CODEWITHSUNDEEP
dockerjupyterihaskell
Nick Tchayka
Nick Tchayka

Reputation: 573

Additional steps in Dockerfile

I have a Docker image which is a server for a web IDE (Jupyter notebook) for Haskell.

Each time I want to allow the usage of a library in the IDE, I have to go to the Dockerfile and add the install command into it, then rebuild the image.

Another drawback of this, I have to fork the original image on Github, not allowing me to contribute to it.

I was thinking about writing another Dockerfile which pulls the base one with the FROM directive and then RUNs the commands to install the libraries. But, as they are in separate layers, the guest system does not find the Haskell package manager command.

TL;DR: I want to run stack install <library> (stack is like npm or pip, but for Haskell) from the Dockerfile, but I dont want to have a fork of the base image.

How could I solve this problem?

Upvotes: 1

Views: 115

Answers (1)

Christoph Burschka
Christoph Burschka

Reputation: 4689

I was thinking about writing another Dockerfile which pulls the base one with the FROM directive and then RUNs the commands to install the libraries. But, as they are in separate layers, the guest system does not find the Haskell package manager command.

This is indeed the correct way to do this, and it should work. I'm not sure I understand the "layers" problem here - the commands executed by RUN should be running in an intermediate container that contains all of the layers from the base image and the previous RUN commands. (Ignoring the possibility of multi-stage builds, but these were added in 17.05 and did not exist when this question was posted.)

The only scenario I can see where stack might work in the running container but not in the Dockerfile RUN command would be if the $PATH variable isn't set correctly at this point. Check this variable, and make sure RUN is running as the correct user?

Upvotes: 0

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