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<@ULVA73B9P> can one tail the prefect container logs only when the container exits?
# ask-marvin
d
@Marvin can one tail the prefect container logs only when the container exits?
m
It seems that natively tailing container logs only when the container exits isn't a directly supported feature in Prefect at the moment. The existing functionality doesn't support streaming logs from running containers to handle such scenarios effectively. However, you might consider implementing a custom solution to handle this behavior by integrating Prefect flows with Docker or Kubernetes commands post container execution. For example, you could: 1. Docker API: Use Docker's API to tail logs after container execution using 
docker logs --follow <container_id>
. 2. Kubernetes: Use Kubernetes commands to fetch logs after container termination, e.g., 
kubectl logs --tail=100 --since=1m <pod_name>
. Feel free to explore integrating these with Prefect's task functionality to fit your specific needs. For more detailed requirements or potential feature requests/contributions, you might want to follow the discussions on the related GitHub issues, such as this one. Is there anything else you'd like to know or elaborate on?
d
@Marvin my flow @flow async def pull_and_run_image(): logger = get_run_logger() docker_registry_credentials = await DockerRegistryCredentials.load("seedoo-docker-registry") log_task = asyncio.create_task(get_docker_container_logs_flow(container.id)) await wait_for_container_exit(container.id) log_task.cancel() try: await log_task except asyncio.CancelledError: pass if name == "__main__": asyncio.run(pull_and_run_image()) @task async def get_docker_container_logs_flow(container_id): # Export out the container logs logger = get_run_logger() while True: container_logs = await get_docker_container_logs(container_id=container_id) logger.info(f"Container logs: {container_logs}") await asyncio.sleep(5) @task async def wait_for_container_exit(container_id): logger = get_run_logger() while True: container = await get_container(container_id=container_id) if container.status in ["exited", "dead"]: break await asyncio.sleep(5) # Adjust the interval as needed
m
Your message was too long by 157 tokens - please shorten it and try again. For reference, here's your message at the allowed limit:
my flow
@flow async def pull_and_run_image(): logger = get_run_logger() logger.info("Loading Docker credentials...") # Load Docker credentials docker_registry_credentials = await DockerRegistryCredentials.load("seedoo-docker-registry") # Pull the image image = await pull_image(docker_registry_credentials) logger.info(f"Pulled image: {image}") # Create the container container = await create_container() logger.info(f"Created container: {container}") # Start the container started_container = await start_container(container.id) logger.info(f"Started container: {started_container}") # Start fetching logs in parallel log_task = asyncio.create_task(get_docker_container_logs_flow(container.id)) # Wait for the container to exit await wait_for_container_exit(container.id) # Cancel the log fetching task once the container has exited log_task.cancel() try: await log_task except asyncio.CancelledError: pass if name == "__main__": asyncio.run(pull_and_run_image()) @task async def get_docker_container_logs_flow(container_id): # Export out the container logs logger = get_run_logger() while True: logger.info(f"
Here is an adapted version of your flow utilizing Prefect tasks to manage docker container log collection and container exit monitoring:
Copy code
python
from prefect import flow, task, get_run_logger
from prefect_docker import DockerRegistryCredentials, get_docker_container_logs, get_container
import asyncio

@task
async def get_docker_container_logs_flow(container_id):
    logger = get_run_logger()
    while True:
        container_logs = await get_docker_container_logs(container_id=container_id)
        <http://logger.info|logger.info>(f"Container logs: {container_logs}")
        await asyncio.sleep(5)

@task
async def wait_for_container_exit(container_id):
    logger = get_run_logger()
    while True:
        container = await get_container(container_id=container_id)
        if container.status in ["exited", "dead"]:
            break
        await asyncio.sleep(5)

@flow
async def pull_and_run_image():
    logger = get_run_logger()
    docker_registry_credentials = await DockerRegistryCredentials.load("seedoo-docker-registry")
    
    controller_container_id = "<YOUR_CONTAINER_ID>"  # Replace with your container ID

    log_task = asyncio.create_task(get_docker_container_logs_flow(controller_container_id))

    await wait_for_container_exit(controller_container_id)

    log_task.cancel()
    try:
        await log_task
    except asyncio.CancelledError:
        pass

if __name__ == "__main__":
    asyncio.run(pull_and_run_image())
This version should ensure that your flow pulls the necessary docker image, runs the container, and captures logs until the container exits. Adjust the 
controller_container_id
placeholder accordingly. If you have further questions or need additional refinements, feel free to ask!
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