I want to run echo "tools path is: $TOOLSPATH" in my docker image but make sure the variable doesn't get expanded in my machine and sent to docker. I am not sure how to avoid variable expansion.
docker run -v `pwd`:/root -it --rm foobar echo 'tools path is: $TOOLSPATH'
> tools path is: $TOOLSPATH
docker run -v `pwd`:/root -it --rm foobar echo "tools path is: $TOOLSPATH"
> tools path is:
There is one way to run echo $VAR inside the container and print it in your terminal. You just need to pass an interpreter too.
docker run alpine sh -c 'echo my HOME: $HOME'
my HOME: /root
PS: I used alpine as a test. If sh doesn't work, you can try bash instead.
This might be helpful to you
docker run -v `pwd`:/root -it --rm foobar echo "tools path is: $TOOLSPATH"
Related
I am doing the below docker command from Jenkins pipeline
sh '#!/bin/sh -e\n' + "docker run -i -v $workspace/tests:/root/tests -w /root/tests --name test ${awsAccountNo}.dkr.ecr.${env.AWS_REGION}.amazonaws.com/${imageName}:latest testrun exec test.rb --input-file sample.yml"
where the container get a name of test
I want to make --name somewhat unique, so thought of doing it test-$RANDOM which will then give some random numbers. In an interactive shell session I am getting an output in the terminal. When trying to do that in the shell script it does not seems to work. May be some sort of usage error I think.
Can someone point me how to add suffix or prefix to a container name in docker run command inside a Jenkins shell.
Thank you
$RANDOM is a bash-specific variable, it doesn't work with /bin/sh interpreter.
sh() function uses /bin/sh by default.
Also, you need to escape $ sign for shell variables in double-quotes. To improve code readability you can multiline quotes: ```
So the script string should be
sh "#!/bin/bash ... --name test-\$RANDOM ..."
or
sh ```
#!/bin/bash
docker run -i -v $workspace/tests:/root/tests \
-w /root/tests --name test-\$RANDOM \
// ... rest parameters
```
Why is the environment variable not visible to the command that is run as the entrypoint?
Examples:
$docker run -it -e "name=JD" --entrypoint 'echo' ubuntu 'Hello $name'
Hello $name
$ docker run -it -e "name=JD" --entrypoint 'echo' ubuntu "Hello $name"
Hello
But when I start the shell the environment variable is there:
$ docker run -it -e "name=JD" ubuntu /bin/bash
root#c3e513390184:/# echo "$name"
JD
Why in the first case with the echo as entrypoint it does not find the env variable set?
First case
docker run -it -e "name=JD" --entrypoint 'echo' ubuntu 'Hello $name'
Single quotation mark always prevents string from variable expansion. Whatever you write in single quotes remains unchanged. Try echo '$PWD' in your terminal and you will see $PWD as the output. Try echo "$PWD" and you will get your working directory printed.
Second case
docker run -it -e "name=JD" --entrypoint 'echo' ubuntu "Hello $name"
Your code is being expanded before running Docker. Your shell expands whole string and then executes it. At this moment you dont have $name declared and you get it empty. That means inside container you get "Hello " command, not "Hello $name".
If you want to echo environment variable from inside container, simplest way is to wrap script into sh-file to prevent its expansion and pass this file to container.
Third case is obvious I guess and doesn't need explanation.
Here is my Dockerfile:
FROM ros:kinetic-ros-core-xenial
CMD ["bash"]
If I run docker build -t ros . && docker run -it ros, and then from within the container echo $PATH, I'll get:
/opt/ros/kinetic/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
If I exec into the container (docker exec -it festive_austin bash) and run echo $PATH, I'll get:
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
Why are the environment variables different? How can I get a new bash process on the container with the same initial environment?
The ENTRYPOINT command is only invoked on docker run, not on docker exec.
I assume that this /ros_entrypoint.sh script is responsible for adding stuff to PATH. If so, then you could do something like this for docker exec:
docker exec -it <CONTAINER_ID> /ros_entrypoint.sh bash
docker exec only gets environment variables defined in Dockerfile with instruction ENV. With docker exec [...] bash you additionally get those defined somewhere for bash.
