WIP: Replace Thin with Puma

Gemfile

@@ -39,7 +39,7 @@ gem 'sinatra-contrib'
 gem 'statsd-ruby', '~> 1.4.0'
 gem 'steno'
 gem 'talentbox-delayed_job_sequel', '~> 4.3.0'
-gem 'thin'
+gem 'puma'
 gem 'unf'
 gem 'vmstat', '~> 2.3'
 gem 'yajl-ruby'

Gemfile.lock

@@ -123,7 +123,6 @@ GEM
     crack (0.4.3)
       safe_yaml (~> 1.0.0)
     crass (1.0.6)
-    daemons (1.2.6)
     debase (0.2.5.beta2)
       debase-ruby_core_source (>= 0.10.12)
     debase-ruby_core_source (0.10.12)
@@ -306,6 +305,7 @@ GEM
     netaddr (2.0.4)
     netrc (0.11.0)
     newrelic_rpm (6.15.0)
+    nio4r (2.5.7)
     nokogiri (1.11.3)
       mini_portile2 (~> 2.5.0)
       racc (~> 1.4)
@@ -334,6 +334,8 @@ GEM
       byebug (~> 11.0)
       pry (~> 0.13.0)
     public_suffix (4.0.6)
+    puma (5.2.2)
+      nio4r (~> 2.0)
     racc (1.5.2)
     rack (2.2.3)
     rack-protection (2.0.8.1)
@@ -480,10 +482,6 @@ GEM
       delayed_job (~> 4.1.0)
       sequel (>= 3.38, < 6.0)
       tzinfo
-    thin (1.7.2)
-      daemons (~> 1.0, >= 1.0.9)
-      eventmachine (~> 1.0, >= 1.0.4)
-      rack (>= 1, < 3)
     thor (1.1.0)
     thread_safe (0.3.6)
     tilt (2.0.10)
@@ -569,6 +567,7 @@ DEPENDENCIES
   protobuf (= 3.6.12)
   pry-byebug
   public_suffix
+  puma
   rack-test
   railties (~> 5.2.4, >= 5.2.4.3)
   rake
@@ -596,7 +595,6 @@ DEPENDENCIES
   statsd-ruby (~> 1.4.0)
   steno
   talentbox-delayed_job_sequel (~> 4.3.0)
-  thin
   timecop
   unf
   vcap-concurrency!

lib/cloud_controller.rb

@@ -1,8 +1,9 @@
 require 'sinatra'
 require 'sequel'
-require 'thin'
 require 'multi_json'
 require 'delayed_job'
+require 'puma'
+require 'puma/configuration'
 
 require 'allowy'
 

lib/cloud_controller/config_schemas/base/api_schema.rb

@@ -237,7 +237,14 @@ class ApiSchema < VCAP::Config
             },
 
             request_timeout_in_seconds: Integer,
-            threadpool_size: Integer,
+            optional(:puma) => {
+              workers: Integer,
+              optional(:threads) => {
+                min: Integer,
+                max: Integer
+              }
+            },
+
             skip_cert_verify: bool,
 
             install_buildpacks: [

lib/cloud_controller/db.rb

@@ -54,6 +54,7 @@ def self.load_models(db_config, logger)
 
       require 'models'
       require 'delayed_job_sequel'
+      db
     end
 
     def self.load_models_without_migrations_check(db_config, logger)

lib/cloud_controller/runner.rb

@@ -73,59 +73,30 @@ def parse_config(secrets_hash)
 
     def run!
       create_pidfile
+      start_cloud_controller
 
-      EM.run do
-        start_cloud_controller
+      request_metrics = VCAP::CloudController::Metrics::RequestMetrics.new(statsd_client)
+      builder = RackAppBuilder.new
+      app = builder.build(@config, request_metrics)
 
-        request_metrics = VCAP::CloudController::Metrics::RequestMetrics.new(statsd_client)
-        gather_periodic_metrics
-
-        builder = RackAppBuilder.new
-        app     = builder.build(@config, request_metrics)
-
-        start_thin_server(app)
-      rescue => e
-        logger.error "Encountered error: #{e}\n#{e.backtrace.join("\n")}"
-        raise e
-      end
+      start_puma_server app
+    rescue => e
+      logger.error "Encountered error: #{e}\n#{e.backtrace.join("\n")}"
+      raise e
     end
 
     def gather_periodic_metrics
       logger.info('starting periodic metrics updater')
       periodic_updater.setup_updates
     end
 
-    def trap_signals
-      %w(TERM INT QUIT).each do |signal|
-        trap(signal) do
-          EM.add_timer(0) do
-            logger.warn("Caught signal #{signal}")
-            stop!
-          end
-        end
-      end
-
-      trap('USR1') do
-        EM.add_timer(0) do
-          logger.warn('Collecting diagnostics')
-          collect_diagnostics
-        end
-      end
-    end
-
-    def stop!
-      stop_thin_server
-      logger.info('Stopping EventMachine')
-      EM.stop
-    end
-
     private
 
     def start_cloud_controller
       setup_logging
       setup_telemetry_logging
-      setup_db
       setup_blobstore
+      @db = setup_db
       @config.configure_components
 
       setup_app_log_emitter
@@ -186,28 +157,31 @@ def fluent_emitter
       ))
     end
 
-    def start_thin_server(app)
-      @thin_server = if @config.get(:nginx, :use_nginx)
-                       Thin::Server.new(@config.get(:nginx, :instance_socket), signals: false)
-                     else
-                       Thin::Server.new(@config.get(:external_host), @config.get(:external_port), signals: false)
-                     end
-
-      @thin_server.app = app
-      trap_signals
-
-      # The routers proxying to us handle killing inactive connections.
-      # Set an upper limit just to be safe.
-      @thin_server.timeout = @config.get(:request_timeout_in_seconds)
-      @thin_server.threaded = true
-      @thin_server.threadpool_size = @config.get(:threadpool_size)
-      logger.info("Starting thin server with #{EventMachine.threadpool_size} threads")
-      @thin_server.start!
-    end
-
-    def stop_thin_server
-      logger.info('Stopping Thin Server.')
-      @thin_server.stop if @thin_server
+    def start_puma_server(app)
+      puma_config = Puma::Configuration.new do |user_config|
+        user_config.workers(@config.get(:puma, :workers) || 3)
+        user_config.threads(@config.get(:puma, :threads, :min) || 0, @config.get(:puma, :threads, :max) || 5)
+        bind_address = if @config.get(:nginx, :use_nginx)
+                         "tcp://127.0.0.1:#{@config.get(:nginx, :instance_socket)}"
+                       else
+                         "tcp://#{@config.get(:external_host)}:#{@config.get(:external_port)}"
+                       end
+        user_config.bind bind_address
+        user_config.app app
+        user_config.preload_app!
+        user_config.before_fork {
+          @db.disconnect
+        }
+        user_config.after_worker_boot {
+          Thread.new do
+            EM.run do
+              gather_periodic_metrics
+            end
+          end
+        }
+      end
+      @puma_launcher = Puma::Launcher.new(puma_config)
+      @puma_launcher.run
     end
 
     def periodic_updater