From 2f363f9858d31a15196166089363c80d65ae2d7d Mon Sep 17 00:00:00 2001
From: Chris Banks <chris.banks@digital.cabinet-office.gov.uk>
Date: Thu, 8 Dec 2022 17:28:17 +0000
Subject: [PATCH 1/2] Dockerfile cleanup.

- Add .dockerignore. docker build no longer fails when there are build
  artefacts in the source directory.
- Use `$APP_HOME` from the base image instead of hardcoding `/app`
  throughout.
- Remove unnecessary and misleading definition of `PORT` env var.
- Re-enable bootsnap.
- Simplify the command, now that we no longer need to run `bundle exec`
  explicitly.
---
 .dockerignore | 14 ++++++++++++++
 Dockerfile    | 22 ++++++++++------------
 2 files changed, 24 insertions(+), 12 deletions(-)
 create mode 100644 .dockerignore

diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 000000000..80100df1e
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1,14 @@
+.dockerignore
+.git
+.gitignore
+Dockerfile
+Jenkinsfile
+Procfile
+README.md
+coverage
+docs
+features
+log
+spec
+test
+tmp
diff --git a/Dockerfile b/Dockerfile
index 42dd54b6d..7f6c9a2ad 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,24 +3,22 @@ ARG builder_image=ghcr.io/alphagov/govuk-ruby-builder:3.1.2
 
 FROM $builder_image AS builder
 
-WORKDIR /app
-
+WORKDIR $APP_HOME
 COPY Gemfile* .ruby-version ./
 RUN bundle install
-
-COPY . /app
-RUN bundle exec rails assets:precompile && rm -rf /app/log
+COPY . ./
+RUN bundle exec bootsnap precompile --gemfile .
+RUN bundle exec rails assets:precompile && rm -rf log
 
 
 FROM $base_image
 
-# TODO: remove PORT and set it in publishing-e2e-tests instead.
-ENV GOVUK_APP_NAME=government-frontend PORT=3090
+ENV GOVUK_APP_NAME=government-frontend
 
-COPY --from=builder /usr/local/bundle/ /usr/local/bundle/
-COPY --from=builder /app /app/
+WORKDIR $APP_HOME
+COPY --from=builder $BUNDLE_PATH/ $BUNDLE_PATH/
+COPY --from=builder $BOOTSNAP_CACHE_DIR/ $BOOTSNAP_CACHE_DIR/
+COPY --from=builder $APP_HOME ./
 
 USER app
-WORKDIR /app
-
-CMD ["bundle", "exec", "puma"]
+CMD ["puma"]

From c5d5971fc38788692ce290e078d6abf481ceb7cf Mon Sep 17 00:00:00 2001
From: Chris Banks <chris.banks@digital.cabinet-office.gov.uk>
Date: Thu, 8 Dec 2022 17:39:47 +0000
Subject: [PATCH 2/2] Use bootsnap to improve startup time.

---
 Gemfile        | 1 +
 Gemfile.lock   | 5 +++++
 config/boot.rb | 1 +
 3 files changed, 7 insertions(+)

diff --git a/Gemfile b/Gemfile
index 5e6fadcbd..38a19fa1a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,6 +2,7 @@ source "https://rubygems.org"
 
 gem "rails", "7.0.4"
 
+gem "bootsnap", require: false
 gem "dalli"
 gem "gds-api-adapters"
 gem "govuk_ab_testing"
diff --git a/Gemfile.lock b/Gemfile.lock
index 67174d32a..7139c0c0c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -83,6 +83,8 @@ GEM
       smart_properties
     binding_of_caller (1.0.0)
       debug_inspector (>= 0.0.1)
+    bootsnap (1.15.0)
+      msgpack (~> 1.2)
     brakeman (5.3.1)
     builder (3.2.4)
     capybara (3.38.0)
@@ -206,6 +208,8 @@ GEM
       ruby2_keywords (>= 0.0.5)
     net-imap (0.3.2)
       date
+    msgpack (1.6.0)
+    net-imap (0.3.1)
       net-protocol
     net-pop (0.1.2)
       net-protocol
@@ -395,6 +399,7 @@ PLATFORMS
 DEPENDENCIES
   better_errors
   binding_of_caller
+  bootsnap
   capybara
   climate_control
   dalli
diff --git a/config/boot.rb b/config/boot.rb
index 282011619..997563c2a 100644
--- a/config/boot.rb
+++ b/config/boot.rb
@@ -1,3 +1,4 @@
 ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../Gemfile", __dir__)
 
 require "bundler/setup" # Set up gems listed in the Gemfile.
+require "bootsnap/setup"