1 files changed, 87 insertions, 0 deletions
diff --git a/modules/nixos/postgresql.nix b/modules/nixos/postgresql.nix
new file mode 100644
index 0000000..df05e7e
--- /dev/null
+++ b/modules/nixos/postgresql.nix
@@ -0,0 +1,87 @@
+{
+  config,
+  lib,
+  pkgs,
+  this,
+  ...
+}:
+with lib; let
+  cfg = config.nixfiles.modules.postgresql;
+in {
+  options.nixfiles.modules.postgresql = {
+    enable = mkEnableOption "PostgreSQL";
+
+    package = mkOption {
+      type = types.package;
+      default = pkgs.postgresql_15;
+      description = "PostgreSQL package to use.";
+    };
+
+    extraPostStart = mkOption {
+      type = with types; listOf str;
+      default = [];
+      description = ''
+        Additional post-startup commands.
+
+        This could be used to provide a crude interface to grant permissions and
+        such.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    assertions = [
+      {
+        assertion = any (x: x == "en_GB.UTF-8/UTF-8") config.i18n.supportedLocales;
+        message = "The locale must be available";
+      }
+    ];
+
+    services = {
+      postgresql = {
+        enable = true;
+
+        inherit (cfg) package;
+
+        initdbArgs = [
+          "--encoding=UTF8"
+          "--locale-provider=icu"
+          "--icu-locale=en_GB@collation=posix"
+          "--locale=en_GB.UTF-8"
+          "--lc-collate=C"
+          "--lc-ctype=C"
+        ];
+
+        authentication = ''
+          local all all trust
+        '';
+      };
+
+      prometheus.exporters.postgres = {
+        enable = true;
+        listenAddress = mkDefault this.wireguard.ipv4.address;
+        port = mkDefault 9187;
+      };
+    };
+
+    systemd.services.postgresql.postStart =
+      optionalString (cfg.extraPostStart != [])
+      concatStringsSep "\n"
+      cfg.extraPostStart;
+
+    environment.sessionVariables.PSQLRC = toString (pkgs.writeText "psqlrc" ''
+      \set QUIET 1
+
+      \timing
+      \x auto
+      \pset null '[NULL]'
+      \set PROMPT1 '%[%033[1m%]%M %n@%/%R%[%033[0m%]% λ '
+      \set PROMPT2 '    … > '
+      \set VERBOSITY verbose
+      \set HISTCONTROL ignoredups
+      \set HISTFILE /dev/null
+
+      \unset QUIET
+    '');
+  };
+}