Add support for automated resource detection

This adds support for populating a resource with with Telemetry data
as well as Google Cloud Platform environment metata data.

For #230

sdk/lib/opentelemetry/sdk/configurator.rb

@@ -16,7 +16,7 @@ class Configurator
       private_constant :USE_MODE_UNSPECIFIED, :USE_MODE_ONE, :USE_MODE_ALL
 
       attr_writer :logger, :http_extractors, :http_injectors, :text_extractors,
-                  :text_injectors
+                  :text_injectors, :resource
 
       def initialize
         @adapter_names = []
@@ -27,7 +27,7 @@ def initialize
         @text_injectors = nil
         @span_processors = []
         @use_mode = USE_MODE_UNSPECIFIED
-        @tracer_provider = Trace::TracerProvider.new
+        @resource = OpenTelemetry::SDK::Resources::Resource.create
       end
 
       def logger
@@ -83,12 +83,16 @@ def configure
         OpenTelemetry.correlations = CorrelationContext::Manager.new
         configure_propagation
         configure_span_processors
-        OpenTelemetry.tracer_provider = @tracer_provider
+        OpenTelemetry.tracer_provider = tracer_provider
         install_instrumentation
       end
 
       private
 
+      def tracer_provider
+        @tracer_provider ||= Trace::TracerProvider.new(@resource)
+      end
+
       def check_use_mode!(mode)
         @use_mode = mode if @use_mode == USE_MODE_UNSPECIFIED
         raise 'Use either `use_all` or `use`, but not both' unless @use_mode == mode
@@ -105,7 +109,7 @@ def install_instrumentation
 
       def configure_span_processors
         processors = @span_processors.empty? ? [default_span_processor] : @span_processors
-        processors.each { |p| @tracer_provider.add_span_processor(p) }
+        processors.each { |p| tracer_provider.add_span_processor(p) }
       end
 
       def default_span_processor

sdk/lib/opentelemetry/sdk/resources.rb

@@ -13,3 +13,5 @@ module Resources
 end
 
 require 'opentelemetry/sdk/resources/resource'
+require 'opentelemetry/sdk/resources/constants'
+require 'opentelemetry/sdk/resources/auto_detector'

sdk/lib/opentelemetry/sdk/resources/auto_detector.rb

@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require 'opentelemetry/sdk/resources/detectors/google_cloud_platform'
+require 'opentelemetry/sdk/resources/detectors/telemetry'
+
+module OpenTelemetry
+  module SDK
+    module Resources
+      module AutoDetector
+        extend self
+
+        DETECTORS = [
+          OpenTelemetry::SDK::Resources::Detectors::GoogleCloudPlatform,
+          OpenTelemetry::SDK::Resources::Detectors::Telemetry
+        ]
+
+        def detect
+          resources = DETECTORS.map do |detector|
+            detector.detect
+          end
+
+          resources.reduce(OpenTelemetry::SDK::Resources::Resource.create) do |empty_resource, detected_resource|
+            empty_resource.merge(detected_resource)
+          end
+        end
+      end
+    end
+  end
+end

