How to get the event content in ECS when it is invoked by cloudwatch/eventbridge event?

问题

We can set up event rules to trigger an ECS task, but I don't see if the triggering event is passed to the runing ECS task and in the task how to fetch the content of this event. If a Lambda is triggered, we can get it from the event variable, for example, in Python:

def lambda_handler(event, context):
...

But in ECS I don't see how I can do things similar. Going to the cloudtrail log bucket doesn't sound to be a good way because it has around 5 mins delay for the new log/event to show up, which requires ECS to be waiting and additional logic to talk to S3 and find & read the log. And when the triggering events are frequent, this sounds hard to handle.

回答1:

One way to handle this is to set two targets In the Cloud watch rule.

One target will launch the ECS task
One target will push same event to SQS

So the SQS will contain info like

{
  "version": "0",
  "id": "89d1a02d-5ec7-412e-82f5-13505f849b41",
  "detail-type": "Scheduled Event",
  "source": "aws.events",
  "account": "123456789012",
  "time": "2016-12-30T18:44:49Z",
  "region": "us-east-1",
  "resources": [
    "arn:aws:events:us-east-1:123456789012:rule/SampleRule"
  ],
  "detail": {}
}

So when the ECS TASK up, it will be able to read event from the SQS.

For example in Docker entrypoint

#!/bin/sh
echo "Starting container"
echo "Process SQS event"
node process_schdule_event.sj


#or if you need process at run time
schdule_event=$(aws sqs receive-message --queue-url https://sqs.us-west-2.amazonaws.com/123456789/demo --attribute-names All --message-attribute-names All --max-number-of-messages 1)
echo "Schdule Event: ${schdule_event}"


# one process done, start the main process of the container
exec "$@"

回答2:

After further investigation, I finally worked out another solution that is to use S3 to invoke Lambda and then in that Lambda I use ECS SDK (boto3, I use Python) to run my ECS task. By this way I can easily pass the event content to ECS and it is nearly real-time.

But I still give credit to @Adiii because his solution also works.

来源：https://stackoverflow.com/questions/62807320/how-to-get-the-event-content-in-ecs-when-it-is-invoked-by-cloudwatch-eventbridge

标签

amazon-web-services

amazon-ecs

amazon-cloudwatch