Hi gang I am playing around with getting data logged to the Prefect Community #ask-community

Hi gang, I am playing around with getting data log...

Eddie Atkinson

08/19/2021, 2:32 AM

Hi gang, I am playing around with getting data logged to the stdout to be displayed in both the prefect logs and my team’s cloudwatch logs. Does anyone have any ideas how to do this? The flow is super simple but the logs aren’t showing up in cloudwatch:

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from prefect.run_configs import ECSRun
from prefect import task, Flow
from prefect.storage import S3
import prefect

TASK_ARN = "an arn"
STORAGE = S3(bucket="my-cool-bucket")
LABELS = ["a label"]

RUN_CONFIG = ECSRun(
    labels=LABELS,
    task_role_arn=TASK_ARN,
    image="prefecthq/prefect:latest-python3.8",
    memory=512,
    cpu=256,
)


@task(log_stdout=True)
def bye_world():
    print("bye world")


@task(log_stdout=True)
def hello_world():
    print("Hello, World!")


with Flow("test_flow", run_config=RUN_CONFIG, storage=STORAGE) as flow:
    hello_world()
    bye_world()


flow.register(project_name="Tesla")

Eddie Atkinson

08/19/2021, 2:32 AM

My hunch is that I need to get a log group attached to my task definition. However, it looks like prefect creates a new task definition on each run, so I guess I need to specify the details of that?

Eddie Atkinson

08/19/2021, 4:53 AM

Never mind, I figured it out. For anyone who is interested I created another ECS task, attached a log group, and then specified the task definition family as the

task_definition_arn

in the call to

ECSRun

. I’m using the serverless framework and here is the config for those that are interested:

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tasks:
      prefect-task:
        name: ${self:custom.ecsTaskName}-prefect-task
        image: 'prefecthq/prefect:latest-python3.8'
        desired: 0
        cpu: 256 # 0.25vcpu
        memory: 512 # 512mb
        override:
          role: ${self:custom.ecsBaseTaskRoleName}
          container: 
            Name: flow 
            # container must be called 'flow' for prefect to run tasks 
            # when using ECSRun: <https://docs.prefect.io/api/latest/run_configs.html#ecsrun>
            LogConfiguration:
              LogDriver: "awslogs"
              Options:
                awslogs-group: ${self:custom.ecsClusterLogGroupName}
                awslogs-region: ${self:custom.region}
                awslogs-stream-prefix: ${self:custom.ecsTaskLogPrefix}

With this flow:

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RUN_CONFIG = ECSRun(
    labels=LABELS,
    task_definition_arn=TASK_DEFINITION_FAMILY,
    memory=512,
    cpu=256,
)


@task(log_stdout=True)
def bye_world():
    print("bye world")


@task(log_stdout=True)
def hello_world():
    print("Hello, World!")


with Flow("a_flow", run_config=RUN_CONFIG, storage=STORAGE) as flow:
    hello_world()
    bye_world()

Kevin Kho

08/19/2021, 4:54 AM

@Marvin archive “Log ECS Task to CloudWatch”

Marvin

08/19/2021, 4:54 AM

https://github.com/PrefectHQ/prefect/issues/4883

Kevin Kho

08/19/2021, 4:55 AM

Hey @Eddie Atkinson, thanks for circling back. I was gonna suggest doing it on the agent side like this , but I think the run config is better.

Eddie Atkinson

08/19/2021, 5:02 AM

Hi @Kevin Kho, thanks for your reply. I think my approach works best for my use case as members of my team can now define arbitrary flows to run with that task definition and always know that they’re going to get logs on Cloudwatch without needing to fiddle with task definitions themselves. P.S. I think it’s great that Prefect is open source, being able to read through source code is sometimes a great complement to the documentation!

Kevin Kho

08/19/2021, 5:03 AM

I agree with the approach 👍 And yes, the codebase is pretty legible so we have a lot of users subclassing things

👍 1

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