sdk/lib/opentelemetry/sdk/resources/constants.rb

@@ -0,0 +1,122 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+module OpenTelemetry
+  module SDK
+    module Resources
+      # Attributes describing a service instance.
+      SERVICE_RESOURCE = {
+        # Logical name of the service.
+        name: 'service.name',
+
+        # A namespace for `service.name`.
+        namespace: 'service.namespace',
+
+        # The string ID of the service instance.
+        instance_id: 'service.instance.id',
+
+        # The version string of the service API or implementation.
+        version: 'service.version'
+      }.freeze
+
+      # Attributes describing the telemetry library.
+      TELEMETRY_SDK_RESOURCE = {
+        # The name of the telemetry library.
+        name: 'telemetry.sdk.name',
+
+        # The language of telemetry library and of the code instrumented with it.
+        language: 'telemetry.sdk.language',
+
+        # The version string of the telemetry library
+        version: 'telemetry.sdk.version'
+      }.freeze
+
+      # Attributes defining a compute unit (e.g. Container, Process, Lambda
+      # Function).
+      CONTAINER_RESOURCE = {
+        # The container name.
+        name: 'container.name',
+
+        # The name of the image the container was built on.
+        image_name: 'container.image.name',
+
+        # The container image tag.
+        image_tag: 'container.image.tag'
+      }.freeze
+
+      FAAS_RESOURCE = {
+        # The name of the function being executed.
+        name: 'faas.name',
+
+        # The unique name of the function being executed.
+        id: 'faas.id',
+
+        # The version string of the function being executed.
+        version: 'faas.version',
+
+        # The execution environment ID as a string.
+        instance: 'faas.instance'
+      }.freeze
+
+      # Attributes defining a deployment service (e.g. Kubernetes).
+      K8S_RESOURCE = {
+        # The name of the cluster that the pod is running in.
+        cluster_name: 'k8s.cluster.name',
+
+        # The name of the namespace that the pod is running in.
+        namespace_name: 'k8s.namespace.name',
+
+        # The name of the pod.
+        pod_name: 'k8s.pod.name',
+
+        # The name of the deployment.
+        deployment_name: 'k8s.deployment.name'
+      }.freeze
+
+      # Attributes defining a computing instance (e.g. host).
+      HOST_RESOURCE = {
+        # Hostname of the host. It contains what the hostname command returns on the
+        # host machine.
+        hostname: 'host.hostname',
+
+        # Unique host id. For Cloud this must be the instance_id assigned by the
+        # cloud provider
+        id: 'host.id',
+
+        # Name of the host. It may contain what hostname returns on Unix systems,
+        # the fully qualified, or a name specified by the user.
+        name: 'host.name',
+
+        # Type of host. For Cloud this must be the machine type.
+        type: 'host.type',
+
+        # Name of the VM image or OS install the host was instantiated from.
+        image_name: 'host.image.name',
+
+        # VM image id. For Cloud, this value is from the provider.
+        image_id: 'host.image.id',
+
+        # The version string of the VM image.
+        image_version: 'host.image.version'
+      }.freeze
+
+      # Attributes defining a running environment (e.g. Cloud, Data Center).
+      CLOUD_RESOURCE = {
+        # Name of the cloud provider. Example values are aws, azure, gcp.
+        provider: 'cloud.provider',
+
+        # The cloud account id used to identify different entities.
+        account_id: 'cloud.account.id',
+
+        # A specific geographical location where different entities can run.
+        region: 'cloud.region',
+
+        # Zones are a sub set of the region connected through low-latency links.
+        zone: 'cloud.zone'
+      }.freeze
+    end
+  end
+end

sdk/lib/opentelemetry/sdk/resources/detectors/google_cloud_platform.rb

@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require 'google-cloud-env'
+
+module OpenTelemetry
+  module SDK
+    module Resources
+      module Detectors
+        module GoogleCloudPlatform
+          extend self
+
+          def detect
+            gcp_env = Google::Cloud::Env.new
+            return Resource.create unless gcp_env.compute_engine?
+
+            resource_labels = {}
+            resource_labels[CLOUD_RESOURCE[:provider]] = 'gcp'
+            resource_labels[CLOUD_RESOURCE[:account_id]] = gcp_env.project_id || ''
+            resource_labels[CLOUD_RESOURCE[:region]] = gcp_env.instance_attribute('cluster-location') || ''
+            resource_labels[CLOUD_RESOURCE[:zone]] = gcp_env.instance_zone || ''
+
+            resource_labels[HOST_RESOURCE[:hostname]] = hostname
+            resource_labels[HOST_RESOURCE[:id]] = gcp_env.lookup_metadata('instance', 'id') || ''
+            resource_labels[HOST_RESOURCE[:name]] = gcp_env.lookup_metadata('instance', 'hostname') || ''
+
+            if gcp_env.kubernetes_engine?
+              resource_labels[K8S_RESOURCE[:cluster_name]] = gcp_env.instance_attribute('cluster-name') || ''
+              resource_labels[K8S_RESOURCE[:namespace_name]] = gcp_env.kubernetes_engine_namespace_id || ''
+              resource_labels[K8S_RESOURCE[:pod_name]] = hostname
+
+              resource_labels[CONTAINER_RESOURCE[:name]] = ENV['CONTAINER_NAME'] || ''
+            end
+
+            Resource.create(resource_labels)
+          end
+
+          private
+
+          def hostname
+            ENV['HOSTNAME'] || `hostname`&.strip
+          rescue
+            ''
+          end
+        end
+      end
+    end
+  end
+end

