#+TITLE: Pluto standalone

This is a nix derivation that wraps a version of julia with the packages
(and their dependency closure) defined in ~Packages.toml~; currently
this is just Pluto. It also provides a little julia script that will
activate this packageset (called a "julia depot"), and then start a
Pluto notebook server on port 9999. Note that it does so without setting
up any kind of authenticaton, so don't expose that port!

* TODOs
- [ ] add more packages
- [ ] more sensible auth
- [ ] working precompilation; this would probably allow running this
  without a writable julia depot

* Steps to reproduce / update the julia-to-nix part of this:

In general, it is enough to follow the readme of julia2nix, but since
that has a bunch of unstated assumptions and weird failure modes, here's a rough outline of how to actually do it:
 - using julia's package managing mode, make changes to ~Packages.toml~
   and ~Manifest.toml~. Be sure to use the same version of julia that
   will run on hainich (currently the ~julia_15~ package of
   nixpkgs-unstable), as otherwise hashes may be different
 - clone https://github.com/thomasjm/julia2nix somewhere
 - run ~julia2nix~ to generate the nix derivations
   + unfortunately, jula2nix assumes that nixpkgs-unstable is available
     as ~<nixpkgs>~ from within nix; it may fail if you are on another
     channel. In that case, there seems to be no better solution than grepping for occurences of "<nixpkgs>" in jula2nix and replacing
     them with some other path that has the required version
   + this will re-generate all the ~*.nix~ files in this directory, and
     probably reset all options. The defaults are reasonably sensible,
     but make sure to disable the ~precompile~ option in ~default.nix~
     (see below for why)
 - run ~nix-build --no-out-link~ to check if it worked and nix can
   build the julia depot
 - deploy hainich. Note that the derivation will only contain the
   package sources, not a compiled version. Julia will compile packages
   on startup (and cache them for subsequent runs), so after the deploy
   it may take a minute or two to actually run Pluto

* precompilation
/In theory/, we should be able to precompile all the packages during
nix-build, and then directly load them into julia and runtime.
However, this currently fails, and even if precompiled packages are
present in the depot built via nix, julia will refuse to use them and
recompile them instead (in a second julia depot that is writable at
runtime).

There's an open issue on this at jula2nix:
  https://github.com/thomasjm/julia2nix/issues/22