cloudwatch-metrics-aws

Creating Cloudwatch metric alarms

This is a simple example for creating cloudwatch metric alarm. The example creates an alarm based on the metrics of a failing lambda.

In other words: once the lambda fails, the alarm will be triggered - in our example we use SNS notification via email.

Prerequisites

For this example you will need:

• LocalStack Pro, to send emails via SMTP and SES.
• The awslocal command line utility
• A mock SMTP server like smtp4dev or Papercut SMTP to receive the email notifications locally.

To connect LocalStack with the SMTP server, you need to configure the following SMTP environment variables when starting LocalStack:

• SMTP_HOST this should contain the hostname and the port of your mock SMTP server
• SMTP_USER optional, if there is user to connect
• SMTP_PASS optional

For example, when using smtp4dev, simply run:

docker run --rm -it -p 3000:80 -p 2525:25 rnwood/smtp4dev

Navigating to http://localhost:3000 will open a UI to access the email notifications.

Set the environment variable SMTP_HOST=<host-name>:2525 to start LocalStack, where host-name is the name or IP of the host where the SMTP server can be reached.

If you start LocalStack in docker mode, it should be possible to use host.docker.internal. For most operating systems this should resolve the address correctly, e.g.: SMTP_HOST=host.docker.internal:2525.

Alternatively, you can use your real smtp server. Please refer to your provider to set the proper values for SMTP_HOST, SMTP_USER and SMTP_PASS