We Keep Coding

How to run python scripts after CMD in Dockerfile?

I have a docker image that exposes 9000 port for server. After the server is running, I need to execute the 3 python scripts which depends on server so, they can only get executed after server.py is running however, after CMD command, the other code do not get executed and remains stuck. What are the possible suggestion to run 3 scripts in same container?
FROM python:3.7.3 as build
WORKDIR /app
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt
COPY . .
# CMD [ "python", "./server.py" ] (The following 3 scripts depends on server.py for execution)
RUN python /app/script1.py
RUN python /app/script2.py
RUN python /app/script3.py
EXPOSE 9000
CMD [ "python", "./server.py" ]

As written in the Dockerfile referece
There can only be one CMD instruction in a Dockerfile
The CMD instruction tells the container what its entry point is, and when running the container, that is what will be run.
If running python ./server.py is a blocking call (which I'm assuming it is, since it's called a server, and most likely responds to some kind of requests), then this won't be possible.
Instead, try restructuring your scripts so that they are run when the server is run, by doing everything you do in script1.py, script2.py, script3.py after the server has been started inside of server.py.
If instead this is about script1.py... sending requests to the server, I'd recommend not including those in the container. Instead, you can simply run those scripts, manually, from the terminal while the server container is running.

You can just execute those scripts from the command line using docker exec after the container has started. You'll just need to know what the container name is
docker exec <CONTAINER NAME> python /app/script1.py
docker exec <CONTAINER NAME> python /app/script2.py
docker exec <CONTAINER NAME> python /app/script3.py
Or just make a bash script, say my_script.sh to run them all and just execute that
#!/usr/bin/env bash
docker exec <CONTAINER NAME> python /app/script1.py
docker exec <CONTAINER NAME> python /app/script2.py
docker exec <CONTAINER NAME> python /app/script3.py
And then
docker exec <CONTAINER NAME> ./my_script.sh

I defined a command in compose.yml like command: "python manage.py runserver 0.0.0.0:8000" it works fine. But when I built t

I defined a command in compose.yml like command: "python manage.py runserver 0.0.0.0:8000" and a port mapping when I try docker-compose up it works fine.
But when I built the image and try to run docker run image it exit immediately.
Only things like docker run -d -p 8000:8000 twitch_test_app python manage.py runserver 0.0.0.0:8000 works even though I already defined the command and the port mapping in docker-compose.yml.
Is there any way to just run ```docker run image without repeating the command that is defined in compose.yml file?
Thanks alot.

I think you are confused between docker-compose and docker.
Think docker-compose as a helper utility that help you easily setup docker environment. When you do docker-compose up, it will create a new image and setup docker container for you with all the configuration that you have specified. Your application will run inside the docker container. Docker-compose just makes life little easier.
However, if you want to just use the docker command you need to specify the same port-mapping and other configurations in the dockerfile itself.
When you do docker run image it will create container for you. But you need to provide entrypoint or command to start your application otherwise it will just exit as docker does not know what to do next. In your case I suppose is a Django project and you need to specify "python manage.py runserver" to start your django server. In dockerfile you can specify it using CMD attribute:
CMD [ "python", "manage.py", "runserver" ]

docker entrypoint behaviour with django

I'm trying to make my first django container with uwsgi. It works as follows:
FROM python:3.5
RUN apt-get update && \
apt-get install -y && \
pip3 install uwsgi
COPY ./projects.thux.it/requirements.txt /opt/app/requirements.txt
RUN pip3 install -r /opt/app/requirements.txt
COPY ./projects.thux.it /opt/app
COPY ./uwsgi.ini /opt/app
COPY ./entrypoint /usr/local/bin/entrypoint
ENV PYTHONPATH=/opt/app:/opt/app/apps
WORKDIR /opt/app
ENTRYPOINT ["entrypoint"]
EXPOSE 8000
#CMD ["--ini", "/opt/app/uwsgi.ini"]
entrypoint here is a script that detects whether to call uwsgi (in case there are no args) or python manage in all other cases.
I'd like to use this container both as an executable (dj migrate, dj shell, ... - dj here is python manage.py the handler for django interaction) and as a long-term container (uwsgi --ini uwsgi.ini). I use docker-compose as follows:
web:
image: thux-projects:3.5
build: .
ports:
- "8001:8000"
volumes:
- ./projects.thux.it/web/settings:/opt/app/web/settings
- ./manage.py:/opt/app/manage.py
- ./uwsgi.ini:/opt/app/uwsgi.ini
- ./logs:/var/log/django
And I manage in fact to serve the project correctly but to interact with django to "check" I need to issue:
docker-compose exec web entrypoint check
while reading the docs I would have imagined I just needed the arguments (without entrypoint)
Command line arguments to docker run will be appended after
all elements in an exec form ENTRYPOINT, and will override all
elements specified using CMD. This allows arguments to be passed to
the entry point, i.e., docker run -d will pass the -d argument
to the entry point.
The working situation with "repeated" entrypoint:
$ docker-compose exec web entrypoint check
System check identified no issues (0 silenced).
The failing one if I avoid 'entrypoint':
$ docker-compose exec web check
OCI runtime exec failed: exec failed: container_linux.go:346: starting container process caused "exec: \"check\": executable file not found in $PATH": unknown

