Fedora Haskell and tracking Stackage

Jens Petersen

Devconf.cz 2018, Brno (Jan 28)

I am Jens Petersen

Red Hat and Fedora

Fedora Haskell project and SIG founder

Haskell

Why Haskell and GHC?

  • Functional purity and immutability
  • Lazy evaluation
  • Statically and strongly typed
  • Good concurrency
  • Native executables
  • Garbage collected

https://www.snoyman.com/blog/2017/12/what-makes-haskell-unique

Examples of Haskell packages?

Haskell packages

  • pandoc
  • ShellCheck
  • xmonad and xmobar
  • git-annex
  • hledger
  • shake

also: ghc, Purescript, Elm, Agda and idris

Enterprise Haskell

  • Facebook
  • Banks (financial trading, etc)
  • Blockchain
  • Cardano blockchain
  • etc

Services: Well Typed, FP Complete, …

Haskell Ecosystem

Hackage

main Haskell upstream package source repository

  • cabal-install package tool
  • has revisions of dependency bounds!

Package .cabal files have detailed metadata including dependencies allowing most packages to be packaged completely automatically

Stackage

Stable consistent buildable Haskell package sets

Currently about 2600 packages

stack build tool

Fedora Haskell

Fedora Haskell challenges

currently ~450 Haskell sources packages in Fedora

GHC has strict version binary dependencies:

Lack of packaging manpower led to some deps subpackaging

Fedora Haskell Packagers

Many people have helped with packaging including:

  • Active: Elliott Sales de Andrade,
    Robert-André Mauchin, Jens Petersen

  • Packagers: Ben Boeckel, Ricky Elrod, Zach Oglesby

  • Former: Bryan O’Sullivan, Yaakov Nemoy, Conrad Meyer, Lakshmi Narasimhan, Shakthi Kannan, Michel Salim

Tools for Fedora Haskell

cabal-rpm

cabal-rpm

RPM packaging tool

  • converts Haskell package .cabal files to RPM .spec files
  • can update packages and refresh packaging

OpenSuse has also used cabal-rpm

Demo of cabal-rpm

Fedora Haskell Tools

fedora-haskell-tools

  • fhpkg
  • fhbuild
  • fhbz

Currently Fedora does not provide any easy way to query for all Haskell packages

Demo of fedora-haskell-tools

Future plans

Improvements to tools

  • improve reliability (updating and koji building)
  • async parallel building (also koji chain-build)
  • docker for local building
  • performance: caching of built package info
  • editors for .cabal and .spec files

  • push Haskell types

  • querying for Fedora (Haskell) packages
    (in the post-pkgdb world)

Distro Haskell competition

  • Nixos: all of Hackage!
  • OpenSuse: Stackage LTS

Continuous integration?

To keep Fedora in sync with Stackage LTS

Copr: build a subset of Stackage?

Koschei

Fedora CI

Fedora Haskell Contributions

Questions?

More information