[Python] Passing parameters from AWS EventBridge Pipe to ECS task read by a python application

I am totally at a loss trying to figure out a seemingly simple thing and all searches are taking me in different directions, except offering the clear solution.

I have a python application (not flask/fastapi based) that looks for a command line parameter (an event message from SQS) and process it. I have setup an eventbridge pipe, connected to the SQS queue, which should 'trigger' this Task. So, instead of, say, invoking a lambda function, I am trying to run an ECS task to process this message, on-demand.

However, the issue I am running into is the eventbridge pipe is not passing the message to the application. Here are the relevant portions of the code and configurations:

if __name__ == '__main__':
if len(sys.argv) > 1:
foobar (sys.argv[1])
else:
print("No command line arguments were passed. Nothing to do. Terminating")


The output is always:

No command line arguments were passed. Nothing to do. Terminating
​

Eventbridge pipe is also clearing the message from the queue (so I can't even have my application fetch it from the queue).

Here are the configurations I used. Can someone please guide me on what I seem to be missing? Most answers seem to suggest I need to edit the "Container Override" something I have not been able to find so far either in the task definition or in the eventbridge pipe spec.

Dockerfileredacted)

FROM python:3.13-alpine
...
...
CMD ["python", "app.py"]


Task Definition (redacted as necessary):

{
"taskDefinitionArn": "arn:aws:ecs:us-east-1:999999999999:task-definition/taskdefFooBar:1",
"containerDefinitions": [
{
"name": "taskFooBar",
"image": "999999999999.dkr.ecr.us-east-1.amazonaws.com/foorepo/foobar",
"cpu": 1024,
"memory": 2048,
"memoryReservation": 1024,
"portMappings": [],
"essential": true,
"environment": [],
"environmentFiles": [],
"mountPoints": [],
"volumesFrom": [],
"ulimits": [],
"logConfiguration": {
"logDriver": "awslogs",
"options": {
"awslogs-group": "/loggroupFooBar",
"mode": "non-blocking",
"awslogs-create-group": "true",
"max-buffer-size": "25m",
"awslogs-region": "us-east-1",
"awslogs-stream-prefix": "ecs"
},
"secretOptions": []
},
"systemControls": []
}
],
"family": "taskdefFooBar",
"taskRoleArn": "arn:aws:iam::999999999999:role/roleFoobar",
"executionRoleArn": "arn:aws:iam::999999999999:role/foobarExecutionRole",
"networkMode": "awsvpc",
"revision": 1,
"volumes": [],
"status": "ACTIVE",
"requiresAttributes": [
{
"name": "com.amazonaws.ecs.capability.logging-driver.awslogs"
},
{
"name": "ecs.capability.execution-role-awslogs"
},
{
"name": "com.amazonaws.ecs.capability.ecr-auth"
},
{
"name": "com.amazonaws.ecs.capability.docker-remote-api.1.19"
},
{
"name": "com.amazonaws.ecs.capability.docker-remote-api.1.28"
},
{
"name": "com.amazonaws.ecs.capability.docker-remote-api.1.21"
},
{
"name": "com.amazonaws.ecs.capability.task-iam-role"
},
{
"name": "ecs.capability.execution-role-ecr-pull"
},
{
"name": "com.amazonaws.ecs.capability.docker-remote-api.1.18"
},
{
"name": "ecs.capability.task-eni"
},
{
"name": "com.amazonaws.ecs.capability.docker-remote-api.1.29"
}
],
"placementConstraints": [],
"compatibilities": [
"EC2",
"FARGATE"
],
"requiresCompatibilities": [
"FARGATE"
],
"cpu": "1024",
"memory": "2048",
"runtimePlatform": {
"cpuArchitecture": "X86_64",
"operatingSystemFamily": "LINUX"
},
"registeredAt": "2025-03-23T03:55:41.028Z",
"registeredBy": "arn:aws:iam::999999999999:user/userme",
"enableFaultInjection": false,
"tags": []
}


Event Bridge Configuration:

{
"AWSTemplateFormatVersion": "2010-09-09",
"Description": "CloudFormation template for EventBridge PipeFooBar",
"Resources": {
"Pipexxxxxxxx": {
"Type": "AWS:ipes:ipe",
"DependsOn": [],
"Properties": {
"RoleArn": "arn:aws:iam::999999999999:role/service-role/Amazon_EventBridge_Pipe_FooBar_5aaaa999",
"Name": "ebFooBar",
"Description": "Used to invoke ECS task when there is a new message in SQS",
"DesiredState": "RUNNING",
"Source": {
"Fn::Sub": "arn:${AWS:artition}:sqs:${AWS::Region}:${AWS::AccountId}:queueFoo"
},
"SourceParameters": {
"SqsQueueParameters": {
"BatchSize": 1
}
},
"LogConfiguration": {
"CloudwatchLogsLogDestination": {
"LogGroupArn": {
"Fn::Sub": "arn:${AWS:artition}:logs:${AWS::Region}:${AWS::AccountId}:log-group:/logFoobars"
}
},
"Level": "INFO"
},
"TargetParameters": {
"InputTemplate": "'<$.body>'",
"EcsTaskParameters": {
"TaskDefinitionArn": "arn:aws:ecs:us-east-1:999999999999:task-definition/taskdefFooBar",
"TaskCount": 1,
"LaunchType": "FARGATE",
"NetworkConfiguration": {
"awsvpcConfiguration": {
"Subnets": ["subnet-xxxxxxxxxxxxxxxxx"],
"SecurityGroups": ["sg-yyyyyyyyyyyyyyyyy"],
"AssignPublicIp": "ENABLED"
}
},
"EnableECSManagedTags": true,
"EnableExecuteCommand": false
}
},
"Target": {
"Fn::Sub": "arn:${AWS:artition}:ecs:${AWS::Region}:${AWS::AccountId}:cluster/clstrFooBar"
}
}
}
},
"Parameters": {}
}


Update: I've looked to see if the environment variables has the event message, but no luck.

Continue reading...