Trace payload chunking

lib/ddtrace/chunker.rb

@@ -0,0 +1,34 @@
+require 'json'
+require 'msgpack'
+
+module Datadog
+  # Chunks list of elements into batches
+  module Chunker
+    module_function
+
+    # Chunks a list into batches of at most +max_chunk_size+ elements each.
+    #
+    # An exception can occur if a single element is too large. That single
+    # element will be returned in its own chunk. You have to verify by yourself
+    # when such elements are returned.
+    #
+    # @param list [Enumerable] list of elements
+    # @param max_chunk_size [Numeric] maximum acceptable chunk size
+    # @return [Enumerable] lazy list of chunks
+    def chunk_by_size(list, max_chunk_size)
+      chunk_agg = 0
+      list.slice_before do |elem|
+        size = elem.size
+        chunk_agg += size
+        if chunk_agg > max_chunk_size
+          # Can't fit element in current chunk, start a new one.
+          chunk_agg = size
+          true
+        else
+          # Add to current chunk
+          false
+        end
+      end
+    end
+  end
+end

lib/ddtrace/diagnostics/health.rb

@@ -19,6 +19,8 @@ class Metrics < ::Datadog::Metrics
         count :queue_accepted_lengths, Ext::Diagnostics::Health::Metrics::METRIC_QUEUE_ACCEPTED_LENGTHS
         count :queue_dropped, Ext::Diagnostics::Health::Metrics::METRIC_QUEUE_DROPPED
         count :traces_filtered, Ext::Diagnostics::Health::Metrics::METRIC_TRACES_FILTERED
+        count :transport_trace_too_large, Ext::Diagnostics::Health::Metrics::METRIC_TRANSPORT_TRACE_TOO_LARGE
+        count :transport_chunked, Ext::Diagnostics::Health::Metrics::METRIC_TRANSPORT_CHUNKED
         count :writer_cpu_time, Ext::Diagnostics::Health::Metrics::METRIC_WRITER_CPU_TIME
 
         gauge :queue_length, Ext::Diagnostics::Health::Metrics::METRIC_QUEUE_LENGTH

lib/ddtrace/encoding.rb

@@ -10,19 +10,12 @@ def content_type
         raise NotImplementedError
       end
 
-      # Encodes a list of traces, expecting a list of items where each items
-      # is a list of spans. Before dump the string in a serialized format all
-      # traces are normalized. The traces nesting is not changed.
-      def encode_traces(traces)
-        to_send = []
-        traces.each do |trace|
-          to_send << trace.map(&:to_hash)
-        end
-        encode(to_send)
+      # Concatenates a list of elements previously encoded by +#encode+.
+      def join(encoded_elements)
+        raise NotImplementedError
       end
 
-      # Defines the underlying format used during traces or services encoding.
-      # This method must be implemented and should only be used by the internal functions.
+      # Serializes a single trace into a String suitable for network transmission.
       def encode(_)
         raise NotImplementedError
       end
@@ -44,34 +37,8 @@ def encode(obj)
         JSON.dump(obj)
       end
 
-      # New version of JSON Encoder that is API compliant.
-      module V2
-        extend JSONEncoder
-
-        ENCODED_IDS = [
-          :trace_id,
-          :span_id,
-          :parent_id
-        ].freeze
-
-        module_function
-
-        def encode_traces(traces)
-          trace_hashes = traces.collect do |trace|
-            # Convert each trace to hash
-            trace.map(&:to_hash).tap do |spans|
-              # Convert IDs to hexadecimal
-              spans.each do |span|
-                ENCODED_IDS.each do |id|
-                  span[id] = span[id].to_s(16) if span.key?(id)
-                end
-              end
-            end
-          end
-
-          # Wrap traces & encode them
-          encode(traces: trace_hashes)
-        end
+      def join(encoded_data)
+        "[#{encoded_data.join(',')}]"
       end
     end
 
