Synchronous & Asynchronous Lambda

• Several AWS services, such as S3 and SNS, invoke functions asynchronously to process events.

• When you invoke a function asynchronously, you don't wait for a response from the function code.

• You hand off the event to Lambda and Lambda handles the rest.

• You can configure how Lambda handles errors, and can send invocation records to a downstream resource to chain together components of your application.

• Lambda supports the synchronous and asynchronous invocation of a Lambda function.

• You can control the invocation type only when you invoke a Lambda function.

• When you use an AWS service as a trigger, the invocation type is predetermined for each service.

• You have no control over the invocation type that these event sources use when they invoke your Lambda function.

• For short-term, Lambda is a very cost-effective choice.

• You can use a Lambda function to process messages in an SQS queue.

  • Lambda event source mappings support standard queues and FIFO queues.

• With SQS, you can offload tasks from one component of your application by sending them to a queue and processing them asynchronously.

• Kinesis Data Streams is a real-time data streaming service that requires the provisioning of shards.

  • With SQS only pay for what you use, so it is a cheaper alternative.

• If you don't need real-time processing, replacing Kinesis Data Streams with SQS would lower costs.