From b5442f6657d4245866104989a1f75ec0a5fe06ed Mon Sep 17 00:00:00 2001
From: Stefan Kreutz <mail@skreutz.com>
Date: Thu, 16 Apr 2026 15:22:51 +0200
Subject: Add PostgreSQL version-specific Nix packages

---
 CHANGELOG.md             |  4 ++++
 README.md                |  6 +++++
 examples/nixos/flake.nix |  7 +++++-
 flake.nix                | 58 +++++++++++++++++++++++++++++++-----------------
 4 files changed, 54 insertions(+), 21 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6d61e20..2ddeb67 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,10 @@ The format is based on [Keep A Changelog][] and this project adheres to [Semanti
 
 ## Unreleased
 
+### Added
+
+* Added PostgreSQL version-specific packages to Nix flake
+
 ## [0.3.0] - 2026-04-16
 
 ### Added
diff --git a/README.md b/README.md
index 07aae60..599c083 100644
--- a/README.md
+++ b/README.md
@@ -96,6 +96,12 @@ Alternatively you can run or install the experimental Nix flake:
 nix run git+https://git.skreutz.com/temp-postgres.git -- --help
 ```
 
+You can optionally select the PostgreSQL version provided by Nixpkgs:
+
+```sh
+nix run git+https://git.skreutz.com/temp-postgres.git#temp-postgres_18 -- --help
+```
+
 Try using Nix' `--refresh` flag, or adding `?ref=main&shallow=0` to the URL if you experience caching issues.
 
 See the [NixOS example](./examples/nixos) for how to install `temp-postgres` on NixOS using Nix flakes.
diff --git a/examples/nixos/flake.nix b/examples/nixos/flake.nix
index f97422c..78bc39a 100644
--- a/examples/nixos/flake.nix
+++ b/examples/nixos/flake.nix
@@ -29,7 +29,12 @@
           modules = [
             # The following goes typically into ./configuration.nix
             {
-              environment.systemPackages = [ inputs.temp-postgres.packages.${system}.default ];
+              environment.systemPackages = [
+                inputs.temp-postgres.packages.${system}.default
+
+                # Optionally select the PostgreSQL version provided by Nixpkgs.
+                #inputs.temp-postgres.packages.${system}.temp-postgres_18
+              ];
 
               users.users.stefan = {
                 isNormalUser = true;
diff --git a/flake.nix b/flake.nix
index 7b2eb9c..2076939 100644
--- a/flake.nix
+++ b/flake.nix
@@ -30,28 +30,46 @@
         let
           version = builtins.head (lib.splitString "\n" (builtins.readFile ./version));
           revision = lib.toString (self.shortRev or self.dirtyShortRev or "unknown");
+          mkPackage =
+            {
+              postgresql,
+              suffix ? "",
+            }:
+            pkgs.stdenv.mkDerivation {
+              name = "temp-postgres-${version}-${revision}${suffix}";
+              version = "${version}-${revision}";
+              src = lib.cleanSource (
+                builtins.path {
+                  path = ./.;
+                  name = "temp-postgres";
+                }
+              );
+              nativeBuildInputs = [ pkgs.makeBinaryWrapper ];
+              installPhase = ''
+                mkdir -p $out/bin
+                cp temp-postgres.sh $out/bin/temp-postgres
+                mkdir -p $out/man/man1
+                cp temp-postgres.1 $out/man/man1/temp-postgres.1
+                wrapProgram $out/bin/temp-postgres --prefix PATH : ${lib.makeBinPath [ postgresql ]}
+              '';
+            };
+          postgresqlVersions = lib.mapAttrs' (
+            name: drv:
+            let
+              postgresqlVersion = lib.removePrefix "postgresql_" name;
+            in
+            lib.nameValuePair "temp-postgres_${postgresqlVersion}" (mkPackage {
+              postgresql = drv;
+              suffix = "_${postgresqlVersion}";
+            })
+          ) pkgs.postgresqlVersions;
         in
         {
-          packages.default = self'.packages.temp-postgres;
-
-          packages.temp-postgres = pkgs.stdenv.mkDerivation {
-            name = "temp-postgres-${version}-${revision}";
-            version = "${version}-${revision}";
-            src = lib.cleanSource (
-              builtins.path {
-                path = ./.;
-                name = "temp-postgres";
-              }
-            );
-            nativeBuildInputs = [ pkgs.makeBinaryWrapper ];
-            installPhase = ''
-              mkdir -p $out/bin
-              cp temp-postgres.sh $out/bin/temp-postgres
-              mkdir -p $out/man/man1
-              cp temp-postgres.1 $out/man/man1/temp-postgres.1
-              wrapProgram $out/bin/temp-postgres --prefix PATH : ${lib.makeBinPath [ pkgs.postgresql ]}
-            '';
-          };
+          packages = {
+            default = self'.packages.temp-postgres;
+            temp-postgres = mkPackage { postgresql = pkgs.postgresql; };
+          }
+          // postgresqlVersions;
 
           formatter = pkgs.nixfmt-tree;
 
-- 
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