@@ -90,6 +57,13 @@ def content_type
       def encode(obj)
         MessagePack.pack(obj)
       end
+
+      def join(encoded_data)
+        packer = MessagePack::Packer.new
+        packer.write_array_header(encoded_data.size)
+
+        (packer.buffer.to_a + encoded_data).join
+      end
     end
   end
 end

lib/ddtrace/ext/diagnostics.rb

@@ -23,6 +23,8 @@ module Metrics
           METRIC_QUEUE_SPANS = 'datadog.tracer.queue.spans'.freeze
           METRIC_SAMPLING_SERVICE_CACHE_LENGTH = 'datadog.tracer.sampling.service_cache_length'.freeze
           METRIC_TRACES_FILTERED = 'datadog.tracer.traces.filtered'.freeze
+          METRIC_TRANSPORT_CHUNKED = 'datadog.tracer.transport.chunked'.freeze
+          METRIC_TRANSPORT_TRACE_TOO_LARGE = 'datadog.tracer.transport.trace_too_large'.freeze
           METRIC_WRITER_CPU_TIME = 'datadog.tracer.writer.cpu_time'.freeze
         end
       end

lib/ddtrace/transport/http.rb

@@ -19,7 +19,7 @@ module HTTP
 
       # Builds a new Transport::HTTP::Client
       def new(&block)
-        Builder.new(&block).to_client
+        Builder.new(&block).to_transport
       end
 
       # Builds a new Transport::HTTP::Client with default settings

lib/ddtrace/transport/http/api/instance.rb

@@ -15,6 +15,10 @@ def initialize(spec, adapter, options = {})
             @headers = options.fetch(:headers, {})
           end
 
+          def encoder
+            spec.encoder
+          end
+
           def call(env)
             # Add headers to request env, unless empty.
             env.headers.merge!(headers) unless headers.empty?

lib/ddtrace/transport/http/builder.rb

@@ -70,13 +70,11 @@ def default_api=(key)
           @default_api = key
         end
 
-        def to_client
+        def to_transport
           raise NoDefaultApiError if @default_api.nil?
 
-          @client ||= Client.new(
-            to_api_instances,
-            @default_api
-          )
+          # DEV: Should not be specific to traces
+          Transport::Traces::Transport.new(to_api_instances, @default_api)
         end
 
         def to_api_instances

lib/ddtrace/transport/http/client.rb

@@ -8,33 +8,22 @@ module HTTP
       class Client
         include Transport::HTTP::Statistics
 
-        attr_reader \
-          :apis,
-          :current_api_id
+        attr_reader :api
 
-        def initialize(apis, current_api_id)
-          @apis = apis
-
-          # Activate initial API
-          change_api!(current_api_id)
+        def initialize(api)
+          @api = api
         end
 
         def send_request(request, &block)
           # Build request into env
           env = build_env(request)
 
-          # Get response from API
-          response = yield(current_api, env)
+          # Get responses from API
+          response = yield(api, env)
 
           # Update statistics
           update_stats_from_response!(response)
 
-          # If API should be downgraded, downgrade and try again.
-          if downgrade?(response)
-            downgrade!
-            response = send_request(request, &block)
-          end
-
           response
         rescue StandardError => e
           message = "Internal error during HTTP transport request. Cause: #{e.message} Location: #{e.backtrace.first}"
@@ -55,52 +44,6 @@ def send_request(request, &block)
         def build_env(request)
           Env.new(request)
         end
-
-        def downgrade?(response)
-          return false unless apis.fallbacks.key?(current_api_id)
-          response.not_found? || response.unsupported?
-        end
-
-        def current_api
-          apis[current_api_id]
-        end
-
-        def change_api!(api_id)
-          raise UnknownApiVersionError, api_id unless apis.key?(api_id)
-          @current_api_id = api_id
-        end
-
-        def downgrade!
-          downgrade_api_id = apis.fallbacks[current_api_id]
-          raise NoDowngradeAvailableError, current_api_id if downgrade_api_id.nil?
-          change_api!(downgrade_api_id)
-        end
-
-        # Raised when configured with an unknown API version
-        class UnknownApiVersionError < StandardError
-          attr_reader :version
-
-          def initialize(version)
-            @version = version
-          end
-
-          def message
-            "No matching transport API for version #{version}!"
-          end
-        end
-
-        # Raised when configured with an unknown API version
-        class NoDowngradeAvailableError < StandardError
-          attr_reader :version
-
-          def initialize(version)
-            @version = version
-          end
-
-          def message
-            "No downgrade from transport API version #{version} is available!"
-          end
-        end
       end
     end
   end

