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Running pytest command outside of docker container failes because container stopped

I use docker selenium grid and pytest to execute tests. What i now do is:
Spin up selenium grid via a makerfile
Spin up the docker container (with a volume pointing to my local pc for the tests). The container also runs the pytest command.
This all works good, except that i would rather split the second action and be able to run the test on an already running container. Preferred setup:
Spin up selenium grid + docker container with pyton+pytest
A command to run the tests (with the container as interpretor)
When i tried to do this, i faced the issue that the python+pytest container stops running when the commands are all done. There is no long living process.
Dockerfile
FROM python:3.9.0-alpine
RUN apk add tk
COPY requirements.txt requirements.txt
RUN pip install -r requirements.txt
RUN ls ..
CMD pytest --junitxml ../r/latest.xml
My docker-compose file looks like:
docker-compose.yml
version: "3.0"
services:
pytest:
container_name: pytest
build:
context: .
dockerfile: Dockerfile
volumes:
- ./t:/t
- ./r:/r
working_dir: /t/
networks:
default:
name: my_local_network #same as selenium grid
It does not 'feel' good to have this pytest command in the container settings itself.

Container shutting down
That's because the CMD pytest --junitxml ../r/latest.xml line will execute once and when complete it will exit the container.
To run a cmd on an existing container
You can run commands on an existing docker container using this command:
docker exec <container_name> python -m pytest
Where <container_name> would be pytest in your case, since that is what the container is called in your docker-compose.yml file.
See here for more info: https://docs.docker.com/engine/reference/commandline/exec/
Using Make
If you want to extend this to a makefile command:
docker:
docker-compose up -d
ci-tests: docker
docker exec <container_name> python -m pytest
To both spin up AND run tests you can use:
make ci-tests
You could run selenium-grid in docker too if you wanted to make this solution completely portable: https://www.conductor.com/nightlight/running-selenium-grid-using-docker-compose/

View Docker Swarm CMD Line Output

I am trying to incorporate a python container and a dynamodb container into one stack file to experiment with Docker swarm. I have done tutorials on docker swarm seeing web apps running across multiple nodes before but never built anything independently. I am able to run docker-compose up with no issues, but struggling with swarm.
My docker-compose.yml looks like
version: '3.3'
services:
dynamodb:
image: "amazon/dynamodb-local"
ports:
- "8000:8000"
track-count:
image: "my-app"
links:
- "dynamodb:localhost"
Running docker stack deploy -c docker-compose.yml trial_stack brings up no errors however printing 'hello world' as the first line of python code is not displayed in the terminal. I get the following as CMD line output
Ignoring unsupported options: links
Creating network trial_stack_default
Creating service trial_stack_dynamodb
Creating service trial_stack_track-count
My question is:
1) Why is the deploy service ignoring the links? I have noticed this is repeated in the docs https://docs.docker.com/engine/reference/commandline/stack_deploy/ but unsure if this will cause my stack to fail.
2) Assuming the links issue is fixed, where will any command line output be shown, to confirm the system is running? Currently I only have one node, my local machine, which is the manager.
For reference, my python image is being built by the following Dockerfile:
FROM python:3.8-slim-buster
RUN mkdir /app
WORKDIR /app
RUN pip install --upgrade pip
COPY ./requirements.txt ./
RUN pip install -r ./requirements.txt
COPY / /
COPY /resources/secrets.py /resources/secrets.py
CMD [ "python", "/main.py" ]

You can update docker-compose.yaml to enable tty for the services for which you want to see the stdout on console.
Updated docker-compose.yaml should look like this:
version: '3.3'
services:
dynamodb:
image: "amazon/dynamodb-local"
ports:
- "8000:8000"
track-count:
image: "my-app"
tty: true
links:
- "dynamodb:localhost"
and then when once you have the task deployed, to check service logs you can run:
# get the service name
docker stack services <STACK_NAME>
# display the service logs, edited based on user's suggestion
docker service logs --follow --raw <SERVICE_NAME>

how to run server using docker container?

Django server is running well in localhost. however, When I try to run server on the docker container, it doesn't find the manage.py file when using docker-compose file and even I run the container manually and run the server, it doesn't appear in browser. how can I solve this problem?
So I wrote all the code testing on my local server and using the dockerfile, I built the image of my project.
and I tried to run server on the docker container, suddenly this doesn't run.
what's worse, if I use docker-compose to run the server, it doesn't find the manage.py file though I already checked with 'docker run -it $image_name sh'
here is the code of my project
I am new to docker and new to programming.
hope you can give me a help. thanks!
file structure
current directory
└─example
└─db.sqlite3
└─docker-compose.yml
└─Dockerfile
└─manage.py
└─Pipfile
└─Pipfile.lock
Docker file
# Base image - Python version
FROM python:3.6-alpine
# Set environment variables
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1
# Set work directory
WORKDIR /code
# Copy Pipfile
COPY Pipfile /code
COPY Pipfile.lock /code
# Install dependencies
RUN pip install pipenv
RUN pipenv install --system
# Copy files
COPY . /code/
docker-compose.yml
# docker-compose.yml
version: '3.3'
services:
web:
build: .
command: python /code/manage.py runserver 0.0.0.0:8000
volumes:
- .:/code
ports:
- 8000:8000
expected result : running server in web browser like in chrome
actual result :
when using docker-compose :
ERROR like this in the prompt : web_1 | python: can't open file '/code/manage.py': [Errno 2] No such file or directory
when running the container manually with 'docker run -it $image_name sh' and 'python manage.py runserver' on the shell :
server is running but, doesn't connect to web browser. (doesn't show up in browser like chrome'

