From 95a6a3eaa221e2bd56d010c7d06c0aead58b24e7 Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Fri, 23 Oct 2026 20:06:19 -0400
Subject: [PATCH] Separate out the install of dependencies so they can  be
 cached as docker layers before the homepage source code is copied in.

---
 docker/server/Dockerfile | 6 +++++-
 flake.nix                | 9 ++++++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/docker/server/Dockerfile b/docker/server/Dockerfile
index d767bc1..7b1fa45 100644
--- a/docker/server/Dockerfile
+++ b/docker/server/Dockerfile
@@ -15,9 +15,13 @@ EOF
 
 RUN cp "$(nix build nixpkgs#cacert --print-out-paths)/etc/ssl/certs/ca-bundle.crt" /tmp/ca-bundle.crt
 
-COPY . /tmp/build
+COPY flake.nix flake.lock /tmp/build
 WORKDIR /tmp/build
 
+RUN --mount=type=ssh GIT_SSH_COMMAND="ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null" nix build --no-link '.#dependencies'
+
+COPY . /tmp/build
+
 RUN --mount=type=ssh GIT_SSH_COMMAND="ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null" nix build '.#docker_env'
 
 # Export the built closure to a folder
diff --git a/flake.nix b/flake.nix
index 97e4696..1165a71 100644
--- a/flake.nix
+++ b/flake.nix
@@ -74,6 +74,11 @@
           inherit (appliedOverlay.homepage)
             release
             ;
+          dependencies = pkgs.symlinkJoin {
+            # This is to enable the docker image to install all the dependencies, cache that layer, and then build the final site after the org source files have been loaded. Without this, every update to the blog posts would result in recompiling everything.
+            name = "homepage-dependencies";
+            paths = appliedOverlay.homepage.dependencies;
+          };
           docker_env = pkgs.stdenv.mkDerivation {
             pname = "homepage-docker-env";
             version = "0.0.0";
@@ -100,14 +105,16 @@
             natter' = (natter.overlays.default final final).natter.release;
             organic_ast_explorer' =
               (organic_ast_explorer.overlays.default final final).organic_ast_explorer.release;
-            release = homepageScope.callPackage ./nix/package.nix {
+            dependencies = {
               natter = natter';
               organic_ast_explorer = organic_ast_explorer';
               inherit homepage_private;
             };
+            release = homepageScope.callPackage ./nix/package.nix dependencies;
           in
           {
             inherit release;
+            dependencies = (builtins.attrValues dependencies);
           }
         );
       };