Module: Datadog::Contrib::HTTP::Patcher

Defined in:
lib/ddtrace/contrib/http/patcher.rb

Overview

Patcher enables patching of ‘net/http’ module. This is used in monkey.rb to automatically apply patches

Class Method Summary collapse

Class Method Details

.patch ⇒ Object

patch applies our patch if needed



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# File 'lib/ddtrace/contrib/http/patcher.rb', line 59

def patch
  unless @patched
    begin
      require 'uri'
      require 'ddtrace/pin'
      require 'ddtrace/monkey'
      require 'ddtrace/ext/app_types'
      require 'ddtrace/ext/http'
      require 'ddtrace/ext/net'
      require 'ddtrace/ext/distributed'

      patch_http()

      @patched = true
    rescue StandardError => e
      Datadog::Tracer.log.error("Unable to apply net/http integration: #{e}")
    end
  end
  @patched
end

.patch_http ⇒ Object

rubocop:disable Metrics/MethodLength rubocop:disable Metrics/BlockLength rubocop:disable Metrics/AbcSize



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# File 'lib/ddtrace/contrib/http/patcher.rb', line 88

def patch_http
  ::Net::HTTP.class_eval do
    alias_method :initialize_without_datadog, :initialize
    Datadog::Monkey.without_warnings do
      remove_method :initialize
    end

    def initialize(*args)
      pin = Datadog::Pin.new(SERVICE, app: APP, app_type: Datadog::Ext::AppTypes::WEB)
      pin.onto(self)
      initialize_without_datadog(*args)
    end

    alias_method :request_without_datadog, :request
    remove_method :request

    def request(req, body = nil, &block) # :yield: +response+
      pin = Datadog::Pin.get_from(self)
      return request_without_datadog(req, body, &block) unless pin && pin.tracer

      transport = pin.tracer.writer.transport
      return request_without_datadog(req, body, &block) if
        Datadog::Contrib::HTTP.should_skip_tracing?(req, @address, @port, transport, pin)

      pin.tracer.trace(NAME) do |span|
        begin
          span.service = pin.service
          span.span_type = Datadog::Ext::HTTP::TYPE

          span.resource = req.method
          # Using the method as a resource, as URL/path can trigger
          # a possibly infinite number of resources.
          span.set_tag(Datadog::Ext::HTTP::URL, req.path)
          span.set_tag(Datadog::Ext::HTTP::METHOD, req.method)

          unless Datadog::Contrib::HTTP.should_skip_distributed_tracing?(pin)
            req.add_field(Datadog::Ext::DistributedTracing::HTTP_HEADER_TRACE_ID, span.trace_id)
            req.add_field(Datadog::Ext::DistributedTracing::HTTP_HEADER_PARENT_ID, span.span_id)
          end
        rescue StandardError => e
          Datadog::Tracer.log.error("error preparing span for http request: #{e}")
        ensure
          response = request_without_datadog(req, body, &block)
        end
        span.set_tag(Datadog::Ext::HTTP::STATUS_CODE, response.code)
        if req.respond_to?(:uri) && req.uri
          span.set_tag(Datadog::Ext::NET::TARGET_HOST, req.uri.host)
          span.set_tag(Datadog::Ext::NET::TARGET_PORT, req.uri.port.to_s)
        else
          span.set_tag(Datadog::Ext::NET::TARGET_HOST, @address)
          span.set_tag(Datadog::Ext::NET::TARGET_PORT, @port.to_s)
        end

        case response.code.to_i / 100
        when 4
          span.set_error(response)
        when 5
          span.set_error(response)
        end

        response
      end
    end
  end
end

.patched? ⇒ Boolean

patched? tells wether patch has been successfully applied

Returns:

  • (Boolean) 


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# File 'lib/ddtrace/contrib/http/patcher.rb', line 81

def patched?
  @patched
end