feat: Add preconfigured support for Smart Agent

README.md

@@ -203,7 +203,7 @@ end
 ```
 
 And add the middleware in `Rack::Builder`:
- 
+
 ``` ruby
 Rack::Builder.app do
     use OpenTelemetry::Instrumentation::Rack::Middlewares::TracerMiddleware
@@ -227,6 +227,14 @@ To disable the response headers being added the environment variable
 `SPLUNK_TRACE_RESPONSE_HEADER_ENABLED` can be set to `false`, or pass
 `trace_response_header_enabled: false` to `Splunk::Otel.configure`.
 
+## Configure for use with Smart Agent
+
+This distribution includes the `jaeger-thrift-splunk` exporter, which is preconfigured to send data to local instance of the [SignalFx Smart Agent](https://github.com/signalfx/signalfx-agent).
+
+To use the `jaeger-thrift-splunk` exporter, set the`OTEL_TRACES_EXPORTER` environment variable to `jaeger-thrift-splunk`, or append the exporter to the existing values. For example,  `OTEL_TRACES_EXPORTER=otlp,jaeger-thrift-splunk`.
+
+If the `SPLUNK_REALM` or the `OTEL_EXPORTER_JAEGER_ENDPOINT` environmental variables are set, the default endpoint is overwritten.
+
 ## Troubleshooting
 
 For troubleshooting information, see the [Troubleshooting](docs/troubleshooting.md) documentation.

examples/smart-agent/.gitignore

@@ -0,0 +1 @@
+Gemfile.lock

examples/smart-agent/Gemfile

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+source "https://rubygems.org"
+
+gem "opentelemetry-exporter-jaeger"
+gem "splunk-otel", path: "../../"

examples/smart-agent/docker-compose.yml

@@ -0,0 +1,8 @@
+version: "3"
+services:
+  otel:
+    image: quay.io/signalfx/signalfx-agent:5
+    ports:
+      - 9080:9080
+    volumes:
+      - ./smart-agent-config.yaml:/etc/signalfx/agent.yaml

examples/smart-agent/runner.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require "rubygems"
+require "bundler/setup"
+Bundler.require(:default)
+
+Splunk::Otel.configure do |configurator|
+  $configurator = configurator # rubocop:disable Style/GlobalVars
+
+  class << configurator
+    def test_shutdown
+      @span_processors.each(&:shutdown)
+    end
+  end
+end
+
+tracer = OpenTelemetry.tracer_provider.tracer("test", "1.0")
+tracer.in_span("test-span") do
+  puts "test-span execution"
+end
+
+$configurator.test_shutdown # rubocop:disable Style/GlobalVars

examples/smart-agent/smart-agent-config.yaml

@@ -0,0 +1,5 @@
+signalFxAccessToken: ""
+ingestUrl: "https://ingest.lab0.signalfx.com"
+signalFxRealm: "lab0"
+monitors:
+  - type: trace-forwarder

lib/splunk/otel.rb

@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require_relative "otel/version"
 require "opentelemetry/sdk"
-
-# FIXME: without this, otlp doesn't work out-of-the-box
 require "opentelemetry-exporter-otlp"
 
+require_relative "otel/version"
+require_relative "otel/proprietary_exporters"
+
 module Splunk
   # main module for application startup configuration
-  module Otel
+  module Otel # rubocop:disable Metrics/ModuleLength
     # custom exception types in this gem must inherit from Splunk::Otel::Error
     # this allows the user to rescue a generic exception type to catch all exceptions
     class Error < StandardError; end
@@ -57,20 +57,21 @@ def configure(service_name: ENV.fetch("OTEL_SERVICE_NAME", "unnamed-ruby-service
                   trace_response_header_enabled: ENV.fetch("SPLUNK_TRACE_RESPONSE_HEADER_ENABLED", "true"))
       @trace_response_header_enabled = to_boolean(trace_response_header_enabled)
 
-      set_default_propagators
-      set_access_token_header
-      set_default_exporter
-      set_default_span_limits
+      set_defaults
 