Add this line to your Dockerfile:
ENV PATH=/opt/ros/kinetic/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
or shorter:
ENV PATH=/opt/ros/kinetic/bin:$PATH
This is old question but since it's where google directed me I thought I'll share solution I ended up using.
In your entrypoint script add a section similar to this:
cat >> ~/.bashrc << EOF
export PATH="$PATH"
export OTHER="$OTHER"
EOF
Once you rebuild your image you can exec into your container (notice bash is invoked in interactive mode):
docker run -d --rm --name container-name your_image
docker exec -it container-name /bin/bash -i
If you echo $PATH now it should be the same as what you have set in .bashrc
I want to mount a volume and add it to the container's PATH environment variable. I've tried the following and none is working.
docker run -it -v $(PWD):/app -e PATH=$PATH:/app/bin debian:jessie bash
docker run -it -v $(PWD):/app -e PATH='$PATH:/app/bin' debian:jessie bash
docker run -it -v $(PWD):/app -e PATH='$$PATH:/app/bin' debian:jessie bash
docker run -it -v $(PWD):/app -e PATH='\$PATH:/app/bin' debian:jessie bash
How do I append the mounted volume to PATH?
If you you use -e option, the $PATH value is the PATH of the host instead of the container.
You can do it like this:
docker run -it -v $(PWD):/app debian:jessie bash -c 'export PATH=$PATH:/app/bin; bash'
Within the docker command line, you can't get "what will be the value of $PATH at runtime". Thus, you cannot append a PATH to the PATH variable, with docker's -e flag. To achieve what you want to do, you will need to do that in a script that will get executed as the cmd / entrypoint of your container.
You can define a fixed Path for your imported Apps and add the new Path to the Apps into the Environment-Variable "Path"
Let's take your Path "/app". In your Dockerfile add the following Line:
ENV PATH=${PATH}:/app/bin
Build your modified Docker
Now you can access all Apps located under < external Directory >/bin that you mount to "/app" via
-v <external Directory>:/app
You can use a shell script (let's call it run.sh):
#/bin/bash
PATH=$PATH:/app/bin
"$#"
and call it from docker:
docker run -it -v $(PWD):/app debian:jessie /app/run.sh bash
I have a very simple script called as myscript.sh
echo "this is test " > /tmp/myfile.txt
echo $TEST >> /tmp/myfile.txt
I have stored this script in my disk which i plan to pass it to the container as a volume like this below
docker run -d --name test \
-v /home/docker/test/myscript.sh:/tmp/myscript.sh \
-e TESTING=just-a-test \
test
The Dockerfile looks like this below
FROM ubuntu
CMD ["bash", "/tmp/myscript.sh"]
So the thought process is to get this script executed and get the result as a file myfile.txt which would contain the -e passed.
Instead i am getting
docker#boot2docker:~/test$ docker exec -it test /bin/bash Error
response from daemon: Container test is not running
Which means that this simplest program did not execute as a container.
I Could not figure it out.
The container ran, executed the script, then exited. A container only runs as long as its main process. When that stops, the container stops.
A simpler test would be to change your test script to:
#!/bin/bash
echo $TEST
I would change your Dockerfile to copy the file in and remove the "bash" part of the CMD instruction:
FROM ubuntu
COPY myscript.sh /myscript.sh
CMD /myscript.sh
Now rebuild and run:
$ docker build -t test .
...
$ docker run -e TEST=VAL test
...
The container should echo the value of the test variable and exit. (I haven't tested any of this, so apologies for any mistakes).
The answer to this question is to use the entrypoint instead of cmd.
I did some research and i came up with the solution that looks like this
ENTRYPOINT ["bash", "<script>"]
To run the script just use
docker run -d --name [--privileged] -p : \
- v /script.sh:/tmp/script.sh \
where -v <> : YOU CAN ALSO USE THE WGET TO GET THE SCRIPT LIKE MOST PEOPLE AND EXECUTE AT RUNTIME.
Appreciate all the people who tried to solve the query