Switched to Redis cache in production (#761)

Gemfile

@@ -83,6 +83,10 @@ group :production do
 
   # For a better logging library in production
   gem "lograge"
+
+  # Use  for the cache store in production
+  gem 'redis'
+  gem 'hiredis'
 end
 
 # Ruby linting.

Gemfile.lock

@@ -140,6 +140,7 @@ GEM
     hashie (3.6.0)
     health_check (3.0.0)
       railties (>= 5.0)
+    hiredis (0.6.3)
     http_accept_language (2.1.1)
     i18n (1.6.0)
       concurrent-ruby (~> 1.0)
@@ -257,6 +258,7 @@ GEM
     recaptcha (5.0.0)
       json
     redcarpet (3.4.0)
+    redis (4.1.2)
     remote_syslog_logger (1.0.4)
       syslog_protocol
     request_store (1.4.1)
@@ -363,6 +365,7 @@ DEPENDENCIES
   faker
   font-awesome-sass (~> 5.9.0)
   health_check
+  hiredis
   http_accept_language
   i18n-language-mapping (~> 0.1.0)
   jbuilder (~> 2.5)
@@ -385,6 +388,7 @@ DEPENDENCIES
   random_password
   recaptcha
   redcarpet
+  redis
   remote_syslog_logger
   rspec-rails (~> 3.7)
   rubocop

config/environments/production.rb

@@ -16,7 +16,22 @@ Rails.application.configure do
   config.consider_all_requests_local       = false
   config.action_controller.perform_caching = true
 
+  if ENV['REDIS_URL'].present?
+    # Set up Redis cache store
+    config.cache_store = :redis_cache_store, { url: ENV['REDIS_URL'],
+
+      connect_timeout:    30,  # Defaults to 20 seconds
+      read_timeout:       0.2, # Defaults to 1 second
+      write_timeout:      0.2, # Defaults to 1 second
+      reconnect_attempts: 1,   # Defaults to 0
+
+      error_handler: lambda { |method:, returning:, exception:|
+        config.logger.warn "Support: Redis cache action #{method} failed and returned '#{returning}': #{exception}"
+      } }
+  else
     config.cache_store = :memory_store
+  end
+
   config.public_file_server.headers = {
     'Cache-Control' => "public, max-age=#{1.years.to_i}"
   }