Add config transport endpoint

.env

@@ -4,6 +4,7 @@ DD_API_KEY=00000000000000000000000000000000
 DD_METRIC_AGENT_PORT=8125
 DD_TRACE_AGENT_PORT=8126
 DD_INSTRUMENTATION_TELEMETRY_ENABLED=false
+DD_REMOTE_CONFIGURATION_ENABLED=true
 TEST_DDAGENT_VAR_RUN=/var/run/datadog
 TEST_DDAGENT_UNIX_SOCKET=${TEST_DDAGENT_VAR_RUN}/apm.socket
 TEST_DDAGENT_API_KEY=invalid_key_but_this_is_fine

Steepfile

@@ -654,6 +654,8 @@ target :ddtrace do
   library 'json'
   library 'ipaddr'
   library 'net-http'
+  library 'securerandom'
+  library 'base64'
 
   # TODO: gem 'libddwaf'
 

docker-compose.yml

@@ -366,6 +366,7 @@ services:
       - "DD_API_KEY=${DD_API_KEY}"
       - DD_HOSTNAME=dd-trace-rb-ci
       - DD_APM_RECEIVER_SOCKET=/var/run/datadog/apm.socket
+      - DD_REMOTE_CONFIGURATION_ENABLED=true
     expose:
       - "8125/udp"
       - "8126"

lib/datadog/core/transport/config.rb

@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+require_relative '../../../ddtrace/transport/request'
+require_relative '../../../ddtrace/transport/parcel'
+
+module Datadog
+  module Core
+    module Transport
+      module Config
+        # Data transfer object for encoded traces
+        class EncodedParcel
+          include Datadog::Transport::Parcel
+
+          def count
+            data.length
+          end
+        end
+
+        # Config request
+        class Request < Datadog::Transport::Request
+        end
+
+        # Config response
+        module Response
+          attr_reader :roots, :targets, :target_files, :client_configs
+        end
+
+        # Config transport
+        class Transport
+          attr_reader :client, :apis, :default_api, :current_api_id
+
+          def initialize(apis, default_api)
+            @apis = apis
+
+            @client = HTTP::Client.new(current_api)
+          end
+
+          ##### there is only one transport! it's negotiation!
+          def send_config(payload)
+            json = JSON.dump(payload)
+            parcel = EncodedParcel.new(json)
+            request = Request.new(parcel)
+
+            @client.send_config_payload(request)
+          end
+
+          def current_api
+            @apis[HTTP::API::V7]
+          end
+        end
+      end
+    end
+  end
+end

lib/datadog/core/transport/http.rb

@@ -84,6 +84,35 @@ def root(
           end
         end
 
+        # Builds a new Transport::HTTP::Client with default settings
+        # Pass a block to override any settings.
+        def v7(
+          agent_settings: DO_NOT_USE_ENVIRONMENT_AGENT_SETTINGS,
+          **options
+        )
+          new(Transport::Config::Transport) do |transport|
+            transport.adapter(agent_settings)
+            transport.headers default_headers
+
+            apis = API.defaults
+
+            transport.api API::V7, apis[API::V7]
+
+            # Apply any settings given by options
+            unless options.empty?
+              transport.default_api = options[:api_version] if options.key?(:api_version)
+              transport.headers options[:headers] if options.key?(:headers)
+            end
+
+            if agent_settings.deprecated_for_removal_transport_configuration_proc
+              agent_settings.deprecated_for_removal_transport_configuration_proc.call(transport)
+            end
+
+            # Call block to apply any customization, if provided
+            yield(transport) if block_given?
+          end
+        end
+
         def default_headers
           {
             Datadog::Transport::Ext::HTTP::HEADER_CLIENT_COMPUTED_TOP_LEVEL => '1',

lib/datadog/core/transport/http/api.rb

@@ -20,6 +20,9 @@
 # TODO: only needed for Negotiation::API::Endpoint
 require_relative 'negotiation'
 
+# TODO: only needed for Config::API::Endpoint
+require_relative 'config'
+
 module Datadog
   module Core
     module Transport
@@ -28,6 +31,7 @@ module HTTP
         module API
           # Default API versions
           ROOT = 'root'
+          V7 = 'v0.7'
 
           module_function
 
@@ -38,6 +42,12 @@ def defaults
                   '/info',
                 )
               end,
+              V7 => Spec.new do |s|
+                s.config = Config::API::Endpoint.new(
+                  '/v0.7/config',
+                  Core::Encoding::JSONEncoder,
+                )
+              end,
             ]
           end
         end