Adding an extension for Postgres

[idontgetoutmuch]

I think I answered my own question but it may still be of interest - I wanted to add audits to a postgres server but the https://github.com/pgaudit/pgaudit extension wasn’t available so I wrote this https://github.com/NixOS/nixpkgs/pull/208250.

I have several questions:

• It wasn’t clear to me which arguments(?) were needed to build the package other than running the nix and getting an error. Even then it wasn’t obvious I needed kerberos: error: Function called without required argument "krb" at /Users/dom/nixpkgs/pkgs/servers/sql/postgresql/ext/pgaudit.nix:1, did you mean "arb", "grb" or "k3b"?

• https://github.com/NixOS/nixpkgs/pull/208250/files#diff-b14917f724238c95c3cbc09f6d71504d240da722d61661acfd00a2f146f128d1R21 I didn’t add this at first but corrected the error. How would I know to add it?

• The PR always asks for lots of information and I have no idea how to answer. I think I should have named my PR or my commit message differently at least but which one?

• I seem to have to have my own copy of nixpkgs to test the PR. Obviously I need that at the end but do I really have to build everything when I am just experimenting? Is there a way of testing my derivation(?) with my current set of packages?

• I am testing / using my derivation as below but is this a good way of using it? Caveat: I know little about postgres.

{ nixpkgs ? import <nixpkgs> { } }:

nixpkgs.stdenv.mkDerivation {
  name = "test pgaudit";

  buildInputs = [
    nixpkgs.libintlOrEmpty
    (nixpkgs.postgresql_13.withPackages (p: [ p.pgaudit ]))
    nixpkgs.darwin.apple_sdk.frameworks.Cocoa
  ];

  postgresConf =
  nixpkgs.writeText "postgresql.conf"
    ''
      # Add Custom Settings
      logging_collector = on
      log_directory = 'pg_log'
      shared_preload_libraries = 'pgaudit'
    '';

  # ENV Variables
  PGDATA = "${toString ./.}/.pg";

  # Post Shell Hook
  shellHook = ''
    echo "Using ${nixpkgs.postgresql_13.name}."

    # Setup: other env variables
    export PGHOST="$PGDATA"
    # Setup: DB
    [ ! -d $PGDATA ] && pg_ctl initdb -o "-U postgres" && cat "$postgresConf" >> $PGDATA/postgresql.conf
    pg_ctl -o "-p 5555 -k $PGDATA" start
    alias fin="pg_ctl stop && exit"
    alias pg="psql -p 5555 -U postgres"
  '';
}

[infinisil]

We looked at some of these questions in Nix Hour #21 :)

[infinisil]

Closing for now, let me know if you have questions that aren't addressed!