docker exec never uses a container's entrypoint; it just directly runs the command you give it.
When you docker run a container, the entrypoint and command you give to start it are combined to produce a single command line, and that command becomes the main container process. On the other hand, when you docker exec a command in a running container, it's interpreted literally; there aren't two parts of the command line to assemble, and the container's entrypoint isn't considered at all.
For the use case you describe, you don't need an entrypoint script to process the command in an unusual way. You can create a symlink to the manage.py script to give a shorter alias to run it, but make the default command be the uwsgi runner.
RUN chmod +x manage.py
RUN ln -s /opt/app/manage.py /usr/local/bin/dj
CMD ["uwsgi", "--ini", "/opt/app/uwsgi.ini"]
# Runs uwsgi:
docker run -p 8000:8000 myimage
# Manually trigger database migrations:
docker run --rm myimage dj migrate

What should I put for Docker CMD and ENTRYPOINT for Flask app running "python myapp.py images/*"

I am trying to run a Flask app using Docker.
Normally, to execute the Flask app, I run this inside of my Terminal:
python myapp.py images/*
I am unsure of how to convert that to Docker CMD syntax (or if I need to edit ENTRYPOINT).
Here is my docker file:
RUN apt-get update -y
RUN apt-get install -y python-pip python-dev build-essential hdf5-tools
COPY . ~/myapp/
WORKDIR ~/myapp/
RUN pip install -r requirements.txt
ENTRYPOINT ["python"]
CMD ["myapp.py"]
Inside of requirements.txt:
flask
numpy
h5py
tensorflow
keras
When I run the docker image:
person#person:~/Projects/$ docker run -d -p 5001:5000 myapp
19645b69b68284255940467ffe81adf0e32a8027f3a8d882b7c024a10e60de46
docker ps:
Up 24 seconds 0.0.0.0:5001->5000/tcp hardcore_edison
When I got to localhost:5001 I get no response.
Is it an issue with my CMD parameter?
EDIT:
New Dockerfile:
RUN apt-get update -y
RUN apt-get install -y python-pip python-dev build-essential hdf5-tools
COPY . ~/myapp/
WORKDIR ~/myapp/
EXPOSE 5000
RUN pip install -r requirements.txt
CMD ["python myapp.py images/*.jpg "]
With this new configuration, when I run:
docker run -d -p 5001:5000 myapp
I get:
docker: Error response from daemon: OCI runtime create failed: container_linux.go:348: starting container process caused "exec: \"python myapp.py images/*.jpg \": stat python myapp.py images/*.jpg : no such file or directory": unknown.
When I run:
docker run -d -p 5001:5000 myapp python myapp.py images/*.jpg
I get the Docker image to run, but now when I go to localhost:5001, it complains that the connection was reset.

I'm glad you've already solved this issue. I put up this answer just for those who still have the same confusions like you do about ENTRYPOINT and CMD executives.
In a Dockerfile, ENTRYPOINT and CMD are two similar executives, but still have strong difference between them. The most important one(only seems to me) is that CMD could be overwritten but ENTRYPOINT not.
To explain this, I may offer you guys the command blow:
docker run -tid --name=container_name image_name [command]
As we can see, command is optional, and it(if exists) could overwrite CMD defined in Dockerfile.
Let's back to your issue. You may have two ways to achieve your purpose-->
ENTRYPOINT ["python"] and CMD ["/path/to/myapp.py", "/path/to/images/*.jpg"].
CMD python /path/to/myapp.py /path/to/images/*.jpg. This is mentioned by #David Maze above.
To understand the first one, you may take CMD as arguments for ENTRYPOINT.
A simple example below.
Dockerfile-->
FROM ubuntu:18.04
ENTRYPOINT ["cat"]
CMD ["/etc/hosts"]
Build image named test-cmd-show and start a container from it.
docker run test-cmd-show
This would show the content in /etc/hosts file. And go on...
docker run test-cmd-show /etc/resolv.conf
And this would show us the content of /etc/resolv.conf file. And go on ...
docker run test-cmd-show --help
This would show the help information for command cat.
Fantastic, right?
Somehow, we could do more research though this functionality.
Add a relevant question: What's the difference between CMD and ENTRYPOINT?

