1 files changed, 31 insertions, 0 deletions
diff --git a/nix/pkgs.nix b/nix/pkgs.nix
new file mode 100644
index 0000000..cd15894
--- /dev/null
+++ b/nix/pkgs.nix
@@ -0,0 +1,31 @@
+{
+  system ? builtins.currentSystem,
+  nixpkgs ? builtins.fetchTarball {
+    url = "https://github.com/NixOS/nixpkgs/archive/22.11.tar.gz";
+    sha256 = "11w3wn2yjhaa5pv20gbfbirvjq6i3m7pqrq2msf0g7cv44vijwgw";
+  }
+}:
+let
+  # use the first version in the list for each component
+  getMajorVersion = builtins.getEnv "PPQ_POSTGRES_VERSION";
+
+  overlay = self: super: {
+    # NOTE: Overlaying `postgresql` is not possible anymore, leads to
+    # error: infinite recursion encountered
+    #
+    # TODO: Make extension packages more easily configurable.  For now
+    # just load whatever we've ever needed.
+    ppq_postgresql = super."postgresql_${getMajorVersion}".withPackages (p: [
+      p.postgis
+    ]);
+  };
+
+  pkgs =
+  import nixpkgs {
+    inherit system;
+    overlays = [
+      overlay
+    ];
+  };
+in
+pkgs