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Advantages of Nix powered GRASS environment
solarized

Advantages of Nix powered GRASS environment

GRASS GIS Community Meeting, Prague, 2024

Ivan Mincik, @imincik, Nix Geospatial Team

Nix is a huge thing and sometimes looks like a magic.

Docker builds ARE (usually) repeatable, but they are NOT designed to be reproducible !

Reproducibility = the same input always returns the exactly same output.

Why Nix ?

The way for running a software on a computer.

(E. Dolstra, PhD theses, 2006)

Features of Nix

  • Reproducibility as a core feature:

    • between multiple builds
    • between multiple machines
    • over the time

  • Full control over whole dependency graph

  • No software conflicts

Features of Nix

  • Software deployment and configuration is declarative (using Nix lang. and/or CLI)

  • Software versions are locked forever or updated only when requested

  • Runs on all Linux, Mac, Win WSL 2

  • Dozens of other very unique features

Advantages for Geospatial users ?

  • Isolated envs for all types of project components (CLI, GUI, DBs, services, languages, scripts)

  • All components are consistently built together (same GDAL for Python, QGIS, PostGIS, ...)

  • Each project can use different versions of software

  • Great customization support

Advantages for GRASS users ?

Reproducibile environments

... should be mandatory for researchers and scientists.

What is Nix ?

  • Nix - the package manager/build system
  • Nix - the language
  • Nixpkgs - the largest packages repo
  • Nix modules system - the declarative configuration management
  • NixOS - the unique operating system

+ dozens of other community projects (Home Manager, ..)

What is Geospatial NIX ?

  • Geo and non-geo software repository

  • Isolated and reproducible environment for geospatial projects

  • Runs on all Linux distros, (Mac) and in containers

Components of Geospatial NIX ?

DEMO

(magic Nix one-liners)

Run GRASS

  • No GRASS installed

    $ grass

The program 'grass' is not in your PATH.

  • Run GRASS from Internet repo (geospatial-nix)

    $ rm -rf ~/grassdata  # note to myself

$ nix run github:imincik/geospatial-nix#grass -- --text -c EPSG:4326 -e ~/grassdata/world_latlong_wgs84

$ nix run github:imincik/geospatial-nix#grass -- --version

GRASS GIS 8.3.2

Run GRASS (other version)

  • Run GRASS in other version

    $ nix run github:imincik/geospatial-nix/58d8cff#grass -- --version

GRASS GIS 8.3.1

Shell environment

  • No QGIS installed

    $ qgis

The program 'qgis' is not in your PATH.

  • Create shell environment with GRASS and QGIS

    $ nix shell github:imincik/geospatial-nix#{grass,qgis}

$ grass --version
GRASS GIS 8.3.2

$ qgis --version
QGIS 3.36.3-Maidenhead 'Maidenhead' (exported)

Which GRASS ?

  • Which GRASS and QGIS ?

    $ which grass
/nix/store/4gngq1xaiimh953d85w6kay9jgr904cm-grass-8.3.2/bin/grass

$ ls /nix/store/<HASH>-grass/

  • Show package dependencies

    $ nix derivation show github:imincik/geospatial-nix#grass

  • Exit shell environment

    $ exit  # no grass anymore :(

GRASS package

GRASS customization 1

  • Modify build dependencies (latest GDAL from master)

    $ nix run -L --impure --expr \
  "let \
    f = builtins.getFlake "github:imincik/geospatial-nix"; \
    p = f.packages.x86_64-linux; \
  in p.grass.override { gdal = p.gdal-master; }"

$ g.version -e

GRASS 8.3.2 (2024)
PROJ: 9.4.1
GDAL/OGR: 3.10.0dev
GEOS: 3.12.1
SQLite: 3.43.2

GRASS customization 2

  • Modify build configuration (no X support)

    $ nix run -L --impure --expr \
  "let \
    f = builtins.getFlake "github:imincik/geospatial-nix"; \
    p = f.packages.x86_64-linux; \
  in p.grass.overrideAttrs (old: { configureFlags = old.configureFlags ++ [ \"--without-x\" ]; })"

GRASS in container

  • Nix is a better Docker image builder than Docker

    $ nix build --impure --expr \
  "let \
    f = builtins.getFlake "github:imincik/geospatial-nix"; \
    p = f.packages.x86_64-linux; \
    np = f.inputs.nixpkgs.legacyPackages.x86_64-linux; \
  in np.dockerTools.buildImage \
    { name = \"grass\"; config.Cmd = [ \"\${p.grass}/bin/grass\" \"--version\" ]; }"

$ docker load < ./result

$ docker run grass:<TAG>

GRASS development environment 1

  • Get GRASS source code

    $ mkdir grass-dev && cd grass-dev

$ git clone git@github.com:imincik/grass.git code
$ cd code

$ git checkout nixfile  # branch containing flake.nix

  • Build GRASS from source

    $ nix develop

$ ./configure

$ make -j8

GRASS development environment 2

  • Automatically enable the environment

    $ echo "use flake" > .envrc

$ direnv allow

https://direnv.net/

GRASS development version

  • Run latest GRASS development version

    $ nix run github:imincik/grass/nixfile#grass -- --text

GRASS addons (current WIP)

  • Launch GRASS with addons

    $ export GRASS_ADDON_BASE=$(\
    nix build --print-out-paths github:imincik/geospatial-nix/grass-addons-package#grass-plugin-r-hydrodem
  )
  
$ nix run github:imincik/geospatial-nix#grass -- --text --exec r.hydrodem

GRASS module (current WIP)

  • GRASS Geospatial NIX module

      # https://github.com/imincik/grass-addons-module/blob/master/geonix.nix

  applications.grass = {
    enable = true;
    plugins = p: [ 
        geopkgs.grass-plugin-r-hydrodem
        geopkgs.grass-plugin-v-histogram
    ];
  };

Geospatial NIX.today

Nix documentation