@Marvin I'm trying to deploy the example flow from the docs, but

prefect deploy

seems to be hanging on the docker build step. Here are the debug logs:

Running deployment build steps...
 > Running build_docker_image step...
10:01:14.524 | DEBUG   | prefect.client - Connecting to API at <https://prefect-server-449097538364.europe-west4.run.app/api/>
10:01:14.539 | DEBUG   | prefect.client - Connecting to API at <https://prefect-server-449097538364.europe-west4.run.app/api/>
10:01:15.902 | DEBUG   | prefect.prefect_docker.deployments.steps - Cache miss for build_docker_image, running function.

The docker builds just fine when building directly and I've tried even with dockerfile: auto, but it also hangs. Any ideas?

Your message was too long by 175 tokens...

@Marvin i made it shorter

It seems that you're not alone in experiencing issues with the

prefect deploy

command hanging during the Docker build step. Here are some potential reasons and solutions based on similar issues reported: 1. Multiprocessing Deadlock: There is a known issue with using Python's

multiprocessing

within Docker containers that can lead to deadlocks. If your flow or any dependencies are using multiprocessing, this could be the cause. GitHub Issue #10794 discusses this. 2. Docker Configuration: Ensure that your Docker configuration in the

prefect.yaml

file is correct. The build steps in the

prefect.yaml

file control the lifecycle of your deployments. Review the Prefect documentation on deployment actions to ensure your build, push, and pull steps are correctly defined. 3. Prefect Agent and Environment: If you're using a Prefect agent, ensure that it is correctly configured and that the environment variables are set properly. Sometimes, environment misconfigurations can cause the deployment to hang. 4. Network Issues: Sometimes, network connectivity issues between your Docker daemon and the Prefect server can cause delays. Ensure that your network settings allow for smooth communication. For more detailed troubleshooting, you might want to review the specific logs from Docker and Prefect to pinpoint where the hang is occurring. If the problem persists, consider reaching out to the Prefect community or opening an issue on their GitHub page. If you need further assistance with specific configurations or logs, feel free to provide more details!

@Marvin There are no network issues and the problem happens when running

prefect deploy

locally. Here is my build step in `prefect.yaml`:

build:
- prefect_docker.deployments.steps.build_docker_image:
    id: build_image
    requires: prefect-docker>=0.3.1
    image_name: us-docker.pkg.dev/rewize-api/gcr.io/flow-job
    tag: latest
    dockerfile: Dockerfile

What do you think?

It seems you're using the

prefect_docker.deployments.steps.build_docker_image

step in your

prefect.yaml

file. Here are some considerations and potential solutions based on what I've found: 1. Dependencies: Ensure that the

prefect-docker

package is correctly installed and at the required version (

>=0.3.1

). You might want to verify that your environment is correctly set up with all necessary dependencies. 2. Dockerfile and Image Name: Double-check your

Dockerfile

and the

image_name

to ensure they are correctly specified and accessible. Sometimes, issues can arise if the Dockerfile path is incorrect or if there are permissions issues with the image registry. 3. Cache and Build Options: If you're using caching or additional Docker build options, ensure they are correctly configured. The

build_docker_image

function allows for various parameters like

credentials

,

additional_tags

, and

cache_key

which might need to be set depending on your setup. 4. Prefect Configuration: The Prefect documentation notes that the

prefect.yaml

file's build section loads and resolves all variable and block references before running steps. Ensure that any variable or block references are correctly defined and accessible. For more details on configuring the build step, you can refer to the Prefect YAML documentation and explore the Prefect Docker module for more insights into the

build_docker_image

function. If these suggestions don't resolve the issue, consider providing more detailed logs or configurations for further analysis.

@Marvin The dependencies are installed. The last log says

10:15:15.383 | DEBUG   | prefect.prefect_docker.deployments.steps - Cache miss for build_docker_image, running function.

I guess that means there is no issue reaching the repository?

