Understanding events and AWS Lambda
Lambda works in a very similar way, as explained in the previous section. For instance, the emitters and channels act as the Lambda event source while the functions that we have been creating all this time act as the event consumers.
All in all, when an event is triggered by a particular AWS service, or even from an external source such as an application, that event gets mapped to a particular Lambda function which in turn, executes an action based on the code that you have written for it. This one-to-one mapping of events with their corresponding Lambda functions is what we call as Event Source Mapping and it is responsible for the automatic invocation of your Lambda functions whenever an event is fired.
There are two main categories of event sources supported by Lambda:
- AWS services: Lambda supports a few of AWS's services as preconfigured event sources that you can use to develop easy event-driven systems with. Few of the services namely S3, SNS, SES,...
