AWS Credentials needed you need to have AWS credentials to do this (ACCESS_KEY_ID and SECRET_ACCESS_KEY in ~/.aws/credentials)

Full code available on this jupyter notebook

Install boto

$ pip install boto3

Put custom metric

You don't need to create the metric beforehand. The first time you put a value it'll be automatically created for you.

Use this code to send a custom metric to cloudwatch. This will be used as a heartbeat later on.

import boto3

# If you get errors at this point, check your credentials files
# under ~/.aws/credentials
cloudwatch_client = boto3.client('cloudwatch')

cloudwatch_client.put_metric_data(
    MetricData = [
        {
            'MetricName': 'heartbeat',
            'Unit': 'None',
            'Value': 42, # must be a number
            'Dimensions': [
                {
                    'Name': 'feature-name',
                    'Value': 'my-feature-1' 
                }
            ]
        }
    ],
    Namespace='my-app-1'
)

Check metric on Cloudwatch

Make sure you look at the console in the correct region

Once you call the code above at least once, the metric will be available for you to check on the cloudwatch console:

Click on Metrics on the left and select
the metric you have just put and you
will see a point in the graph

Setup alarm

The alarm will be used to check if the heartbeat has not been sent.

In this example, we will get notified if not heartbeat has been sent for 6 hours:

• 1) Click the bell button on the right to setup the alarm

  Click the bell button to open
  the alarm setup screen

• 2) Set condition that will never be met

  As an example, set an alarm that you know will never be triggered.
  We do this because we want to check for missing data instead.

• 3) Open "Additional Configuration" and choose "Treat missing data as bad (breaching threshold)"

  By setting this option, the alarm will go off when
  the metric doesn't get any data,
  which is what we want.

• 4) Click next, choose final details and click "Create Alarm"

  Create alarm, final step

Check alarm condition

Once the alarm is setup, you will be notified if there are no heartbeats sent for 6 hours:

This is what it looks like when there weren't
heartbeats for the last 6 hours