Add healthcheck endpoint for web (#11770)

Gemfile

@@ -50,6 +50,7 @@ gem 'fastimage'
 gem 'goldfinger', '~> 2.1'
 gem 'hiredis', '~> 0.6'
 gem 'redis-namespace', '~> 1.5'
+gem 'health_check', '~> 3.0'
 gem 'htmlentities', '~> 4.3'
 gem 'http', '~> 3.3'
 gem 'http_accept_language', '~> 2.1'

Gemfile.lock

@@ -278,6 +278,8 @@ GEM
       concurrent-ruby (~> 1.0)
     hashdiff (1.0.0)
     hashie (3.6.0)
+    health_check (3.0.0)
+      railties (>= 5.0)
     heapy (0.1.4)
     highline (2.0.1)
     hiredis (0.6.3)
@@ -706,6 +708,7 @@ DEPENDENCIES
   fuubar (~> 2.4)
   goldfinger (~> 2.1)
   hamlit-rails (~> 0.2)
+  health_check (~> 3.0)
   hiredis (~> 0.6)
   htmlentities (~> 4.3)
   http (~> 3.3)

app/controllers/application_controller.rb

@@ -41,7 +41,7 @@ class ApplicationController < ActionController::Base
   private
 
   def https_enabled?
-    Rails.env.production?
+    Rails.env.production? && !request.path.start_with?('/health')
   end
 
   def authorized_fetch_mode?

config/initializers/health_check.rb

@@ -0,0 +1,6 @@
+HealthCheck.setup do |config|
+  config.uri = 'health'
+
+  config.standard_checks = %w(database migrations cache)
+  config.full_checks = %w(database migrations cache)
+end

config/routes.rb

@@ -10,6 +10,8 @@ Rails.application.routes.draw do
 
   mount LetterOpenerWeb::Engine, at: 'letter_opener' if Rails.env.development?
 
+  health_check_routes
+
   authenticate :user, lambda { |u| u.admin? } do
     mount Sidekiq::Web, at: 'sidekiq', as: :sidekiq
     mount PgHero::Engine, at: 'pghero', as: :pghero

docker-compose.yml

@@ -43,7 +43,7 @@ services:
       - external_network
       - internal_network
     healthcheck:
-      test: ["CMD-SHELL", "wget -q --spider --header 'x-forwarded-proto: https' --proxy=off localhost:3000/api/v1/instance || exit 1"]
+      test: ["CMD-SHELL", "wget -q --spider --proxy=off localhost:3000/health || exit 1"]
     ports:
       - "127.0.0.1:3000:3000"
     depends_on:
@@ -63,7 +63,7 @@ services:
       - external_network
       - internal_network
     healthcheck:
-      test: ["CMD-SHELL", "wget -q --spider --header 'x-forwarded-proto: https' --proxy=off localhost:4000/api/v1/streaming/health || exit 1"]
+      test: ["CMD-SHELL", "wget -q --spider --proxy=off localhost:4000/api/v1/streaming/health || exit 1"]
     ports:
       - "127.0.0.1:4000:4000"
     depends_on: