Google Cloud Run deployment cannot find file in ENTRYPOINT

Question

I am following the Google documentation to upload my docker file into the cloud console:

https://cloud.google.com/run/docs/quickstarts/build-and-deploy#python_1

I changed the main.py file to my own app.py which uses Flask. My local Dockerfile is defined as:

# Copyright 2020 Google, LLC.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# [START cloudrun_helloworld_dockerfile]
# [START run_helloworld_dockerfile]

# Use the official lightweight Python image.
# https://hub.docker.com/_/python
FROM python:3.9-slim

# Allow statements and log messages to immediately appear in the Knative logs
ENV PYTHONUNBUFFERED True

# Copy local code to the container image.
ENV APP_HOME /app
WORKDIR $APP_HOME
COPY . ./

# Install production dependencies.
RUN pip install Flask gunicorn

# Run the web service on container startup. Here we use the gunicorn
# webserver, with one worker process and 8 threads.
# For environments with multiple CPU cores, increase the number of workers
# to be equal to the cores available.
CMD exec gunicorn --bind :$PORT --workers 1 --threads 8 --timeout 0 main:app

ENTRYPOINT ["app.py"]

# [END run_helloworld_dockerfile]
# [END cloudrun_helloworld_dockerfile]

I am not sure if ENTRYPOINT is need but without it the service does nothing, complains about not main.py has been found. I can upload the image to the Cloud Run usinggcloud builds submit --tag gcr.io/projectid/webhook , but the deployment will fail both using gcloud console or locally. The error says:

Invalid ENTRYPOINT. [\
name: "gcr.io/projectid/webhook@sha256:706cd97430e6537f91b0ac8c67262ba6a0c10f961c04a4d918ea1649bcead4e3" \
error: "Invalid command \"app.py\": \
file not found anywhere in PATH \"/usr/local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin\"" ].

Why is the file not found? I thought the Dockerfile will instruct to copy everything in the local directory.

Andrew Andrew · Accepted Answer · 2021-01-20T16:02:14

It is helpful to know the difference between the RUN, CMD and ENTRYPOINT commands as they run at different times during the container build.

RUN

The RUN command(s) executes in a new layer and creates a new image, for example, to install software packages. The command runs on top of the current image and creates a new layer by committing the results. Often you will find multiple RUN instructions in a Dockerfile.

CMD

The CMD sets a default command or parameters, which can be overwritten from the command line when docker container runs. If a Docker container has a CMD command, only the last CMD instruction executes and the default ignored.

ENTRYPOINT

The ENTRYPOINT configures a container that will run as an executable. It appears similar to CMD, but the main difference is ENTRYPOINT is NOT ignored when the Docker container runs.

Google Cloud Run deployment cannot find file in ENTRYPOINT

2 Answers