Issue
I can't copy the file from the host into the container using the Dockerfile, because i'm simply not allowed to, as mentioned in Docker Documentation:
The path must be inside the context of the build; you cannot COPY ../something /something, because the first step of a docker build is to send the context directory (and subdirectories) to the docker daemon.
I'm also unable to do so from inside jenkins job, because the job commands run inside the shell of the docker container, there is not way to talk to the parent(which is the jenkins host).
This jenkins plugin could have been a life saver, but as mentioned in the first section: distribution of this plugin has been suspended due to unresolved security vulnerabilities.
Solution
This is how I copy files from host to docker image using Dockerfile
I have a folder called tomcat
Inside that, I have a tar file and Dockerfile
Commands to do the whole process just for understanding
$ pwd
/home/user/Documents/dockerfiles/tomcat/
$ ls
apache-tomcat-7.0.84.tar.gz Dockerfile
Sample Docker file:
FROM ubuntu_docker
COPY apache-tomcat-7.0.84.tar.gz /home/test/
...
Docker commands:
$ docker build -it testserver .
$ docker run -itd --name test1 testserver
$ docker exec -it bash
Now you are inside docker container
# ls
apache-tomcat-7.0.84.tar.gz
As you can see I am able to copy apache-tomcat-7.0.84.tar.gz from host to Docker container.
Notice the Docker Documentation first line which you have shared
The path must be inside the context of the build;
So as long as the path is reachable during build you can copy.
Another way of doing this would be using volume
docker run -itd -v $(pwd)/somefolder:/home/test --name test1 testserver
Notice -v parameter
You are telling Docker to mount Current_Directory/somefolder to Docker's path at /home/test
Once the container is up and running you can simply copy any file to $(pwd)/somefolder and it will get copied
inside container at /home/test
Answered By - MyTwoCents