What is the proper way to select a Sandbox?

[shp7724]

Hi,

I'm completely new to Ocaml and trying to set up ocaml environment for vscode.
Especially I'm having a hard time with setting up this vscode extension to detect ocamllsp.

$ opam switch
#  switch   compiler      description
→  default  ocaml.4.12.0  default

$ which ocamllsp
/Users/shp7724/.opam/default/bin/ocamllsp

I assume this has to do with Sandbox and the issue #430. However, I couldn't find any documentation on how to set the opam sandbox to default.

Obviously the following setting does not work.

{
  "ocaml.sandbox": {
    "kind": "custom",
    "switch": "default"
  }
}

What is the proper way to select the default sandbox?
Thank you.

[mnxn]

The correct JSON would be

"ocaml.sandbox": {
  "kind": "opam",
  "switch": "default"
}

However, the intended way to change the sandbox is through the command or status bar item: https://github.com/ocamllabs/vscode-ocaml-platform#setting-up-the-extension-for-your-project

[shp7724]

I tried both way (JSON and the command), but still it prints these warnings:

An error occurred starting the language server `ocamllsp`. Sandbox initialization failed: `ocaml-lsp-server` is not installed in the current sandbox.

OCaml bytecode compiler `ocamlc` was not found in the current sandbox. Do you have OCaml installed in the current sandbox?

I tried:

1. Command Palette > Ocaml: Select a Sandbox for this Workspace > Global: does not work.
2. Command Palette > Ocaml: Select a Sandbox for this Workspace > Custom: have no idea what to input as a custom command template.

Is there anything else that I can try? Or can you provide some relevant docs on custom command template?

[mnxn]

I think your environmental variables aren't being set correctly. You can try running opam init in a terminal which should prompt you to update your shell configuration.

For a custom command template it shows you a default value:

To make it use absolute paths you could try changing it to /Users/shp7724/.opam/default/bin/$prog $args. However, you will have a better integrated experience with an opam sandbox.

[shp7724]

I'm afraid I've already run opam init before.
Could you tell me how to verify my environmental variables setup?

These are the warnings that I have.

[mnxn]

You're right, it looks like your .zshrc file already has the necessary command.

Can you please paste the contents of OCaml Platform Extension output channel here?
Do Cmd+Shift+P and use the OCaml: Show OCaml Platform Extension Output command to open the output channel.

[shp7724]

The problem was that I was using code-server, which is basically a fork of vscode, and for some reason the environment variables are ignored when the server is started.

So I added following lines to the startup script of code-server and everything worked as expected.

# OCaml Platform Extension Configuration
[[ ! -r /Users/shp7724/.opam/opam-init/init.zsh ]] || source /Users/shp7724/.opam/opam-init/init.zsh  > /dev/null 2> /dev/null
export PATH="/Users/shp7724/.opam/default/bin:/usr/local/bin:$PATH"

@mnxn Thanks for helping me find the solution.

[mnxn]

I'm not very familiar with code-server, so I'm not sure why that happens, but I'm glad you found a workaround.

Let us know if you have any other questions.

[Khady]

I'm guessing that the problem is the same as with vscode remote ssh. code-server is probably started in a non interactive session.

you can see in ~/.opam/opam-init/init.sh there are some lines protected by an if block.

if [ -t 0 ]; then
  test -r /home/louis.roche/.opam/opam-init/complete.sh && . /home/louis.roche/.opam/opam-init/complete.sh > /dev/null 2> /dev/null || true

  test -r /home/louis.roche/.opam/opam-init/env_hook.sh && . /home/louis.roche/.opam/opam-init/env_hook.sh > /dev/null 2> /dev/null || true
fi

test -r /home/louis.roche/.opam/opam-init/variables.sh && . /home/louis.roche/.opam/opam-init/variables.sh > /dev/null 2> /dev/null || true

By default during opam init, opam will modify ~/.profile to source ~/.opam/opam-init/init.sh. It works fine when creating an interactive session with ssh louis@myserver. But it doesn't work flawlessly with vscode's remote ssh mode. What I mean by that is if I remote ssh with vscode on my server and open a shell inside vscode, then inside this shell navigate to a folder with a local switch, I get a warning from opam

[WARNING] The environment is not in sync with the current switch.
          You should run: eval $(opam env)

I don't have this warning when I ssh by hand on the server.

It can be solved by sourcing ~/.opam/opam-init/init.sh from ~/.bashrc instead of ~/.profile.