Migrate from thin to puma for the web server

bc-prometheus-ruby.gemspec

@@ -35,6 +35,7 @@ Gem::Specification.new do |spec|
 
   spec.add_runtime_dependency 'bigcommerce-multitrap', '~> 0.1'
   spec.add_runtime_dependency 'prometheus_exporter', '~> 0.7'
+  spec.add_runtime_dependency 'puma', '> 5'
+  spec.add_runtime_dependency 'rack', '>= 3.0'
   spec.add_runtime_dependency 'rake', '>= 10.0'
-  spec.add_runtime_dependency 'thin', '~> 1.7'
 end

lib/bigcommerce/prometheus.rb

@@ -22,7 +22,8 @@
 require 'prometheus_exporter/client'
 require 'prometheus_exporter/middleware'
 require 'prometheus_exporter/instrumentation'
-require 'thin'
+require 'puma'
+require 'rack'
 
 require_relative 'prometheus/version'
 require_relative 'prometheus/loggable'
@@ -42,14 +43,14 @@
 require_relative 'prometheus/integrations/puma'
 require_relative 'prometheus/integrations/resque'
 
-require_relative 'prometheus/servers/thin/server'
-require_relative 'prometheus/servers/thin/rack_app'
-require_relative 'prometheus/servers/thin/server_metrics'
-require_relative 'prometheus/servers/thin/controllers/base_controller'
-require_relative 'prometheus/servers/thin/controllers/error_controller'
-require_relative 'prometheus/servers/thin/controllers/metrics_controller'
-require_relative 'prometheus/servers/thin/controllers/not_found_controller'
-require_relative 'prometheus/servers/thin/controllers/send_metrics_controller'
+require_relative 'prometheus/servers/puma/server'
+require_relative 'prometheus/servers/puma/rack_app'
+require_relative 'prometheus/servers/puma/server_metrics'
+require_relative 'prometheus/servers/puma/controllers/base_controller'
+require_relative 'prometheus/servers/puma/controllers/error_controller'
+require_relative 'prometheus/servers/puma/controllers/metrics_controller'
+require_relative 'prometheus/servers/puma/controllers/not_found_controller'
+require_relative 'prometheus/servers/puma/controllers/send_metrics_controller'
 
 module Bigcommerce
   ##

lib/bigcommerce/prometheus/server.rb

@@ -35,7 +35,7 @@ def initialize(host: nil, port: nil, timeout: nil, prefix: nil, logger: nil, thr
         @prefix = (prefix || ::PrometheusExporter::DEFAULT_PREFIX).to_s
         @process_name = ::Bigcommerce::Prometheus.process_name
         @logger = logger || ::Bigcommerce::Prometheus.logger
-        @server = ::Bigcommerce::Prometheus::Servers::Thin::Server.new(
+        @server = ::Bigcommerce::Prometheus::Servers::Puma::Server.new(
           port: @port,
           timeout: @timeout,
           logger: @logger,
@@ -52,12 +52,10 @@ def initialize(host: nil, port: nil, timeout: nil, prefix: nil, logger: nil, thr
       def start
         @logger.info "[bigcommerce-prometheus][#{@process_name}] Starting prometheus exporter on port #{@host}:#{@port}"
 
-        @run_thread = ::Thread.start do
-          @server.start
-        end
+        @run_thread = @server.run
         @running = true
 
-        @logger.info "[bigcommerce-prometheus][#{@process_name}] Prometheus exporter started on #{@host}:#{@port} with #{@server.threadpool_size} threads"
+        @logger.info "[bigcommerce-prometheus][#{@process_name}] Prometheus exporter started on #{@host}:#{@port} with #{@server.max_threads} threads"
 
         @server
       rescue ::StandardError => e
@@ -81,7 +79,7 @@ def start_until_stopped
       # Stop the server
       #
       def stop
-        @server.stop!
+        @server.stop
         @run_thread.kill
         @running = false
         $stdout.puts "[bigcommerce-prometheus][#{@process_name}] Prometheus exporter cleanly shut down"

lib/bigcommerce/prometheus/servers/thin/controllers/base_controller.rb → lib/bigcommerce/prometheus/servers/puma/controllers/base_controller.rb

@@ -18,16 +18,16 @@
 module Bigcommerce
   module Prometheus
     module Servers
-      module Thin
+      module Puma
         module Controllers
           ##
-          # Base thin controller for prometheus metrics
+          # Base puma controller for prometheus metrics
           #
           class BaseController
             ##
             # @param [Rack::Request] request
             # @param [Rack::Response] response
-            # @param [Bigcommerce::Prometheus::Servers::Thin::ServerMetrics]
+            # @param [Bigcommerce::Prometheus::Servers::Puma::ServerMetrics]
             # @param [PrometheusExporter::Server::Collector] collector
             # @param [Logger] logger
             #

lib/bigcommerce/prometheus/servers/thin/controllers/error_controller.rb → lib/bigcommerce/prometheus/servers/puma/controllers/error_controller.rb

