Attempt to instrument mongodb queries

Gemfile

@@ -95,3 +95,5 @@ gem "faraday-follow_redirects", "~> 0.3.0"
 gem "opentelemetry-sdk", "~> 1.7"
 gem "opentelemetry-exporter-otlp", "~> 0.29.1"
 gem "opentelemetry-instrumentation-all", "~> 0.74.0"
+
+gem "mongoid", "~> 9.0"

Gemfile.lock

@@ -84,6 +84,7 @@ GEM
     bindex (0.8.1)
     bootsnap (1.18.4)
       msgpack (~> 1.2)
+    bson (5.0.2)
     builder (3.3.0)
     bump (0.10.0)
     capybara (3.40.0)
@@ -243,6 +244,12 @@ GEM
       railties (>= 7.1)
       stimulus-rails
       turbo-rails
+    mongo (2.21.0)
+      bson (>= 4.14.1, < 6.0.0)
+    mongoid (9.0.6)
+      activemodel (>= 5.1, < 8.1, != 7.0.0)
+      concurrent-ruby (>= 1.0.5, < 2.0)
+      mongo (>= 2.18.0, < 3.0.0)
     msgpack (1.7.3)
     multi_json (1.15.0)
     multi_xml (0.7.1)
@@ -743,6 +750,7 @@ DEPENDENCIES
   memory_profiler (~> 1.1)
   mini_magick (~> 5.0)
   mission_control-jobs (~> 0.6.0)
+  mongoid (~> 9.0)
   opentelemetry-exporter-otlp (~> 0.29.1)
   opentelemetry-instrumentation-all (~> 0.74.0)
   opentelemetry-sdk (~> 1.7)

app/controllers/patterns_controller.rb

@@ -4,6 +4,7 @@ class PatternsController < ApplicationController
   skip_before_action :verify_authenticity_token
 
   def new
+    LogEntry.where(message: "Pattern created").first
     render :new
   end
 

config/initializers/mongoid.rb

@@ -0,0 +1,25 @@
+# rubocop:todo all
+Mongoid.configure do
+  target_version = "9.0"
+
+  # Load Mongoid behavior defaults. This automatically sets
+  # features flags (refer to documentation)
+  config.load_defaults target_version
+
+  # It is recommended to use config/mongoid.yml for most Mongoid-related
+  # configuration, whenever possible, but if you prefer, you can set
+  # configuration values here, instead:
+  # 
+  #   config.log_level = :debug
+  #
+  # Note that the settings in config/mongoid.yml always take precedence,
+  # whatever else is set here.
+end
+
+# Enable Mongo driver query cache for Rack
+# Rails.application.config.middleware.use(Mongo::QueryCache::Middleware)
+
+# Enable Mongo driver query cache for ActiveJob
+# ActiveSupport.on_load(:active_job) do
+#   include Mongo::QueryCache::Middleware::ActiveJob
+# end

config/initializers/opentelemetry.rb

@@ -0,0 +1,56 @@
+# config/initializer/opentelemetry.rb
+
+require "opentelemetry/sdk"
+require "opentelemetry/exporter/otlp"
+require "opentelemetry/instrumentation/all"
+
+class BatchSpanProcessorWithDbStatementFlattening < OpenTelemetry::SDK::Trace::Export::BatchSpanProcessor
+  def on_start(span, context)
+    # This is where we modify spans before they start.
+    statement = span.attributes["db.statement"]
+    if statement
+      begin
+        # Recursively convert nested JSON attributes to dotted format
+        def flatten_json(obj, prefix = "")
+          attributes = {}
+          obj.each do |key, value|
+            if value.is_a?(Hash)
+              attributes.merge!(flatten_json(value, "#{prefix}#{key}."))
+            else
+              attributes["#{prefix}#{key}"] = value
+            end
+          end
+          attributes
+        end
+
+        parsed_statement = JSON.parse(statement)
+        flatten_json(parsed_statement).each do |key, value|
+          span.set_attribute("db.statement.#{key}", value)
+        end
+      rescue JSON::ParserError
+      end
+    end
+    super(span, context)
+  end
+end
+
+
+OpenTelemetry::SDK.configure do |c|
+  c.use_all(
+    "OpenTelemetry::Instrumentation::ActiveJob" => {
+      propagation_style: :link,
+      span_naming: :job_class
+    },
+    "OpenTelemetry::Instrumentation::Mongo" => {
+      db_statement: :include
+    }
+  )
+  c.resource = OpenTelemetry::SDK::Resources::Resource.create(
+    "service.commit_sha" => `git rev-parse HEAD`.strip
+  )
+  c.add_span_processor(
+    BatchSpanProcessorWithDbStatementFlattening.new(
+      OpenTelemetry::Exporter::OTLP::Exporter.new
+    )
+  )
+end