessor-<assignedId> function it adds a message containing the data to the simple-<deployId>-MessageProcessorQueue queue.

If sending the data to the simple-<deployId>-InvokedProcessor-<assignedId> function, then it invokes that function directly.

Both of the processor Lambda functions use the same underlying NPM package and function. The only difference is how they are invoked, either directly or in response to a queue message.

The processor function simply logs the message it receives and then exits.

Illustrating the Basics

Obviously this is trivial and contrived, but serves to show off the basics:

  • Lambda Complex application configuration and deployment.
  • Lambda functions reading from queues.
  • Lambda function A passing data to Lambda function B via a queue.
  • Lambda function A directly invoking Lambda function B to pass data.

A real Lambda Complex application will use these same building blocks, but to a more constructive end.

Configuring the Application

Update examples/simple/applicationConfig.js to set the following properties to match the AWS account to deploy into:

  • region
  • s3Bucket
  • s3KeyPrefix

Launching the Application

After configuring examples/simple/applicationConfig.js, run the following:

grunt lambda-complex-deploy --config-path=examples/simple/applicationConfig.js

Setting the Application in Motion

Once deployment is complete, add messages containing any valid JSON string to the simple-<deployId>-MessageTransformer-<assignedId> queue to see the Lambda functions triggered in response.