@@ -18,7 +18,7 @@
 module Bigcommerce
   module Prometheus
     module Servers
-      module Thin
+      module Puma
         module Controllers
           ##
           # Handle 500s

lib/bigcommerce/prometheus/servers/thin/controllers/metrics_controller.rb → lib/bigcommerce/prometheus/servers/puma/controllers/metrics_controller.rb

@@ -22,7 +22,7 @@
 module Bigcommerce
   module Prometheus
     module Servers
-      module Thin
+      module Puma
         module Controllers
           ##
           # GET /metrics

lib/bigcommerce/prometheus/servers/thin/controllers/not_found_controller.rb → lib/bigcommerce/prometheus/servers/puma/controllers/not_found_controller.rb

@@ -18,7 +18,7 @@
 module Bigcommerce
   module Prometheus
     module Servers
-      module Thin
+      module Puma
         module Controllers
           ##
           # Handle invalid requests to server

lib/bigcommerce/prometheus/servers/thin/controllers/send_metrics_controller.rb → lib/bigcommerce/prometheus/servers/puma/controllers/send_metrics_controller.rb

@@ -18,7 +18,7 @@
 module Bigcommerce
   module Prometheus
     module Servers
-      module Thin
+      module Puma
         module Controllers
           ##
           # POST /send-metrics

lib/bigcommerce/prometheus/servers/thin/rack_app.rb → lib/bigcommerce/prometheus/servers/puma/rack_app.rb

@@ -18,9 +18,9 @@
 module Bigcommerce
   module Prometheus
     module Servers
-      module Thin
+      module Puma
         ##
-        # Handles metrics requests as a Rack App on the Thin server
+        # Handles metrics requests as a Rack App on the Puma server
         #
         class RackApp
           ##
@@ -29,7 +29,7 @@ def initialize(collector: nil, timeout: nil, logger: nil)
             @timeout = timeout || ::Bigcommerce::Prometheus.server_timeout
             @collector = collector || ::PrometheusExporter::Server::Collector.new
             @logger = logger || ::Bigcommerce::Prometheus.logger
-            @server_metrics = ::Bigcommerce::Prometheus::Servers::Thin::ServerMetrics.new(logger: @logger)
+            @server_metrics = ::Bigcommerce::Prometheus::Servers::Puma::ServerMetrics.new(logger: @logger)
           end
 
           def call(env)
@@ -39,7 +39,7 @@ def call(env)
             handle(controller: controller, request: request, response: response)
           rescue StandardError => e
             @logger.error "Error: #{e.message}"
-            handle(controller: ::Bigcommerce::Prometheus::Servers::Thin::Controllers::ErrorController, request: request, response: response)
+            handle(controller: ::Bigcommerce::Prometheus::Servers::Puma::Controllers::ErrorController, request: request, response: response)
           end
 
           ##
@@ -60,11 +60,11 @@ def add_type_collector(collector)
           #
           def route(request)
             if request.fullpath == '/metrics' && request.request_method.to_s.downcase == 'get'
-              Bigcommerce::Prometheus::Servers::Thin::Controllers::MetricsController
+              Bigcommerce::Prometheus::Servers::Puma::Controllers::MetricsController
             elsif request.fullpath == '/send-metrics' && request.request_method.to_s.downcase == 'post'
-              Bigcommerce::Prometheus::Servers::Thin::Controllers::SendMetricsController
+              Bigcommerce::Prometheus::Servers::Puma::Controllers::SendMetricsController
             else
-              Bigcommerce::Prometheus::Servers::Thin::Controllers::NotFoundController
+              Bigcommerce::Prometheus::Servers::Puma::Controllers::NotFoundController
             end
           end
 

lib/bigcommerce/prometheus/servers/thin/server.rb → lib/bigcommerce/prometheus/servers/puma/server.rb

@@ -18,21 +18,21 @@
 module Bigcommerce
   module Prometheus
     module Servers
-      module Thin
+      module Puma
         ##
-        # Thin adapter for server
+        # Puma adapter for server
         #
-        class Server < ::Thin::Server
+        class Server < ::Puma::Server
           def initialize(port: nil, host: nil, timeout: nil, logger: nil, thread_pool_size: nil)
             @port = port || ::Bigcommerce::Prometheus.server_port
             @host = host || ::Bigcommerce::Prometheus.server_host
             @timeout = timeout || ::Bigcommerce::Prometheus.server_timeout
             @logger = logger || ::Bigcommerce::Prometheus.logger
-            @rack_app = ::Bigcommerce::Prometheus::Servers::Thin::RackApp.new(timeout: timeout, logger: logger)
-            super(@host, @port, @rack_app)
-            ::Thin::Logging.logger = @logger
+            @rack_app = ::Bigcommerce::Prometheus::Servers::Puma::RackApp.new(timeout: timeout, logger: logger)
+            thread_pool_size = (thread_pool_size || ::Bigcommerce::Prometheus.server_thread_pool_size).to_i
+            super(@rack_app, nil, max_threads: thread_pool_size)
+            add_tcp_listener(@host, @port)
             @logger.info "[bigcommerce-prometheus] Prometheus server started on #{@host}:#{@port}"
-            self.threadpool_size = (thread_pool_size || ::Bigcommerce::Prometheus.server_thread_pool_size).to_i
           end
 
