Class: Datadog::Tracing::Contrib::Sinatra::TracerMiddleware

Inherits:
Object
  • Object
show all
Defined in:
lib/datadog/tracing/contrib/sinatra/tracer_middleware.rb

Overview

Middleware used for automatically tagging configured headers and handle request span

Instance Method Summary collapse

Constructor Details

#initialize(app, opt = {}) ⇒ TracerMiddleware

Returns a new instance of TracerMiddleware.



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# File 'lib/datadog/tracing/contrib/sinatra/tracer_middleware.rb', line 16

def initialize(app, opt = {})
  @app = app
  @app_instance = opt[:app_instance]
end

Instance Method Details

#call(env) ⇒ Object

rubocop:disable Metrics/MethodLength



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# File 'lib/datadog/tracing/contrib/sinatra/tracer_middleware.rb', line 22

def call(env)
  # Find out if this is Sinatra within Sinatra
  return @app.call(env) if Sinatra::Env.datadog_span(env)

  Tracing.trace(
    Ext::SPAN_REQUEST,
    service: configuration[:service_name],
    type: Tracing::Metadata::Ext::HTTP::TYPE_INBOUND
  ) do |span|
    begin
      # this is kept nil until we set a correct one (either in the route or with a fallback in the ensure below)
      # the nil signals that there's no good one yet and is also seen by profiler, when sampling the resource
      span.resource = nil

      Sinatra::Env.set_datadog_span(env, span)

      response = @app.call(env)
    ensure
      Contrib::Rack::HeaderTagging.tag_request_headers(span, env, configuration)

      span.set_tag(Tracing::Metadata::Ext::TAG_COMPONENT, Ext::TAG_COMPONENT)
      span.set_tag(Tracing::Metadata::Ext::TAG_OPERATION, Ext::TAG_OPERATION_REQUEST)

      request = ::Sinatra::Request.new(env)

      span.set_tag(Tracing::Metadata::Ext::HTTP::TAG_URL, request.path)
      span.set_tag(Tracing::Metadata::Ext::HTTP::TAG_METHOD, request.request_method)

      datadog_route = Sinatra::Env.route_path(env)

      span.set_tag(Ext::TAG_ROUTE_PATH, datadog_route) if datadog_route

      if request.script_name && !request.script_name.empty?
        span.set_tag(Ext::TAG_SCRIPT_NAME, request.script_name)
      end

      # If this app handled the request, then Contrib::Sinatra::Tracer OR Contrib::Sinatra::Base set the
      # resource; if no resource was set, let's use a fallback
      span.resource = env['REQUEST_METHOD'] if span.resource.nil?

      rack_request_span = env[Contrib::Rack::Ext::RACK_ENV_REQUEST_SPAN]

      # This propagates the Sinatra resource to the Rack span,
      # since the latter is unaware of what the resource might be
      # and would fallback to a generic resource name when unset
      rack_request_span.resource ||= span.resource if rack_request_span

      if response
        if (status = response[0])
          sinatra_response = ::Sinatra::Response.new([], status) # Build object to use status code helpers

          span.set_tag(Tracing::Metadata::Ext::HTTP::TAG_STATUS_CODE, sinatra_response.status)
          span.set_error(env['sinatra.error']) if sinatra_response.server_error?
        end

        if (headers = response[1])
          Contrib::Rack::HeaderTagging.tag_response_headers(span, headers, configuration)
        end
      end

      # Set analytics sample rate
      Contrib::Analytics.set_sample_rate(span, analytics_sample_rate) if analytics_enabled?

      # Measure service stats
      Contrib::Analytics.set_measured(span)
    end
  end
end