Merge pull request #9 from pedelman/configurable-server-threadpool

Adds ability to configure the server threadpool size

Author: pedelman

CHANGELOG.md

@@ -2,6 +2,7 @@ Changelog for the bc-prometheus-ruby gem.
 
 ### Pending Release
 
+- Add configuration to control Thin web server thread pool size. Note that the default number of threads is changing from 20 to 3. You can configure this using an environment variable or initializer.
 - Update rubocop to 1.0
 
 ### 0.3.1

README.md

@@ -39,15 +39,16 @@ Bigcommerce::Prometheus::Instrumentors::Resque.new(app: Rails.application).start
 
 After requiring the main file, you can further configure with:
 
-| Option | Description | Default |
-| ------ | ----------- | ------- |
-| client_custom_labels | A hash of custom labels to send with each client request | `{}` |
-| client_max_queue_size | The max amount of metrics to send before flushing | 10000 |
-| client_thread_sleep | How often to sleep the worker thread that manages the client buffer (seconds) | 0.5 |
-| puma_collection_frequency | How often to poll puma collection metrics (seconds) | 30 |
-| server_host | The host to run the exporter on | 0.0.0.0 |
-| server_port | The port to run the exporter on | 9394 |
-| process_name | What the current process name is. Used in logging. | `ENV['PROCESS']` | 
+| Option | Description | Default | Environment Variable |
+| ------ | ----------- | ------- | -------------------- |
+| client_custom_labels | A hash of custom labels to send with each client request | `{}` | None |
+| client_max_queue_size | The max amount of metrics to send before flushing | `10000` | `ENV['PROMETHEUS_CLIENT_MAX_QUEUE_SIZE']` |
+| client_thread_sleep | How often to sleep the worker thread that manages the client buffer (seconds) | `0.5` | `ENV['PROMETHEUS_CLIENT_THREAD_SLEEP']` |
+| puma_collection_frequency | How often to poll puma collection metrics (seconds) | `30` | `ENV['PROMETHEUS_PUMA_COLLECTION_FREQUENCY']` |
+| server_host | The host to run the exporter on | `"0.0.0.0"` | `ENV['PROMETHEUS_SERVER_HOST']` |
+| server_port | The port to run the exporter on | `9394` | `ENV['PROMETHEUS_SERVER_PORT']` |
+| server_thread_pool_size | The number of threads used for the exporter server | `3` | `ENV['PROMETHEUS_SERVER_THREAD_POOL_SIZE']` |
+| process_name | What the current process name is (used in logging) | `"unknown"` | `ENV['PROCESS']` |
 
 ## Custom Collectors
 

lib/bigcommerce/prometheus/configuration.rb

@@ -42,6 +42,7 @@ module Configuration
         server_port: ENV.fetch('PROMETHEUS_SERVER_PORT', PrometheusExporter::DEFAULT_PORT).to_i,
         server_timeout: ENV.fetch('PROMETHEUS_DEFAULT_TIMEOUT', PrometheusExporter::DEFAULT_TIMEOUT).to_i,
         server_prefix: ENV.fetch('PROMETHEUS_DEFAULT_PREFIX', PrometheusExporter::DEFAULT_PREFIX).to_s,
+        server_thread_pool_size: ENV.fetch('PROMETHEUS_SERVER_THREAD_POOL_SIZE', 3).to_i,
 
         # Custom collector configuration
         collector_collection_frequency: ENV.fetch('PROMETHEUS_DEFAULT_COLLECTOR_COLLECTION_FREQUENCY_SEC', 15).to_i,

lib/bigcommerce/prometheus/server.rb

@@ -26,15 +26,21 @@ class Server
       # @param [Integer] port
       # @param [Integer] timeout
       # @param [String] prefix
+      # @param [Integer] thread_pool_size
       #
-      def initialize(host: nil, port: nil, timeout: nil, prefix: nil, logger: nil)
+      def initialize(host: nil, port: nil, timeout: nil, prefix: nil, logger: nil, thread_pool_size: nil)
         @host = host || ::Bigcommerce::Prometheus.server_host
         @port = (port || ::Bigcommerce::Prometheus.server_port).to_i
         @timeout = (timeout || ::Bigcommerce::Prometheus.server_timeout).to_i
         @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(port: @port, timeout: @timeout, logger: @logger)
+        @server = ::Bigcommerce::Prometheus::Servers::Thin::Server.new(
+          port: @port,
+          timeout: @timeout,
+          logger: @logger,
+          thread_pool_size: (thread_pool_size || ::Bigcommerce::Prometheus.server_thread_pool_size).to_i
+        )
         @running = false
         ::PrometheusExporter::Metric::Base.default_prefix = @prefix
         setup_signal_handlers
@@ -51,7 +57,7 @@ def start
         end
         @running = true
 
-        @logger.info "[bigcommerce-prometheus][#{@process_name}] Prometheus exporter started on #{@host}:#{@port}"
+        @logger.info "[bigcommerce-prometheus][#{@process_name}] Prometheus exporter started on #{@host}:#{@port} with #{@server.threadpool_size} threads"
 
         @server
       rescue ::StandardError => e

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

@@ -25,6 +25,7 @@ module Controllers
           #
           class SendMetricsController < BaseController
             class BadMetricsError < StandardError; end
+
             class InvalidRequestError < StandardError; end
 
             ##

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

@@ -23,14 +23,15 @@ module Thin
         # Thin adapter for server
         #
         class Server < ::Thin::Server
-          def initialize(port:, host: nil, timeout: nil, logger: nil)
+          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
+            self.threadpool_size = (thread_pool_size || ::Bigcommerce::Prometheus.server_thread_pool_size).to_i
           end
 
           ##

lib/bigcommerce/prometheus/version.rb

@@ -17,6 +17,6 @@
 #
 module Bigcommerce
   module Prometheus
-    VERSION = '0.3.2.pre'
+    VERSION = '0.4.0.pre'
   end
 end

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

@@ -0,0 +1,30 @@
+require 'spec_helper'
+
+describe Bigcommerce::Prometheus::Servers::Thin::Server do
+  let(:server) { described_class.new }
+
+  before do
+    Bigcommerce::Prometheus.reset
+  end
+
+  context 'when the thread pool size is not configured' do
+    it 'falls back to the default configuration' do
+      expect(server.threadpool_size).to eq ::Bigcommerce::Prometheus.server_thread_pool_size
+      expect(server.threadpool_size).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.threadpool_size).to eq server_thread_pool_size
+    end
+  end
+end