Class: NexusSemanticLogger::DatadogTracer

Inherits:
Object
  • Object
show all
Defined in:
lib/nexus_semantic_logger/datadog_tracer.rb

Instance Method Summary collapse

Constructor Details

#initialize(service) ⇒ DatadogTracer

Returns a new instance of DatadogTracer.



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# File 'lib/nexus_semantic_logger/datadog_tracer.rb', line 7

def initialize(service)
  Datadog.configure do |c|
    # When using a socket, DD_AGENT_HOST will not be set, and DD_TRACE_AGENT_URL will be set instead.
    if ENV['DD_AGENT_HOST'].present? || ENV['DD_TRACE_AGENT_URL'].present?

      # Container and pod names should be set as env vars via the helm chart. Tagging metrics from the app
      # with these values helps correlation with metrics from the kubernetes cluster.
      container_name = ENV.fetch('CONTAINER_NAME') { '' }
      pod_name = ENV.fetch('POD_NAME') { '' }

      # Configure tags to be sent on all metrics.
      # Note that 'env' is NOT sent- that is set as the default on the agent e.g. staging, canary, production.
      # It does not necessarily align with the Rails env, and we do not want to double tag the env.
      global_tags = [
        "railsenv:#{Rails.env}",
        "service:#{service}",
        "container_name:#{container_name}",
        "pod_name:#{pod_name}",
      ]

      # To enable runtime metrics collection, set `true`. Defaults to `false`
      # You can also set DD_RUNTIME_METRICS_ENABLED=true to configure this.
      c.runtime_metrics.enabled = true

      # Configure DogStatsD instance for sending runtime metrics.
      # By default, runtime metrics from the application are sent to the Datadog Agent with DogStatsD on port 8125.
      datadog_singleton = DatadogSingleton.instance
      datadog_statsd_socket_path = ENV.fetch('DD_STATSD_SOCKET_PATH') { '' }
      datadog_singleton.statsd = if datadog_statsd_socket_path.to_s.strip.empty?
        Datadog::Statsd.new(ENV['DD_AGENT_HOST'], 8125, tags: global_tags)
      else
        Datadog::Statsd.new(socket_path: datadog_statsd_socket_path, tags: global_tags)
      end
      c.runtime_metrics.statsd = datadog_singleton.statsd

      # Trace tags API is Hash<String,String>, see https://www.rubydoc.info/gems/ddtrace/Datadog/Tracing
      # Should match the global tags, but as a Hash.
      c.tags = {
        railsenv: Rails.env,
        service: service,
        container_name: container_name,
        pod_name: pod_name,
      }

      # Tracer requires configuration to a datadog agent via DD_AGENT_HOST.
      dd_force_tracer_val = ENV.fetch('DD_FORCE_TRACER', false)
      dd_force_tracer = dd_force_tracer_val.present? && dd_force_tracer_val.to_s == 'true'
      dd_tracer_enabled = Rails.env.production? || dd_force_tracer
      c.tracing.enabled = dd_tracer_enabled

      # Profiling is also provided by datadog, we synchronise their feature toggles.
      c.profiling.enabled = dd_tracer_enabled
    end

    c.tracing.instrument(:rails, service_name: service)

    c.logger.level = Logger::WARN # datadog info logging is too verbose.
  end
end