I am very new to docker, and I need help to dockerize a ruby script that takes a a input directory and output directory.
i.e generate_rr_pair.rb BuildRR -n /data/ -o /output
What the script does, is it will take the -n option (input) and check if the directory exists, if it does it uses the files inside as input. The script will then output data to the -o option (output). If the output directory doesn't exist, the script will create the directory and output files there.
How can I create a Dockerfile to handle this? Should I pass these in, as environment variables? Or should I use mounted Volumes? But since the script handles fileIO, I am not sure if I want volumes. The input directory should already exist on the host, and the output directory will get created. Both directories, should remain after docker container stops.
Use the official ruby image in your docker file:
FROM ruby:2.1-onbuild
CMD ["ruby", "generate_rr_pair.rb"]
Building the container as normal
docker build -t myruby .
Which can then be run as follows:
docker run --rm -it -v /data:/data -v /output:/output myruby BuildRR -n /data -o /output
Note that volume mappings are required if you want the ruby script within the container to operate on directories mounted on the host machine.
Related
I am trying to copy a folder outside of a container using docker cp, but I am running in an unexpected issue: the command works perfectly outside of a shell script yet fails when running the script.
For example: copy_indices.sh
for x in "${find_container_id_arr[#]}"; do
CONTAINER_NAME="${x}"
CONTAINER_ID=$(docker ps -aqf "name=${x}")
idx_name=$(docker exec -it "$CONTAINER_ID" ls -1 /usr/share/elasticsearch/data/nodes/0/indices)
docker cp "$CONTAINER_ID":/usr/share/elasticsearch/data/nodes/0/indices/"$idx_name" "$ALL_INDICES"/"$idx_name"
done
I determine the container ID using CONTAINER_ID=$(docker ps -aqf "name=${x}"), find the name of folder I need using idx_name=$(docker exec -it "$CONTAINER_ID" ls -1 /usr/share/elasticsearch/data/nodes/0/indices) and then copy it on the host filesystem: docker cp "$CONTAINER_ID":/usr/share/elasticsearch/data/nodes/0/indices/"$idx_name" "$ALL_INDICES"/"$idx_name"
My issue is that every command evaluates and run as expected when not put inside this script. I can run the command docker cp <my_container>:/usr/share/elasticsearch/data/nodes/0/indices/<index_name> ./all_indices/<index_name> and the target folder is indeed found and copied onto the host.
Once these commands are inside a script however, I get an "Error: No such container:path:" error and I can't pinpoint what is going wrong, because the mentionned path indeed exists in the container and the container is correct as I tested it running the "final" command supposed to be executed (the docker cp one).
What could be the reason these commands suddenly stop working when put in a shell script?
I am trying to run a local script with docker bash in windows PowerShell but not working.
My script part is another program, but the finally goal is to process a media file and zip it with the shell script.
The cmd: docker exec -it containername /bin/bash < myscript.sh -f fileone.mp4 -h output
I have an error in ps:
The '<' operator is reserved for future use.
The parameters (and also the files) are changing, if rerun the shell script, and after the script, processing is done it will create a zip file (what I need) with the output name, but random strings will be placed to the zipped filename too.
Anyone tried to use docker in that way in windows?
I figure out a solution for my own question. I just leave it here, if someone needs it.
The docker-compose file:
version: '3.8'
services:
somename:
build:
context: .
dockerfile: Dockerfile
container_name: 'name_if_you_need'
The dockerfile:
FROM debian:latest
# Install and/or config anything what you need
ADD . /newfolder
WORKDIR /newfolder
ENTRYPOINT [ "/newfolder/myscript.sh" ]
To call (with arguments and/or flags if your script need it): docker run --rm -v ${PWD}:/newfolder image_name -flag1 sample.mp4 -flag2 sample (no tty error, not need winpty)
Please note, if your script working with file or files, and you pass it via arguments like me, you need to copy them in your current folder before docker run
With this solution, if your script generates a file or files when/after executing, you will see them automatically in your current folder.
I am a newbie in Docker. I introduced the Docker environment in WSL2 (Windows10Home). I do not wish to use the VSCode for simpler implementation. I would like to rather use the Ubuntu terminal. When I try to compile my LaTeX file (my_input.tex) with a Docker image (https://hub.docker.com/r/weichuntsai/texlive-small), but it complains that there is no such a tex file.
docker run --name mylatex -dt -v /home/myname:/home weichuntsai/texlive-small:1.1.0
When I send the following command in the terminal, he complains of no corresponding file.
txrun my_input.tex xelex, although I created this tex file in the home
(~, or home/myname) directory.
