Sending emails on a schedule with AWS EventBridge, AWS Lambda, AWS SES with offline support using the Serverless framework.
serverless.yml defines a sendEmail AWS Lambda function that is invoked every minute (using EventBridge under the hood). It also states that when it is invoked it should call the main function in handler(.js). There's also some basic IAM statements that grant the function permission to send emails via SES. The handler itself uses the AWS SES V2 SDK to send a fairly basic email when it is invoked.
To get it working locally, we add the serverless-offline and serverless-offline-ses-v2 plugins to serverless.yml. This allows us to simulate the parts of AWS we need locally. When we call npm start, this runs the start script in package.json that starts up the plugins. serverless-offline automatically sets the IS_OFFLINE environment variable so we know to set up the AWS SES V2 SDK to point at serverless-offline-ses-v2.
We can see the results of the function locally by opening up the viewer that aws-ses-v2-local starts up for us (which is managed by the serverless-offline-ses-v2 plugin):
npm install
npm start
Open localhost:8005 to see the emails being sent.
By default, the function will be invoked every minute. If you want to invoke it manually and have the AWS CLI installed, you can open another terminal and run:
aws lambda invoke /dev/null \
--endpoint-url http://localhost:3002 \
--function-name aws-node-ses-send-email-and-offline-dev-sendEmail
More details on manually invoking Lambda functions locally can be found in the serverless-offline documentation.
serverless deploy