Is WSL (Windows Subsystem for Linux) supported?

[Wizek]

I was able to install nix by itself. Then when I tried to ./try-reflex, I got the following error.

root@DESKTOP:~/reflex-platform# ./try-reflex
If you have any trouble with this script, please submit an issue at https://github.com/reflex-frp/reflex-platform/issues
It looks like your filesystem's root directory is writable by the current user.  This will cause nix to fail building try-reflex, and may also indicate a security vulnerability.  Note that you should not run try-reflex as root.
To fix this problem, please use your operating system's "repair permissions" feature, if it has one, or manually remove write permissions for your user from the '/' directory.

root@DESKTOP:~/reflex-platform#

So I've created a non-root user inside WSL, set a password for it, added it to sodoers list, changed to it, reinstalled nix under it and now try-reflex install is purring along nicely. I intend to update this post with followup questions if I encounter any more roadblocks, or a note of success otherwise, hopefully to benefit others who are looking to find out if reflex can be built with Windows or WSL.

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Misc:

Windows 10 build version: 15063.674
Related issue: #116 (comment)

[3noch]

Last I knew GHC builds on WSL were horrendously slow. I think Nix's heavy use of dynamic linking does not play well with WSL. However, that's just a theory. Interested in what you find.

[Wizek]

I can vouch for slowness so far. About 3-4 hours and counting. Building single modules seems to take GHC minutes instead of seconds. Let's see where this goes. I hope I won't have to run this for weeks; fingers crossed.

Edit: This issue may be related: microsoft/WSL#1671

[Wizek]

Great Success!

After being fed up with the slowness I snooped around, and it turns out I just needed some windows updates (fall creators update, v1709). After that nix+ghc was much faster, near native AFAICT.

I also needed to install VcXsrv, and set some other settings that I am likely not remembering in my sleepiness currently -- but wanted to share the good news before going to bed. If anyone hits an error please say so and I'll see if I've encountered it or not; and if so, how I fixed it.

[3noch]

Wow! Awesome!

[ryantrinkle]

This is really awesome! Thanks for trying it out, @Wizek

[zarybnicky]

@Wizek I'm wondering how you managed to do that, as on my system, building ghc-8.0.2-with-packages fails - I've managed to track down the issue to microsoft/WSL#2229 (also tracked in microsoft/WSL#2443 and NixOS/nixpkgs#27808). Debugging syscalls is however a bit outside of my experience, so I guess that I'll switch back to a NixOS VM in the meantime...
(I'm using Insider Build v17025)

[ali-abrar]

Should this issue be closed, or are there some changed to reflex-platform that we ought to make as a result of the above? Thanks!

[zarybnicky]

I've tried again, but this time I got stuck on installing Nix inside WSL - I ran into NixOS/nix#1785, but despite having Insider Builds enabled, I'm only on v17074 (compared to v17084 that seems to solve it). I'll try to enable the fast-track for Insider builds, but it might take a while.

The issue I ran into before, assuming that the problem still exists, seems to be resolved by modifying lndir - either patching the executable, or replacing it with e.g. https://opensource.apple.com/source/X11/X11-0.46.4/lndir.sh (one suggested replacement)

[zarybnicky]

Trying again after switching to fast-track insider builds - I'm on v17115 now and ./try-reflex works OK. reflex-todomvc exits with 'cannot open display', but that is simply a case of missing VcXsrv, and ghcjs compilation works just fine.
So @ali-abrar, I think it's fine to close this issue - despite the fact that microsoft/WSL#2229 is still open, it seems that whatever Nix does now works well enough.

[ali-abrar]

Thanks, @zarybnicky.