I have created a Docker image with dockerfile where the Entrypoint is as follows:
ENTRYPOINT ["conda", "run", "--no-capture-output", "-n", "myproject", "python", "./myprojectmain.py", "--config", "./config.py"]
When I run I use the command:
docker run myproject
all is fine it seems.
However I have a secondary .py file in the root of the project called setup.py. The purpose of this file is to update some of the config and json files after getting some input from the user.
Is there a way to run this secondary file (setup.py) or do I need to create a whole new image (which seems ridiculous).
Thanks
Well... if you got an image, you don't have to use entrypoint... just run your scripts like this:
docker run image "python /some/path/myscript.py"
or
docker run image /bin/bash -c "cd /some/path && python myscript.py"
or with entry point
RUN ./myprojectmain.py --config ./config.py
RUN ./myproject2main.py --config ./config.py
ENTRYPOINT ["conda", "run", "--no-capture-output", "-n", "myproject", "python"]
You can straightforwardly provide an alternate command after the image name in the docker run command. It's harder to override the entrypoint, though. If you have both a command and an entrypoint then they are combined together into a single command.
This workflow is easiest if your Dockerfile has a CMD, and that's a complete runnable shell command. If you have an ENTRYPOINT at all, it is some kind of wrapper that does some initial setup and then runs the command it's given as additional arguments. In this particular setup, conda run with its arguments seems to meet that need and have the correct form, so you could say
ENTRYPOINT ["conda", "run", "--no-capture-output", "-n", "myproject", "--"]
CMD ["python", "./myprojectmain.py", "--config", "./config.py"]
(Note that conda run seems to have some issues; you could probably simulate it using a custom entrypoint wrapper script or use a pip-based non-virtual-environment workflow instead.)
If you split the ENTRYPOINT and CMD like this, then you can run
docker run myproject \
python setup.py
The alternate python setup.py command will be appended to the conda run entrypoint command.
... update some of the config and json files ...
It's often a good idea to inject these into your container using a bind mount. Depending on how exactly the files get set up, you may be able to initialize them from the host environment, without Docker
./setup.py
docker run -d -v $PWD/config:/app/config myproject
but if they are sensitive to the Docker environment in some way, you could do it in Docker too; make sure to mount the same configuration storage into both containers.
docker network create mynet
docker volume create config
docker run --rm --net mynet -v config:/app/config myproject ./setup.py
docker run -d -p 8000:8000 --net mynet -v config:/app/config myproject
Related
I'm using a python script for send websocket notification,
as suggested here.
The script is _wsdump.py and I have a script script.sh that is:
#!/bin/sh
set -o allexport
. /root/.env set
env
python3 /utils/_wsdump.py "wss://mywebsocketserver:3000/message" -t "message" &
If I try to dockerizing this script with this Dockerfile:
FROM python:3.8-slim-buster
RUN set -xe \
pip install --upgrade pip wheel && \
pip3 install websocket-client
ENV TZ="Europe/Rome"
ADD utils/_wsdump.py /utils/_wsdump.py
ADD .env /root/.env
ADD script.sh /
ENTRYPOINT ["./script.sh"]
CMD []
I have a strange behaviour:
if I execute docker run -it --entrypoint=/bin/bash mycontainer and after that I call the script.sh everything works fine and I receive the notification.
if I run mycontainer with docker run mycontainer I see no errors but the notification doesn't arrive.
What could be the cause?
Your script doesn't launch a long-running process; it tries to start something in the background and then completes. Since the script completes, and it's the container's ENTRYPOINT, the container exits as well.
The easy fix is to remove the & from the end of the last line of the script to cause the Python process to run in the foreground, and the container will stay alive until the process completes.
There's a more general pattern of an entrypoint wrapper script that I'd recommend adopting here. If you look at your script, it does two things: (1) set up the environment, then (2) run the actual main container command. I'd suggest using the Docker CMD for that actual command
# end of Dockerfile
ENTRYPOINT ["./script.sh"]
CMD python3 /utils/_wsdump.py "wss://mywebsocketserver:3000/message" -t "message"
You can end the entrypoint script with the magic line exec "$#" to run the CMD as the actual main container process. (Technically, it replaces the current shell script with a command constructed by replaying the command-line arguments; in a Docker context the CMD is passed as arguments to the ENTRYPOINT.)
