persist mockup variants on fly volume across deploys

Source mockup WebPs are copied from the release to /data/mockups/
on startup, and variants are generated there. This eliminates the
182-job storm on every deploy that was saturating the CPU and
causing SQLite locking. After the first successful run, subsequent
deploys find all variants intact.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

config/prod.exs

@@ -19,8 +19,9 @@ config :logger, level: :info
 # Structured JSON logs for production (machine-parseable by fly logs, journalctl, Loki, etc.)
 config :logger, :default_handler, formatter: {LoggerJSON.Formatters.Basic, []}
 
-# Persistent image cache on the Fly volume (survives deploys)
+# Persistent image cache and mockup variants on the Fly volume (survives deploys)
 config :berrypod, :image_cache_dir, "/data/image_cache"
+config :berrypod, :mockup_dir, "/data/mockups"
 
 # Runtime production configuration, including reading
 # of environment variables, is done on config/runtime.exs.

lib/berrypod/images/variant_cache.ex

@@ -19,7 +19,13 @@ defmodule Berrypod.Images.VariantCache do
   alias Berrypod.Sync.ImageDownloadWorker
   import Ecto.Query
 
-  defp mockup_dir, do: Application.app_dir(:berrypod, "priv/static/mockups")
+  # Source mockups bundled in the release
+  defp release_mockup_dir, do: Application.app_dir(:berrypod, "priv/static/mockups")
+
+  # Where mockup variants live — persistent volume in prod, release dir in dev
+  defp mockup_dir do
+    Application.get_env(:berrypod, :mockup_dir) || release_mockup_dir()
+  end
 
   def start_link(opts) do
     GenServer.start_link(__MODULE__, opts, name: __MODULE__)
@@ -84,9 +90,25 @@ defmodule Berrypod.Images.VariantCache do
   end
 
   defp ensure_mockup_variants do
-    if File.dir?(mockup_dir()) do
+    output = mockup_dir()
+    release = release_mockup_dir()
+
+    # When using a persistent volume, copy source WebPs from the release
+    # so variants can be generated there (and survive deploys).
+    if output != release and File.dir?(release) do
+      File.mkdir_p!(output)
+
+      Path.wildcard(Path.join(release, "*.webp"))
+      |> Enum.reject(&is_variant?/1)
+      |> Enum.each(fn src ->
+        dest = Path.join(output, Path.basename(src))
+        unless File.exists?(dest), do: File.cp!(src, dest)
+      end)
+    end
+
+    if File.dir?(output) do
       sources =
-        Path.wildcard(Path.join(mockup_dir(), "*.webp"))
+        Path.wildcard(Path.join(output, "*.webp"))
         |> Enum.reject(&is_variant?/1)
 
       missing = Enum.reject(sources, &mockup_variants_exist?/1)

lib/berrypod_web/endpoint.ex

@@ -16,7 +16,7 @@ defmodule BerrypodWeb.Endpoint do
     websocket: [connect_info: [session: @session_options]],
     longpoll: [connect_info: [session: @session_options]]
 
-  # In prod, image variants live on the persistent volume (/data/image_cache)
+  # In prod, image variants and mockups live on the persistent volume
   # rather than inside the ephemeral release directory.
   if image_cache_dir = Application.compile_env(:berrypod, :image_cache_dir) do
     plug Plug.Static,
@@ -25,6 +25,13 @@ defmodule BerrypodWeb.Endpoint do
       cache_control_for_etags: "public, max-age=31536000, immutable"
   end
 
+  if mockup_dir = Application.compile_env(:berrypod, :mockup_dir) do
+    plug Plug.Static,
+      at: "/mockups",
+      from: mockup_dir,
+      cache_control_for_etags: "public, max-age=31536000, immutable"
+  end
+
   # Serve at "/" the static files from "priv/static" directory.
   # gzip only in prod — avoids stale .gz files from mix assets.deploy
   # shadowing freshly-built dev assets.

lib/berrypod_web/plugs/broken_url_tracker.ex

@@ -35,6 +35,7 @@ defmodule BerrypodWeb.Plugs.BrokenUrlTracker do
     String.starts_with?(path, "/assets/") or
       String.starts_with?(path, "/images/") or
       String.starts_with?(path, "/image_cache/") or
+      String.starts_with?(path, "/mockups/") or
       String.starts_with?(path, "/favicon")
   end
 end