rebar eunit can't find include lib in erlang:latest docker container

Question

I'm new to docker and erlang. I've installed docker and VSCode on my windows machine and I want to learn to develop erlang in the container, so I created Dockerfile:

FROM erlang:latest

WORKDIR /project

COPY . .

and .devcontainer directory with devcontainer.json file:

{
    "name": "Erlang dev container",
    "context": ".",
    "dockerFile": "Dockerfile",
    "settings": { 
        "terminal.integrated.shell.linux": "/bin/bash"
    },
    "extensions": []
}

After I opened my project folder in container I can issue bash commands and I can start erl but when I try to ask rebar to test my code with

rebar eunit

or

rebar3 eunit

I get error:

can't find include lib "eunit/lib/eunit.hrl"

What did I do wrong? Is the erlang:latest image supposed to be used for erlang development? How to fix it?

Answer 1

In order to use eunit, when I run erlang programs in the shell (not using docker), I use the following -include_lib directive:

-include_lib("eunit/include/eunit.hrl").

You seem to be using a different path:

 eunit/lib/eunit.hrl

in container I can issue bash commands

Then use bash commands to search for the file eunit.hrl.

You can always just copy the file eunit.hrl and put it in the src directory of your rebar project, then in your module use:

-include("eunit.hrl")

I'm new to docker and erlang.

If worst comes to worst, don't worry about eunit. There is a lot to learn about erlang before you will need a testing framework.