From 51ab69a2cf41627068aa0067390623d5c0625232 Mon Sep 17 00:00:00 2001
From: Mike Dalessio <mike@37signals.com>
Date: Mon, 11 Aug 2025 14:00:00 -0400
Subject: [PATCH] Dockerfile: Use a cache mount for bundled gems

ref: https://fizzy.37signals.com/5986089/collections/7/cards/1338
---
 Dockerfile | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 0faa475f7..996e9aa4b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -24,9 +24,8 @@ RUN apt-get update -qq && \
 
 # Install application gems
 COPY Gemfile Gemfile.lock .ruby-version ./
-RUN --mount=type=secret,id=GITHUB_TOKEN \
-    gem install bundler &&\
-    BUNDLE_GITHUB__COM="$(cat /run/secrets/GITHUB_TOKEN):x-oauth-basic" bundle install && \
+RUN --mount=type=secret,id=GITHUB_TOKEN --mount=type=cache,id=fizzy-permabundle-${RUBY_VERSION},sharing=locked,target=/permabundle \
+    BUNDLE_PATH=/permabundle BUNDLE_GITHUB__COM="$(cat /run/secrets/GITHUB_TOKEN):x-oauth-basic" bundle install && \
     rm -rf ~/.bundle/ "${BUNDLE_PATH}"/ruby/*/cache "${BUNDLE_PATH}"/ruby/*/bundler/gems/*/.git && \
     bundle exec bootsnap precompile --gemfile