Replace statsd-client with dogstatsd-ruby

statsd-ruby has not been released in 5+ years and the repo is archived.
dogstatsd-ruby is well maintained and gets regular releases.

Author: johha

Gemfile

@@ -6,6 +6,7 @@ gem 'clockwork', require: false
 gem 'cloudfront-signer'
 gem 'concurrent-ruby'
 gem 'digest-xxhash'
+gem 'dogstatsd-ruby', '~> 5.7'
 gem 'fluent-logger'
 gem 'googleapis-common-protos', '>= 1.8.0'
 gem 'hashdiff'
@@ -29,7 +30,6 @@ gem 'sequel', '~> 5.106'
 gem 'sequel_pg', require: 'sequel'
 gem 'sinatra', '~> 4.2'
 gem 'sinatra-contrib'
-gem 'statsd-ruby', '~> 1.5.0'
 gem 'talentbox-delayed_job_sequel', '~> 4.4.0'
 gem 'uri', '~> 1.1'
 gem 'vmstat', '~> 2.3'

Gemfile.lock

@@ -77,6 +77,7 @@ GEM
     diff-lcs (1.6.2)
     digest-xxhash (0.2.9)
     docile (1.1.5)
+    dogstatsd-ruby (5.7.1)
     drb (2.2.3)
     erb (6.0.4)
     erubi (1.13.1)
@@ -431,7 +432,6 @@ GEM
     spring (4.7.0)
     spring-commands-rspec (1.0.4)
       spring (>= 0.9.1)
-    statsd-ruby (1.5.0)
     stringio (3.2.0)
     talentbox-delayed_job_sequel (4.4.0)
       delayed_job (~> 4.1)
@@ -479,6 +479,7 @@ DEPENDENCIES
   concurrent-ruby
   debug (~> 1.11)
   digest-xxhash
+  dogstatsd-ruby (~> 5.7)
   factory_bot (~> 6.5)
   fluent-logger
   fog-aws
@@ -532,7 +533,6 @@ DEPENDENCIES
   solargraph
   spring
   spring-commands-rspec
-  statsd-ruby (~> 1.5.0)
   talentbox-delayed_job_sequel (~> 4.4.0)
   timecop
   uri (~> 1.1)

app/jobs/diego/sync.rb

@@ -1,6 +1,6 @@
 require 'cloud_controller/diego/processes_sync'
 require 'cloud_controller/diego/tasks_sync'
-require 'statsd'
+require 'cloud_controller/metrics/statsd_client_adapter'
 
 module VCAP::CloudController
   module Jobs

lib/cloud_controller/dependency_locator.rb

@@ -24,6 +24,7 @@
 require 'cloud_controller/packager/local_bits_packer'
 require 'credhub/client'
 require 'cloud_controller/metrics/prometheus_updater'
+require 'cloud_controller/metrics/statsd_client_adapter'
 require 'cloud_controller/execution_context'
 
 module CloudController
@@ -367,8 +368,8 @@ def statsd_client
       if @dependencies[:statsd_client]
         @dependencies[:statsd_client]
       elsif config.get(:enable_statsd_metrics) == true || config.get(:enable_statsd_metrics).nil?
-        Statsd.logger = Steno.logger('statsd.client')
-        register(:statsd_client, Statsd.new(config.get(:statsd_host), config.get(:statsd_port)))
+        statsd = Datadog::Statsd.new(config.get(:statsd_host), config.get(:statsd_port))
+        register(:statsd_client, VCAP::CloudController::Metrics::StatsdClientAdapter.new(statsd))
       else
         register(:statsd_client, NullStatsdClient.new)
       end
@@ -472,6 +473,10 @@ def increment(_key)
       # Null implementation
     end
 
+    def decrement(_key)
+      # Null implementation
+    end
+
     def gauge(_stat, _value, _sample_rate=1)
       # Null implementation
     end

lib/cloud_controller/metrics/request_metrics.rb

@@ -1,4 +1,4 @@
-require 'statsd'
+require 'cloud_controller/metrics/statsd_client_adapter'
 
 module VCAP::CloudController
   module Metrics

lib/cloud_controller/metrics/statsd_client_adapter.rb

@@ -0,0 +1,24 @@
+require 'datadog/statsd'
+require 'forwardable'
+
+module VCAP::CloudController::Metrics
+  # Adapts a Datadog::Statsd (dogstatsd-ruby v5) client to the small surface that
+  # StatsdUpdater relies on. dogstatsd-ruby dropped the block-yielding `batch` method
+  # that statsd-ruby offered; v5 buffers metrics internally instead. This adapter
+  # restores `batch` by yielding itself and flushing synchronously afterwards, so the
+  # emitted wire format and grouping behaviour stay unchanged.
+  class StatsdClientAdapter
+    extend Forwardable
+
+    def_delegators :@statsd, :gauge, :increment, :decrement, :timing
+
+    def initialize(statsd)
+      @statsd = statsd
+    end
+
+    def batch
+      yield self
+      @statsd.flush(sync: true)
+    end
+  end
+end

lib/cloud_controller/metrics/statsd_updater.rb

@@ -1,4 +1,4 @@
-require 'statsd'
+require 'cloud_controller/metrics/statsd_client_adapter'
 
 module VCAP::CloudController::Metrics
   class StatsdUpdater

spec/unit/controllers/base/base_controller_spec.rb

@@ -9,7 +9,7 @@ module VCAP::CloudController
     let(:config) { double(Config, get: nil) }
     let(:dependencies) do
       {
-        statsd_client: double(Statsd)
+        statsd_client: double(VCAP::CloudController::Metrics::StatsdClientAdapter)
       }
     end
 

spec/unit/controllers/base/model_controller_spec.rb

@@ -8,7 +8,7 @@ module VCAP::CloudController
       {
         object_renderer: nil,
         collection_renderer: nil,
-        statsd_client: double(Statsd)
+        statsd_client: double(VCAP::CloudController::Metrics::StatsdClientAdapter)
       }
     end
     let(:config) { double(Config, get: nil) }

spec/unit/controllers/internal/log_access_controller_spec.rb

@@ -20,7 +20,7 @@ module VCAP::CloudController
         {},
         nil,
         {
-          statsd_client: double(Statsd)
+          statsd_client: double(VCAP::CloudController::Metrics::StatsdClientAdapter)
         }
       )
     end