lib/ddtrace/transport/http/response.rb

@@ -15,7 +15,7 @@ def initialize(http_response)
           @http_response = http_response
         end
 
-        def_delegators :@http_response, *Transport::Response.instance_methods
+        def_delegators :@http_response, *Datadog::Transport::Response.instance_methods
 
         def code
           @http_response.respond_to?(:code) ? @http_response.code : nil

lib/ddtrace/transport/http/statistics.rb

@@ -6,7 +6,7 @@ module HTTP
       # Tracks statistics for HTTP transports
       module Statistics
         def self.included(base)
-          base.send(:include, Transport::Statistics)
+          base.send(:include, Datadog::Transport::Statistics)
           base.send(:include, InstanceMethods)
         end
 

lib/ddtrace/transport/http/traces.rb

@@ -12,19 +12,18 @@ module Traces
         # Response from HTTP transport for traces
         class Response
           include HTTP::Response
-          include Transport::Traces::Response
+          include Datadog::Transport::Traces::Response
 
           def initialize(http_response, options = {})
             super(http_response)
             @service_rates = options.fetch(:service_rates, nil)
+            @trace_count = options.fetch(:trace_count, 0)
           end
         end
 
         # Extensions for HTTP client
         module Client
-          def send_traces(traces)
-            request = Transport::Traces::Request.new(traces)
-
+          def send_payload(request)
             send_request(request) do |api, env|
               api.send_traces(env)
             end
@@ -45,6 +44,10 @@ def send_traces(env, &block)
               traces.call(env, &block)
             end
 
+            def encoder
+              traces.encoder
+            end
+
             # Raised when traces sent but no traces endpoint is defined
             class NoTraceEndpointDefinedError < StandardError
               attr_reader :spec
@@ -104,17 +107,17 @@ def service_rates?
 
             def call(env, &block)
               # Add trace count header
-              env.headers[HEADER_TRACE_COUNT] = env.request.parcel.count.to_s
+              env.headers[HEADER_TRACE_COUNT] = env.request.parcel.trace_count.to_s
 
               # Encode body & type
               env.headers[HEADER_CONTENT_TYPE] = encoder.content_type
-              env.body = env.request.parcel.encode_with(encoder)
+              env.body = env.request.parcel.data
 
               # Query for response
               http_response = super(env, &block)
 
               # Process the response
-              response_options = {}.tap do |options|
+              response_options = { trace_count: env.request.parcel.trace_count }.tap do |options|
                 # Parse service rates, if configured to do so.
                 if service_rates? && !http_response.payload.to_s.empty?
                   body = JSON.parse(http_response.payload)

lib/ddtrace/transport/io.rb

@@ -18,7 +18,7 @@ def new(out, encoder)
       def default(options = {})
         new(
           options.fetch(:out, STDOUT),
-          options.fetch(:encoder, Encoding::JSONEncoder::V2)
+          options.fetch(:encoder, Encoding::JSONEncoder)
         )
       end
     end

lib/ddtrace/transport/io/response.rb

@@ -6,12 +6,14 @@ module IO
       # Response from HTTP transport for traces
       class Response
         include Transport::Response
+        include Transport::Traces::Response
 
         attr_reader \
           :result
 
-        def initialize(result)
+        def initialize(result, trace_count = 1)
           @result = result
+          @trace_count = trace_count
         end
 
         def ok?