Error in Prefect when build docker image, what triggers Prefect to create the tmp folder with healthcheck.py

Question

When using docker as storage, in the call as below:

prefect register --project yourproject -p yourflow.py

It seems that perfect creates a tmp{randomNumber} folder and puts healthcheck.py and a Dockerfile, which participate the docker build.

But I accidentally deleted the tmp folder, even after I recovered it, it still throws the following error. What happened was that Prefect expected a tmp folder with a new random_number as the suffix. How can I recover from it?

Step 10/11 : COPY ./tmpnu2k398p/healthcheck.py /opt/prefect/healthcheck.py
COPY failed: stat /var/lib/docker/tmp/docker-builder531146691/tmpnu2k398p/healthcheck.py: no such file or directory
Error loading 'prefect_register_flow.py':
  Traceback (most recent call last):
    File "/Users/zhengxie1/workspace/cog_ana_model_train/venv/lib/python3.7/site-packages/prefect/cli/build_register.py", line 134, in load_flows_from_script
    namespace = runpy.run_path(abs_path, run_name="<flow>")
    File "/Users/zhengxie1/.pyenv/versions/3.7.3/lib/python3.7/runpy.py", line 263, in run_path
    pkg_name=pkg_name, script_name=fname)
    File "/Users/zhengxie1/.pyenv/versions/3.7.3/lib/python3.7/runpy.py", line 96, in _run_module_code
    mod_name, mod_spec, pkg_name, script_name)
    File "/Users/zhengxie1/.pyenv/versions/3.7.3/lib/python3.7/runpy.py", line 85, in _run_code
    exec(code, run_globals)
    File "/Users/zhengxie1/workspace/cog_ana_model_train/prefect_register_flow.py", line 77, in <module>
    flow.storage.build()
    File "/Users/zhengxie1/workspace/cog_ana_model_train/venv/lib/python3.7/site-packages/prefect/storage/docker.py", line 303, in build
    self._build_image(push=push)
    File "/Users/zhengxie1/workspace/cog_ana_model_train/venv/lib/python3.7/site-packages/prefect/storage/docker.py", line 370, in _build_image
    "Your docker image failed to build!  Your flow might have "
  ValueError: Your docker image failed to build!  Your flow might have failed one of its deployment health checks - please ensure that all necessary files and dependencies have been included.

score 1 · Answer 1 · answered Dec 02 '21 at 11:09

As a quick fix, you could disable the health check:

from prefect.storage import Docker

Docker(ignore_healthchecks=True)

In general, it looks like you run the registration itself in a Docker container, and this is why the health checks are failing. The registration step is building an image and right now you are building Docker images from a Docker container rather than from a local process. You could in theory solve it with docker.sock, but there is a much easier way.

You can create a virtual environment for the registration process. Within that environment, you can register all flows at once using CLI rather than doing that with a custom code:

prefect register --project yourproject -p /path/to/flows/dir/

All flows in the dir directory, will then be registered one by one, and for each of them, Prefect will build its own Docker image.

Error in Prefect when build docker image, what triggers Prefect to create the tmp folder with healthcheck.py

1 Answers1