#!/bin/sh
# script.sh
# set up the environment
. /root/.env set
# run the main container command
exec "$#"
With this use you can debug the container setup by replacing the command part (only), like
docker run --rm your-image env
to print out its environment. The alternate command env will replace the Dockerfile CMD but the ENTRYPOINT will remain in place.
You install script.sh to the root dir /, but your ENTRYPOINT is defined to run the relative path ./script.sh.
Try changing ENTRYPOINT to reference the absolute path /script.sh instead.
My folder structure looked like this:
My Dockerfile looked like this:
FROM python:3.8-slim-buster
WORKDIR /src
COPY src/requirements.txt requirements.txt
RUN pip install --no-cache-dir -r requirements.txt
COPY src/ .
CMD [ "python", "main.py"]
When I ran these commands:
docker build --tag FinTechExplained_Python_Docker .
docker run free
my main.pyfile ran and gave the correct print statements as well. Now, I have added another file tests.py in the src folder. I want to run the tests.py first and then main.py.
I tried modifying the cmdwithin my docker file like this:
CMD [ "python", "test.py"] && [ "python", "main.py"]
but then it gives me the print statements from only the first test.pyfile.
I read about docker-compose and added this docker-compose.yml file to the root folder:
version: '3'
services:
main:
image: free
command: >
/bin/sh -c 'python tests.py'
main:
image: free
command: >
/bin/sh -c 'python main.py'
then I changed my docker file by removing the cmd:
FROM python:3.8-slim-buster
WORKDIR /src
COPY src/requirements.txt requirements.txt
RUN pip install --no-cache-dir -r requirements.txt
COPY src/ .
Then I ran the following commands:
docker compose build
docker compose run tests
docker compose run main
When I run these commands separately, I get the correct print statements for both testsand main. However, I am not sure if I am using docker-composecorrectly or not.
Am I supposed to run both scripts separately? Or is there a way to run one after another using a single docker command?
How is my Dockerfile supposed to look like if I am running the python scripts from the docker-compose.yml instead?
Edit:
Ideally looking for solutions based on docker-compose
In the Bourne shell, in general, you can run two commands in sequence by putting && between them. It sounds like you're already aware of this.
# without Docker, at a normal shell prompt
python test.py && python main.py
The Dockerfile CMD has two syntactic forms. The JSON-array form does not run a shell, and so it is slightly more efficient and has slightly more consistent escaping rules. If it's not a JSON array then Docker automatically runs it via a shell. So for your use you can use the shell form:
CMD python test.py && python main.py
In comments to other answers you ask about providing this as an override in the docker-compose.yml file. Compose will not normally run a shell for you, so you need to explicitly specify it as part of the command: override.
command: /bin/sh -c 'python test.py && python main.py'
Your Dockerfile should generally specify a CMD and the docker-compose.yml often will not include a command:. This makes it easier to run the image in other contexts (via docker run without Compose; in Kubernetes) since you won't have to retype the command every different way you want to run the container. The entrypoint wrapper pattern highlighted in #sytech's answer is very useful in general and it's easy to add to a container that uses a CMD without an ENTRYPOINT; but it requires the Dockerfile to use CMD as a normal well-formed shell command.
You have to change CMD to ENTRYPOINT. And run the 1st script as daemon in the background using &.
ENTRYPOINT ["/docker_entrypoint.sh"]
docker_entrypoint.sh
#!/bin/bash
set -e
exec python tests.py &
exec python main.py
In general, it is a good rule of thumb that a container should only a single process and that essential process should be pid 1
Using an entrypoint can help you do multiple things at runtime and optionally run user-defined commands using exec, as according to the best practices guide.
For example, if you always want the tests to run whenever the container starts, then execute the defined command in CMD.
First, create an entrypoint script (be sure to make it executable with chmod +x):
#!/usr/bin/env bash
# always run tests first
python /src/tests.py
# then run user-defined command
exec "$#"
Then configure the dockerfile to copy the script and set it as the entrypoint:
#...
COPY entrypoint.sh /docker-entrypoint.sh
ENTRYPOINT ["/docker-entrypoint.sh"]
CMD ["python", "main.py"]
Then when you build an image from this dockerfile and run it, the entrypoint will first execute the tests then run the command to run main.py
The command can also still be overridden by the user when running the image like docker run ... myimage <new command> which will still result in the entrypoint tests being executed, but the user can change the command being run.
You can achieve this by creating a bash script(let's name entrypoint.sh) which is containing the python commands. If you want, you can create background processes of those.