The important thing is that you need a shell to expand your command line, so I’d write
CMD python myapp.py images/*
When you just write CMD like this (without the not-really-JSON brackets and quotes) Docker will implicitly feed the command line through a shell for you.
(You also might consider changing your application to support taking a directory name as configuration in some form and “baking it in” to your application, if these images will be in a fixed place in the container filesystem.)
I would only set ENTRYPOINT when (a) you are setting it to a wrapper shell script that does some first-time setup and then exec "$#"; or (b) when you have a FROM scratch image with a static binary and you literally cannot do anything with the container besides run the one binary in it.

One issue I found was that the app wasn't accessible to Docker. I added this to app.run:
host='0.0.0.0'
According to this:
Deploying a minimal flask app in docker - server connection issues
Next, Docker panics when you add a directory to the CMD parameters.
So, I removed ENTRYPOINT and CMD and manually added the command to the Docker run:
docker docker run -d -p 5001:5000 myappdocker python myapp.py images/*.jpg

Dockerized web-service does not run in background even with detached flag

I'm trying to Dockerize a web service using Tangelo and python.
My project structure is as follows:
test.py
requirements.txt
Dockerfile
test.py
import ...
def run(query):
...
return response
requirements.txt
... # other packages, numpy, open-cv, etc
tangelo
Dockerfile
FROM ubuntu:latest
RUN apt-get update
RUN apt-get install -y python python-pip git
EXPOSE 9220
ADD . /test
WORKDIR /test
RUN pip install -r requirements.txt
CMD "tangelo --port 9220"
I build this using
docker build -t "test" .
And run in detached mode using
docker run -p 9220:9220 -d "test"
But docker ps shows me that the docker stops almost as soon as it has started. I don't know what the problem is since I cannot inspect the logs.
I have tried a lot of things but I still can't figure this thing out.
Any ideas? If needed, I can provide more info.
EDIT:
When I build, step 8 says
Step 8/8 : ENTRYPOINT tangelo --port 9220
---> Running in 8b54841853ab
Removing intermediate container 8b54841853ab
So it means these are run in an intermediate container. Why is that and how can I prevent it?

TL;DR: Use:
CMD tangelo -np --port 9220
Instead of:
CMD "tangelo --port 9220"
Explanation:
You have two ways to debug the problem:
Inspect the logs of the container:
$ docker run -d test
28684015e519c0c8d644fccf98240d1465acabab6d16c19fd59c5f465b7f18af
$ sudo docker logs 28684015e519c
/bin/sh: 1: tangelo --port 9220: not found
Instead of running in detached mode, run in foreground with -i/--interactive (and optionally also -t/--tty):
$ docker run -ti test
/bin/sh: 1: tangelo --port 9220: not found
As you can see from above, the problem is that tangelo --port 9220 is being interpreted as a single argument. Split it by removing quotes:
CMD tangelo --port 9220 # this will use a shell
or use the "exec" form (preferred, given that you don't need any shell features):
CMD ["tangelo", "--port", "9220"] # this will execute tangelo directly
or even better use ENTRYPOINT + CMD:
ENTRYPOINT ["tangelo"]
CMD ["--port", "9220"] # this will execute tangelo directly
After this change, you'll still have a problem:
$ sudo docker run -ti test
...
[29/Apr/2018:02:43:39] TANGELO no such group 'nobody' to drop privileges to
Tangelo is complaining about the fact that there is no user and group named nobody inside the container. Again, there are two things you can do: add a RUN to create the nobody user and group, or run Tangelo with the -np/--no-drop-privileges option:
ENTRYPOINT ["tangelo"]
CMD ["--no-drop-privileges", "--port", "9220"]
It's fine if during the build you see intermediate containers: Docker creates them for each build step. The commands you specify in ENTRYPOINT or CMD are not executed during build, they're just recorded into the final image.