serverless-offline-sqs-fix-dlq

serverless-offline-sqs

This Serverless-offline plugin emulates AWS λ and SQS queue on your local machine. To do so, it listens SQS queue and invokes your handlers.

Features:

• Serverless Webpack support.
• SQS configurations: batchsize.

Installation

First, add serverless-offline-sqs to your project:

npm install serverless-offline-sqs

Then inside your project's serverless.yml file, add following entry to the plugins section before serverless-offline (and after serverless-webpack if presents): serverless-offline-sqs.

plugins:
  - serverless-webpack
  - serverless-offline-sqs
  - serverless-offline

See example

How it works?

To be able to emulate AWS SQS queue on local machine there should be some queue system actually running. One of the existing implementations suitable for the task is ElasticMQ.

ElasticMQ is a standalone in-memory queue system, which implements AWS SQS compatible interface. It can be run either stand-alone or inside Docker container. See example sqs service setup.

We also need to setup actual queue in ElasticMQ server, we can use AWS cli tools for that. In example, we spawn-up another container with aws-cli pre-installed and run initialization script, against ElasticMQ server in separate container.

Once ElasticMQ is running and initialized, we can proceed with the configuration of the plugin.

Note that starting from version v3.1 of the plugin, it supports autocreation of SQS fifo queues that are specified in the cloudformation Resources.

Configure

Functions

The configuration of function of the plugin follows the serverless documentation.

functions:
  mySQSHandler:
    handler: handler.compute
    events:
      - sqs: arn:aws:sqs:region:XXXXXX:MyFirstQueue
      - sqs:
          arn: arn:aws:sqs:region:XXXXXX:MySecondQueue
      - sqs:
          queueName: MyThirdQueue
          arn:
            Fn::GetAtt:
              - MyThirdQueue
              - Arn
      - sqs:
          arn:
            Fn::GetAtt:
              - MyFourthQueue
              - Arn
      - sqs:
          arn:
            Fn::GetAtt:
              - MyFifthQueue
              - Arn
resources:
  Resources:
    MyFourthQueue:
      Type: AWS::SQS::Queue
      Properties:
        QueueName: MyFourthQueue
      RedrivePolicy:
        deadLetterTargetArn: # Support only this format for autoCreate
          Fn::GetAtt:
          - MyFourthQueueDlq
          - Arn
        maxReceiveCount: 6

    MyFifthQueue: # Support for Fifo queue creation starts from 3.1 only
      Type: AWS::SQS::Queue
      Properties:
        QueueName: MyFifthQueue.fifo
        FifoQueue: true
        ContentBasedDeduplication: true

    MyFourthQueueDlq:
      Type: AWS::SQS::Queue
      Properties:
        QueueName: MyFourthQueueDlq

SQS

The configuration of aws.SQS's client of the plugin is done by defining a custom: serverless-offline-sqs object in your serverless.yml with your specific configuration.

You could use ElasticMQ with the following configuration:

custom:
  serverless-offline-sqs:
    autoCreate: true                 # create queue if not exists
    apiVersion: '2012-11-05'
    endpoint: http://0.0.0.0:9324
    region: eu-west-1
    accessKeyId: root
    secretAccessKey: root
    skipCacheInvalidation: false