sdk/lib/opentelemetry/sdk/resources/detectors/telemetry.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+module OpenTelemetry
+  module SDK
+    module Resources
+      module Detectors
+        module Telemetry
+          extend self
+
+          def detect
+            resource_labels = {}
+            resource_labels[TELEMETRY_SDK_RESOURCE[:name]] = 'OpenTelemetry'
+            resource_labels[TELEMETRY_SDK_RESOURCE[:language]] = 'ruby'
+            resource_labels[TELEMETRY_SDK_RESOURCE[:version]] = "semver:#{OpenTelemetry::SDK::VERSION}"
+            Resource.create(resource_labels)
+          end
+        end
+      end
+    end
+  end
+end

sdk/lib/opentelemetry/sdk/resources/resource.rb

@@ -74,3 +74,4 @@ def merge(other)
     end
   end
 end
+

sdk/lib/opentelemetry/sdk/trace/tracer.rb

@@ -9,21 +9,17 @@ module SDK
     module Trace
       # {Tracer} is the SDK implementation of {OpenTelemetry::Trace::Tracer}.
       class Tracer < OpenTelemetry::Trace::Tracer
-        attr_reader :name
-        attr_reader :version
+        attr_reader :resource
 
         # @api private
         #
         # Returns a new {Tracer} instance.
         #
-        # @param [String] name Instrumentation package name
-        # @param [String] version Instrumentation package version
+        # @param [Resource] resource Containing name and version arguments supplied to the TracerProvider
         #
         # @return [Tracer]
-        def initialize(name, version)
-          @name = name
-          @version = version
-          @resource = Resources::Resource.create('name' => name, 'version' => version)
+        def initialize(resource)
+          @resource = resource
         end
 
         def start_root_span(name, attributes: nil, links: nil, start_timestamp: nil, kind: nil)

sdk/lib/opentelemetry/sdk/trace/tracer_provider.rb

@@ -20,13 +20,14 @@ class TracerProvider < OpenTelemetry::Trace::TracerProvider
         # Returns a new {TracerProvider} instance.
         #
         # @return [TracerProvider]
-        def initialize
+        def initialize(resource = OpenTelemetry::SDK::Resources::Resource.create)
           @mutex = Mutex.new
           @registry = {}
           @active_span_processor = NoopSpanProcessor.instance
           @active_trace_config = Config::TraceConfig::DEFAULT
           @registered_span_processors = []
           @stopped = false
+          @resource = resource
         end
 
         # Returns a {Tracer} instance.
@@ -38,7 +39,8 @@ def initialize
         def tracer(name = nil, version = nil)
           name ||= ''
           version ||= ''
-          @mutex.synchronize { @registry[Key.new(name, version)] ||= Tracer.new(name, version) }
+          resource = @resource.merge(OpenTelemetry::SDK::Resources::Resource.create({ 'name' => name, 'version' => version }))
+          @mutex.synchronize { @registry[Key.new(name, version)] ||= Tracer.new(resource) }
         end
 
         # Attempts to stop all the activity for this {Tracer}. Calls

sdk/opentelemetry-sdk.gemspec

@@ -26,6 +26,7 @@ Gem::Specification.new do |spec|
   spec.required_ruby_version = '>= 2.5.0'
 
   spec.add_dependency 'opentelemetry-api', '~> 0.4.0'
+  spec.add_dependency 'google-cloud-env'
 
   spec.add_development_dependency 'bundler', '>= 1.17'
   spec.add_development_dependency 'faraday', '~> 0.13'

sdk/test/opentelemetry/sdk/resources/auto_detector_test.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+# Copyright 2019 OpenTelemetry Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+require 'test_helper'
+
+describe OpenTelemetry::SDK::Resources::AutoDetector do
+  let(:auto_detector) { OpenTelemetry::SDK::Resources::AutoDetector }
+  let(:detected_resource) { auto_detector.detect }
+  let(:detected_resource_labels) { detected_resource.label_enumerator.to_h }
+  let(:expected_resource_labels) do
+    {
+      'telemetry.sdk.name' => 'OpenTelemetry',
+      'telemetry.sdk.language' => 'ruby',
+      'telemetry.sdk.version' => 'semver:0.4.0'
+    }
+  end
+
+  describe '.detect' do
+    it 'returns detected resources' do
+      _(detected_resource).must_be_instance_of(OpenTelemetry::SDK::Resources::Resource)
+      _(detected_resource_labels).must_equal(expected_resource_labels)
+    end
+  end
+end