Yo have done same thing in many ways. You have copy source files using a COPY command and then you have mounted a host volume in your docker-compose.yml file. In first place you don't need a volume because volume mounts are to persisting data generated by and used by Docker containers.
Following simplified Dockerfile and docker-compose file would fix the problem.
# Base image - Python version
FROM python:3.6-alpine
# Set environment variables
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1
# Copy files
COPY . /code/
# Set work directory
WORKDIR /code
# Install dependencies
RUN pip install pipenv
RUN pipenv install --system
docker-compose.yml -:
# docker-compose.yml
version: '3.3'
services:
web:
build: .
command: python ./manage.py runserver 0.0.0.0:8000
ports:
- 8000:8000

Docker container/image running but there is no port number

I am trying to get a django project that I have built to run on docker and create an image and container for my project so that I can push it to my dockerhub profile.
Now I have everything set up and I've created the initial image of my project. However, when I run it I am not getting any port number attached to the container. I need this to test and see if the container is actually working.
Here is what I have:
Successfully built a047506ef54b
Successfully tagged test_1:latest
(MySplit) omars-mbp:mysplit omarjandali$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
test_1 latest a047506ef54b 14 seconds ago 810MB
(MySplit) omars-mbp:mysplit omarjandali$ docker run --name testing_first -d -p 8000:80 test_1
01cc8173abfae1b11fc165be3d900ee0efd380dadd686c6b1cf4ea5363d269fb
(MySplit) omars-mbp:mysplit omarjandali$ docker container ls -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
01cc8173abfa test_1 "python manage.py ru…" 13 seconds ago Exited (1) 11 seconds ago testing_first
(MySplit) omars-mbp:mysplit omarjandali$ Successfully built a047506ef54b
You can see there is no port number so I don't know how to access the container through my local machine on my web browser.
dockerfile:
FROM python:3
WORKDIR tab/
COPY requirements.txt ./
RUN pip install -r requirements.txt
COPY . .
CMD ["python", "manage.py", "runserver", "0.0.0.0"]

This line from the question helps reveal the problem;
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
01cc8173abfa test_1 "python manage.py ru…" 13 seconds ago Exited (1) 11 seconds ago testing_first
Exited (1) (from the STATUS column) means that the main process has already exited with a status code of 1 - usually meaning an error. This would have freed up the ports, as the docker container stops running when the main process finishes for any reason.
You need to view the logs in order to diagnose why.
docker logs 01cc will show the logs of the docker container that has the ID starting with 01cc. You should find that reading these will help you on your way. Knowing this command will help you immensely in debugging weirdness in docker, whether the container is running or stopped.
An alternative 'quick' way is to drop the -d in your run command. This will make your container run inline rather than as a daemon.

Created Dockerise django seed project
django-admin.py startproject djangoapp
Need a requirements.txt file outlining the Python dependencies
cd djangoapp/
RUN follwoing command to create the files required for dockerization
cat <<EOF > requirements.txt
Django
psycopg2
EOF
Dockerfile
cat <<EOF > Dockerfile
FROM python:3.6
ENV PYTHONUNBUFFERED 1
RUN mkdir /app
WORKDIR /app
ADD requirements.txt /app/
RUN pip install -r requirements.txt
ADD . /app/
EXPOSE 8000
CMD ["python", "manage.py", "runserver", "0.0.0.0:8000"]
EOF
docker-compose.yml
cat <<EOF > docker-compose.yml
version: "3.2"
services:
web:
image: djangoapp
command: python manage.py runserver 0.0.0.0:8000
ports:
- "8000:8000"
EOF
Run the application with
docker-compose up -d

When you created the container you published the ports. Your container would be accessible via port 8000 if it successfully built. However, as Shadow pointed out, your container exited with an error. That is why you must add the -a flag to your docker container ls command. docker container ls only shows running containers without the -a flag.
I recommend forgoing the detached flag -d to see what is causing the error. Then creating a new container after you have successfully launched the one you are working on. Or simply run the following commands once you fix the issue. docker stop testing_first then docker container rm testing_first finally run the same command you ran before. docker run --name testing_first -d -p 8000:80 test_1
I ran into similar problems with the first docker instances I attempted to run as well.

Using docker to compose a remote image with a local code base for *development*

I have been reading this tutorial:
https://prakhar.me/docker-curriculum/
along with other tutorials, and Docker docks and I am still not completely clear on how to do this task.
The problem
My local machine is running Mac OS X, and I would like to set up a development environment for a python project. In this project I need to run call an api from a docker repo bamos/openface. The project also has some dependencies such as yaml, etc. If I just mount my local to openface, ie:
docker run -v path/to/project:/root/project -p 9000:9000 -p 8000:8000 -t -i bamos/openface /bin/bash
Then I need to install yaml and other dependencies, and every time I exit the container the installations would be lost. Additionally, it is also much slower for some reason. So the right way to do this is using Docker compose, but I am not sure how to proceed from here.
UPDATE
In response to the comments, I will now update the problem:
Right now my Dockerfile looks like this:
FROM continuumio/anaconda
ADD . /face-off
WORKDIR /face-off
RUN pip install -r requirements.txt
EXPOSE 5000
CMD [ "python", "app.py" ]
It is important that I build from anaconda since a lot of my code will use numpy and scipy. Now I also need bamos/openface, so I tried adding that to my docker-compose.yml file:
version: '2'
services:
web:
build: .
command: python app.py
ports:
- "5000:5000"
volumes:
- .:/face-off
openface:
build: bamos/openface
However, I am getting error:
build path path/to/face-off/bamos/openface either does not exist, is not accessible, or is not a valid URL
So I need to pass bamos/openface the right way so I can build a container with it. Right now bamos/openface is listed when I do docker images.