feat: setup datadog instrumentation

Gemfile3

@@ -70,3 +70,4 @@ gem "rack-contrib", :git => 'https://github.com/rack/rack-contrib.git', :ref =>
 
 
 gem "timecop", "~> 0.9.5"
+gem 'ddtrace', require: 'ddtrace/auto_instrument'

Gemfile3.lock

@@ -37,6 +37,15 @@ GEM
       bigdecimal
       rexml
     dalli (3.2.8)
+    datadog-ci (0.8.3)
+      msgpack
+    ddtrace (1.21.1)
+      datadog-ci (~> 0.8.1)
+      debase-ruby_core_source (= 3.3.1)
+      libdatadog (~> 6.0.0.2.0)
+      libddwaf (~> 1.14.0.0.0)
+      msgpack
+    debase-ruby_core_source (3.3.1)
     delayed_job (4.1.11)
       activesupport (>= 3.0, < 8.0)
     delayed_job_mongoid (3.0.0)
@@ -107,6 +116,15 @@ GEM
     i18n (1.14.1)
       concurrent-ruby (~> 1.0)
     kgio (2.11.4)
+    libdatadog (6.0.0.2.0)
+    libdatadog (6.0.0.2.0-aarch64-linux)
+    libdatadog (6.0.0.2.0-x86_64-linux)
+    libddwaf (1.14.0.0.0-aarch64-linux)
+      ffi (~> 1.0)
+    libddwaf (1.14.0.0.0-arm64-darwin)
+      ffi (~> 1.0)
+    libddwaf (1.14.0.0.0-x86_64-linux)
+      ffi (~> 1.0)
     listen (3.8.0)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
@@ -128,6 +146,7 @@ GEM
     mongoid_magic_counter_cache (1.1.1)
       mongoid
       rake
+    msgpack (1.7.2)
     multi_json (1.15.0)
     multipart-post (2.4.0)
     mustermann (3.0.0)
@@ -235,6 +254,7 @@ DEPENDENCIES
   bundler
   codecov
   dalli
+  ddtrace
   delayed_job
   delayed_job_mongoid
   elasticsearch (~> 7.8.0)

config.ru

@@ -20,3 +20,4 @@ use Mongoid::QueryCache::Middleware
 
 require './app'
 run Sinatra::Application
+

config/unicorn_tcp.rb

@@ -10,6 +10,14 @@
 timeout 25
 preload_app true
 
+service_name = 'forum'
+
+# Add Datadog APM configuration
+Datadog.configure do |c|
+  c.use :rails, service_name: service_name
+  c.use :sinatra, service_name: service_name
+end
+
 listen_host = ENV['LISTEN_HOST'] || '0.0.0.0'
 listen_port = ENV['LISTEN_PORT'] || '4567'
 listen "#{listen_host}:#{listen_port}", :tcp_nopush => true, :backlog => 512
@@ -20,8 +28,11 @@
 after_fork do |server, worker|
   ::Mongoid.default_client.close
   ::Mongoid.default_client.reconnect
+  Datadog.tracer.provider.context_flush
+  Datadog.tracer.provider.context_flush
 end
 
 before_fork do |server, worker|
   ::Mongoid.disconnect_clients
+  Datadog.tracer.shutdown! if defined?(Datadog) && Datadog.tracer
 end