AWS - Serverless: <4> Error Handler & Logging

1. Error Handler

• When lambda throw an Exception, it will push into the destination defined in DeadLetterQueue properties.

• Using a lambda function to listen this queue and handle this error.

ErrorDLQueue:
    Type: AWS::SNS::Topic
ConsumeMsgFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: customer
      Handler: com.anhnt.customer.DeliverMsg::onSNSMessage
      DeadLetterQueue:
        Type: SNS
        TargetArn: !Ref ErrorDLQueue

2. Logging

• Go to AWS service 'Cloud watch' to check logs:

• For logging, you have 3 ways to log to 'cloud watch'

  • System.out.println;

  • LambdaLogger logger = context.getLogger();

  • Using Log4j library