LambdaWorker Example: SimpleLambdaWorker

This is an example of using the LambdaWorker in a simple worker.

The LambdaWorker:

is subscribed to an SQS queue whose trigger is enabled by default
sends failed jobs to another SQS queue - a dead letter queue
is subscribed to the dead letter queue but this trigger is disabled by default
allows for the replay of failed jobs with the talis-cli tools awsdlq tool
triggers an alarm for failed jobs
triggers an alarm when the queue of jobs exceeds a configuarble maximum threshold
triggers an alarm when a message waiting on the queue is older than a configurable maximum

Optionionally, the LambdaWorker:

can have its SQS queue subscribed to an SNS topic.
- For example all Depot workers subscribe to a "File" topic in a Pub/Sub architecture.
can have a filterPolicy specified so that it only receives messages from the SNS topic which it is interested in.

Construct Diagram

Note:

The talis-cli-tools awsdlq tool can be used to replay messages. See the tech team talk on the awsdlq here.

This Example

To build and deploy this example:

export AWS_PREFIX=development-XX- where XX are your initials
- This is used in the name of the stack and resources created, so that they do not clash with anyone elses stack in AWS
source awsenv <profile> to set your credentials to the shared account
npm install
npm run build
cdk deploy

After you have finished with the example, remove your stack in AWS using:

cdk destroy

Useful commands

npm run build compile typescript to js
npm run watch watch for changes and compile
npm run test perform the jest unit tests
cdk deploy deploy this stack to your default AWS account/region
cdk diff compare deployed stack with current state
cdk synth emits the synthesized CloudFormation template