           ##

lib/bigcommerce/prometheus/servers/thin/server_metrics.rb → lib/bigcommerce/prometheus/servers/puma/server_metrics.rb

@@ -22,7 +22,7 @@
 module Bigcommerce
   module Prometheus
     module Servers
-      module Thin
+      module Puma
         ##
         # Server metrics for the collector
         #

spec/bigcommerce/prometheus/servers/thin/controllers/metrics_controller_spec.rb → spec/bigcommerce/prometheus/servers/puma/controllers/metrics_controller_spec.rb

@@ -15,7 +15,7 @@
 #
 require 'spec_helper'
 
-describe Bigcommerce::Prometheus::Servers::Thin::Controllers::MetricsController do
+describe Bigcommerce::Prometheus::Servers::Puma::Controllers::MetricsController do
   let(:request_method) { 'GET' }
   let(:env) do
     {
@@ -27,7 +27,7 @@
   let(:request) { Rack::Request.new(env) }
   let(:response) { Rack::Response.new }
   let(:collector) { PrometheusExporter::Server::Collector.new }
-  let(:server_metrics) { Bigcommerce::Prometheus::Servers::Thin::ServerMetrics.new }
+  let(:server_metrics) { Bigcommerce::Prometheus::Servers::Puma::ServerMetrics.new }
   let(:controller) { described_class.new(request: request, response: response, server_metrics: server_metrics, collector: collector, logger: logger) }
 
   let(:metrics) { ['ruby_collector_metrics_total 19', 'ruby_collector_sessions_total 19'].join("\n") }

spec/bigcommerce/prometheus/servers/thin/controllers/send_metrics_controller_spec.rb → spec/bigcommerce/prometheus/servers/puma/controllers/send_metrics_controller_spec.rb

@@ -15,7 +15,7 @@
 #
 require 'spec_helper'
 
-describe Bigcommerce::Prometheus::Servers::Thin::Controllers::SendMetricsController do
+describe Bigcommerce::Prometheus::Servers::Puma::Controllers::SendMetricsController do
   let(:request_method) { 'POST' }
   let(:env) do
     {
@@ -27,7 +27,7 @@
   let(:request) { Rack::Request.new(env) }
   let(:response) { Rack::Response.new }
   let(:collector) { PrometheusExporter::Server::Collector.new }
-  let(:server_metrics) { Bigcommerce::Prometheus::Servers::Thin::ServerMetrics.new }
+  let(:server_metrics) { Bigcommerce::Prometheus::Servers::Puma::ServerMetrics.new }
   let(:controller) { described_class.new(request: request, response: response, server_metrics: server_metrics, collector: collector, logger: logger) }
 
   describe '#call' do

spec/bigcommerce/prometheus/servers/puma/server_spec.rb

@@ -0,0 +1,51 @@
+require 'spec_helper'
+
+describe Bigcommerce::Prometheus::Servers::Puma::Server do
+  let(:server) { described_class.new(port: default_port) }
+  let(:default_port) { 9800 + rand(100) }
+  before do
+    Bigcommerce::Prometheus.reset
+  end
+
+  context 'when the server is initialized' do
+    it 'has a valid rack app' do
+      expect(server.app).to be_a(Bigcommerce::Prometheus::Servers::Puma::RackApp)
+    end
+  end
+
+  context 'when the thread pool size is not configured' do
+    it 'falls back to the default configuration' do
+      expect(server.max_threads).to eq ::Bigcommerce::Prometheus.server_thread_pool_size
+      expect(server.max_threads).to eq 3
+    end
+  end
+
+  context 'when the default thread pool size is configured' do
+    let(:server_thread_pool_size) { 12 }
+
+    before do
+      Bigcommerce::Prometheus.configure do |c|
+        c.server_thread_pool_size = server_thread_pool_size
+      end
+    end
+
+    it 'allows you to set the thread pool size through the configuration block' do
+      expect(server.max_threads).to eq server_thread_pool_size
+    end
+  end
+
+  context 'when the default port is configured' do
+    let(:server_port) { 9000 + rand(100) }
+    let(:default_port) { nil }
+
+    before do
+      Bigcommerce::Prometheus.configure do |c|
+        c.server_port = server_port
+      end
+    end
+
+    it 'allows you to set the port through the configuration block' do
+      expect(server.connected_ports).to include server_port
+    end
+  end
+end