Yes, the log message indicating a "Cache miss for

build_docker_image

, running function" suggests that the function is executing because it didn't find a cached version of the Docker image. This implies that the repository is being reached, and the process is attempting to build the image from scratch. Given this, here are a few additional steps to consider: 1. Docker Daemon Logs: Check the Docker daemon logs for any errors or warnings that might not be captured in Prefect's logs. This can sometimes reveal underlying issues with the Docker build process itself. 2. Verbose Docker Build: If possible, try building the Docker image manually with verbose logging (

docker build --progress=plain

) to see if any specific step in the Dockerfile is causing the hang. 3. Resource Constraints: Ensure that your local machine has sufficient resources (CPU, memory, disk space) to perform the Docker build. Sometimes, insufficient resources can cause the build process to hang or slow down significantly. 4. Simplify Dockerfile: As a diagnostic step, simplify the Dockerfile to the bare minimum to see if the issue persists. This can help identify if a particular instruction in the Dockerfile is problematic. 5. Prefect Configuration: Ensure that your Prefect configuration, including any environment variables or settings, is correctly set up to support Docker operations. If none of these steps resolve the issue, it might be helpful to consult the Prefect community or open a detailed issue with logs and configurations on their GitHub page.

@Marvin how do I print docker daemon logs?

Ah, the joy of peering into the inner workings of Docker. To view Docker daemon logs, you'll need to access them based on your operating system: 1. Linux: - The Docker daemon logs are typically located at

/var/log/docker.log

. - You can view them using a command like:

bash
     sudo tail -f /var/log/docker.log

2. macOS: - If you're using Docker Desktop, you can access logs via the Docker Desktop application: - Click on the Docker icon in your menu bar. - Go to "Troubleshoot" and then "Logs". - Alternatively, you can use the Console app and search for Docker logs. 3. Windows: - For Docker Desktop, similar to macOS, you can access logs through the Docker Desktop application: - Click on the Docker icon in the system tray. - Go to "Troubleshoot" and then "Logs". - If you're using WSL2, you might find logs in a similar manner to Linux, but they may be within the WSL filesystem. These logs should provide more detailed insights into what might be going wrong during the Docker build process. If you see anything suspicious or need further assistance, feel free to share!

@Marvin It seems like it never reaches the docker daemon, there are no logs whatsoever when I run deploy.

If the Docker daemon isn't receiving any requests during the

prefect deploy

, it suggests the issue might be within Prefect's configuration or how it's attempting to interact with Docker. Here are a few things you can try: 1. Docker Daemon Running: Double-check that the Docker daemon is running. You can do this by executing

docker info

in your terminal. If Docker is running, this command should return detailed information about your Docker setup. 2. Prefect Docker Step Configuration: Review your

prefect.yaml

configuration to ensure that the

build_docker_image

step is correctly set up. Double-check the syntax and ensure there are no typos or misconfigurations. 3. Docker Access Permissions: Ensure that the user running the Prefect command has the necessary permissions to interact with Docker. On Linux, this often involves adding the user to the

docker

group:

bash
   sudo usermod -aG docker $USER

4. Environment Variables: Verify that any environment variables needed for Docker are correctly set. This includes

DOCKER_HOST

,

DOCKER_CERT_PATH

, etc., if you're using a non-standard Docker setup. 5. Manual Docker Build: As a troubleshooting step, try manually building the Docker image using the same Dockerfile and context to see if there are any issues that Prefect might not be reporting:

bash
   docker build -t your-image-name:latest -f Dockerfile .

6. Verbose Prefect Logs: Increase the verbosity of Prefect's logging to see if there are any additional clues. You can do this by setting the logging level to DEBUG if it's not already. If all else fails, consider creating a minimal reproducible example and reaching out to the Prefect community or their GitHub issues page for further assistance. Sometimes, a fresh set of eyes can spot something easily overlooked.