Sending ls returns tex.mf only without showing my_input.tex unfortunately.
Sending pwd returns root with some reasons. I have no idea why it returns root, not home/myname.
It may be due to my insufficient understanding of Docker, but I appreciate your kind advice on
that question.
N.B. I became to know that Docker images are located in /var/lib/docker.
To change this directory, one must stop the Docker daemon with
sudo service docker stop. Then one must edit /etc/docker/daemon.json.
{
"data-root": "/to/some/path"
}
Checking Dockerfile of your image shows that working directory is root https://hub.docker.com/r/weichuntsai/texlive-small/dockerfile
Just mount your home to container root:
docker run --name mylatex -dt -v /home/myname:/root weichuntsai/texlive-small:1.1.0
OR inside container change to home by cd /home
Checking Dockerfile of your image shows that working directory is root https://hub.docker.com/r/weichuntsai/texlive-small/dockerfile
Just mount your home to container root:
docker run --name mylatex -dt -v "/home/me":"/file" weichuntsai/texlive-small:1.1.0
OR inside container change to home by cd /home
and then you access your file like
docker exec -it mylatex bash
cd /file
ls
I am a docker beginner. I have used this SO post to run a shell script with docker run and this works fine. However, what I am trying to do is to apply my shell script to a file that lives in my current working directory, where Dockerfile and script are.
My shell script - given a file as an argument, return its name and the number of lines:
#!/bin/bash
echo $1
wc -l $1
Dockerfile:
FROM ubuntu
COPY ./file.sh /
CMD /bin/bash file.sh
then build and run:
docker build -t test .
docker run -ti test /file.sh text_file
This is what I get:
text_file
wc: text_file: No such file or directory
I'm left clueless why the second line doesn't work, why the file can't be found. I don't want to copy my text_file to the container. Ideally, I'd like to run my script from docker container on any file in my current working directory.
Any help will be much appreciated.
Thanks!!
You're building your Docker image containing the script /file.sh. Still, your Docker container does not contain (or know) about the file text_file which you're passing as an argument.
In order to make it known to your Docker container, you have to mount it when running the container.
docker run --rm -it -v "$PWD"/text_file:/text_file test /file.sh /text_file
In order to check for other files, you just have to swap text_file in both the mount and the argument.
Notes
In addition to Docker volume mounts, I might suggest some more improvements to spice up your image.
In order to run a script, you don't have to use ubuntu as your base image. You might be fine with alpine or even more focused bash. And don't forget to use tags in order to enforce the exact same behavior over time.
You can set your script as an ENTRYPOINT of your Dockerfile. Then, your only specifying the script name (text_file in that case) as your command.
When mounting files, you can change the name of the file in your container. Therefore, you can simplify your script and just mounting the file to test at the exact same place every time you run the container.
FROM alpine:3.10
WORKDIR /tmp
COPY file.sh /usr/local/bin/wordcount
ENTRYPOINT /usr/local/bin/wordcount
CMD file
Then,
docker run --rm -it -v "PWD"/text_file:/tmp/file test
will do the job.
I want to be able to pipe some content into a docker process without clobbering it's stdin.
I thought I could do this by opening a new file descriptor in bash before spawning the docker process, then consuming this descriptor within the docker process. However it doesn't work
outside docker:
exec 4<>somefile.txt
docker run --rm -i image cmd args > output.txt
inside docker:
exec 4>file.txt # also tried without the exec
do something with file.txt
The docker container stops when it reaches the 4>file.txt line.
It must be an atomic action, so I can't use docker cp or anything like that.
Also, the docker image does not expose any network ports, so netcat cannot be used.
I would prefer to not use any complex docker mounts.
STDIN is required for other purposes, so I can't clobber that
Are there any other options for getting the file content into a transient container for the use of a single command?
The usual approach here is to mount the current directory into the container. You can choose any directory name inside the container, and should try to avoid hiding the script itself with the mount.
docker run --rm -i -v $PWD:/data image \
cmd -i /data/file.txt -o /data/output.txt --other-args
Filesystem permissions can be tricky, on both sides of this: you can name any directory in the first half of the -v option, even system directories like /etc; and if the process inside the container runs as a non-root user it might have trouble reading the files in the directory you mount in.
You can bind-mount either files or directories, but with the one caveat that they must exist on the host first, or else Docker will create a directory for you (even if you wanted a file; and likely owned by root and not your local user).