#!/usr/bin/env bash
set -e
python tests.py
python main.py
Edit your docker file as follows:
FROM python:3.8-slim-buster
# Create workDir
RUN mkdir code
WORKDIR code
ENV PYTHONPATH = /code
#upgrade pip if you like here
COPY requirements.txt .
RUN pip install -r requirements.txt
# Copy Code
COPY . .
RUN chmod +x entrypoint.sh
ENTRYPOINT ["./entrypoint.sh"]
In the docker compose file, add the following line to the service.
entrypoint: [ "./entrypoint.sh" ]
Have you try this in your docker-compose.yaml?
version: '3'
services:
main:
image: free
command: >
/bin/sh -c 'python3 tests.py & && python3 main.py &'
both will run in the background
then run in terminal
docker-compose up --build
I downloaded a python script and a docker image containing commands to install all the dependencies. How can I run the python script using the docker image?
Copy python file in Docker image then execute -
docker run image-name PATH-OF-SCRIPT-IN-IMAGE/script.py
Or you can also build the DockerFile by using the RUN python PATH-OF-SCRIPT-IN-IMAGE/script.py inside DockerFile.
How to copy container to host
docker cp <containerId>:/file/path/within/container /host/path/target
How to copy host to the container
docker cp /host/local/path/file <containerId>:/file/path/in/container/file
Run in interactive mode:
docker run -it image_name python filename.py
or if you want host and port to be specified:
docker run -it -v filename.py:filename.py -p 8888:8888 image_name python filename.py
Answer
First, Copy your python script and other required files to your docker container.
docker cp /path_to_file <containerId>:/path_where_you_want_to_save
Second, open the container cli using docker desktop and run your python script.
The best way, I think, is to make your own image that contains the dependencies and the script.
When you say you've been given an image, I'm guessing that you've been given a Dockerfile, since you talk about it containing commands.
Place the Dockerfile and the script in the same directory. Add the following lines to the bottom of the Dockerfile.
# Existing part of Dockerfile goes here
COPY my-script.py .
CMD ["python", "my-script.py"]
Replace my-script.py with the name of the script.
Then build and run it with these commands
docker build -t my-image .
docker run my-image
We have a very small python code which we need to run on container. Following two commands are working fine ,
I want to merge them in one ? the ultimate goal is container should be up(base on image) , run python and exit by itself.
docker run --name mycontainer -v /opt/testuser/pythoncode/:/usr/src/app/ -t -d pythonimage:latest
docker exec -it mycontainer python3 /usr/src/app/subfolder/createfile.py
I tried -c "/bin/bash python3 /usr/src/app/subfolder/createfile.py" this didnt work , it just.
You can add a file called Dockerfile (with no dot before or after file name, exactly this one) with the below contents:
from ubuntu:20.04
env run=/usr/src/app/subfolder/createfile.py
cmd ["/bin/bash", "-c", "${run}"]
Then run:
docker build YOUR_IMAGE_NAME # this should be a new name, like pythonimage2
Now run it:
docker run --name mycontainer -v /opt/testuser/pythoncode/:/usr/src/app/ -t -d pythonimage2:latest
So, now the docker executing command which makes container running is now /usr/src/app/subfolder/createfile.py.
Regarding your answer, you can add a variable and each time just modify that line.
Even you can do this to your Dockerfile:
from ubuntu:20.04
env path=/usr/src/app/subfolder/
env file=$path/createfile.py
cmd ["/bin/bash", "-c", "${file}"]
Now you just need to modify file variable. If any of your sub-directories changes, you can remove that from path variable and add it to file variable.
I have been struggling to add env variables into my container for the past 3 hrs :( I have looked through the docker run docs but haven't managed to get it to work.
I have built my image using docker build -t sellers_json_analysis . which works fine.
I then go to run it with: docker run -d --env-file ./env sellers_json_analysis
As per the docs: $ docker run --env-file ./env.list ubuntu bash but I get the following error:
docker: open ./env: no such file or directory.
The .env file is in my root directory
But when running docker run --help I am unable to find anything about env variables, but it doesn't provide the following:
Usage: docker run [OPTIONS] IMAGE [COMMAND] [ARG...]
So not sure I am placing things incorrectly. I could add my variables into the dockerfile but I want to keep it as a public repo as it's a project I would like to display.
Your problem is wrong path, either use .env or ./.env, when you use ./env it mean a file named env in current directory
docker run -d --env-file .env sellers_json_analysis