       # run SDK's setup function
-      OpenTelemetry::SDK.configure do |c|
-        c.service_name = service_name
-        c.resource = OpenTelemetry::SDK::Resources::Resource.create(
+      OpenTelemetry::SDK.configure do |configurator|
+        class << configurator
+          include Splunk::Otel::ExporterExtensions
+        end
+
+        configurator.service_name = service_name
+        configurator.resource = OpenTelemetry::SDK::Resources::Resource.create(
           "splunk.distro.version" => Splunk::Otel::VERSION
         )
 
-        c.use_all if auto_instrument
-        yield c if block_given?
+        configurator.use_all if auto_instrument
+        yield configurator if block_given?
       end
 
       # set span limits to GDI defaults if not set by the user
@@ -79,6 +80,13 @@ def configure(service_name: ENV.fetch("OTEL_SERVICE_NAME", "unnamed-ruby-service
       verify_service_name
     end
 
+    def set_defaults
+      set_default_propagators
+      set_access_token_header
+      set_default_exporter
+      set_default_span_limits
+    end
+
     # verify `service.name` is set and print a warning if it is still the default
     def verify_service_name
       provider_resource = OpenTelemetry.tracer_provider.instance_variable_get(:@resource)
@@ -183,7 +191,7 @@ def service_name_warning
     module_function :configure, :gdi_span_limits, :set_default_propagators, :set_default_exporter,
                     :verify_service_name, :service_name_warning, :default_env_vars,
                     :set_default_span_limits, :set_access_token_header, :set_endpoint,
-                    :to_boolean, :trace_response_header_enabled
+                    :to_boolean, :trace_response_header_enabled, :set_defaults
   end
 end
 

lib/splunk/otel/proprietary_exporters.rb

@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+module Splunk
+  module Otel
+    OUR_EXPORTERS_KEYS = ["jaeger-thrift-splunk"].freeze
+    private_constant :OUR_EXPORTERS_KEYS
+
+    # internal module for allowing our exporters to be set via ENV
+    module ExporterExtensions
+      def effective_splunk_jaeger_endpoint
+        return "https://ingest.#{ENV["SPLUNK_REALM"]}.signalfx.com/v1/trace" if ENV["SPLUNK_REALM"]
+        return ENV["OTEL_EXPORTER_JAEGER_ENDPOINT"] if ENV["OTEL_EXPORTER_JAEGER_ENDPOINT"]
+
+        "http://127.0.0.1:9080/v1/trace"
+      end
+
+      def wrapped_exporters_from_env
+        original_env_value = ENV.fetch("OTEL_TRACES_EXPORTER", "otlp")
+        exporters_keys = original_env_value.split(",").map(&:strip)
+        non_proprietary_exporters_keys = exporters_keys - OUR_EXPORTERS_KEYS
+
+        ENV["OTEL_TRACES_EXPORTER"] = non_proprietary_exporters_keys.join(",")
+        original_exporters = super
+        ENV["OTEL_TRACES_EXPORTER"] = original_env_value
+
+        original_exporters + proprietary_exporters(exporters_keys)
+      end
+
+      def proprietary_exporters(exporters_keys)
+        (exporters_keys & OUR_EXPORTERS_KEYS).map do |exporter_key|
+          case exporter_key
+          when "jaeger-thrift-splunk"
+            args = {
+              endpoint: effective_splunk_jaeger_endpoint
+            }
+            fetch_exporter_with_args("jaeger-thrift-splunk", "OpenTelemetry::Exporter::Jaeger::CollectorExporter",
+                                     **args)
+          end
+        end.compact
+      end
+
+      def fetch_exporter_with_args(name, class_name, **args)
+        # TODO: warn if jaeger exporter gem is not present
+        exporter = Kernel.const_get(class_name).new(**args)
+        OpenTelemetry::SDK::Trace::Export::BatchSpanProcessor.new exporter
+      rescue NameError
+        OpenTelemetry.logger.warn "The #{name} exporter cannot be configured" \
+                                  "- please add opentelemetry-exporter-#{name} to your Gemfile" \
+                                  ", spans will not be exported.."
+        nil
+      end
+    end
+  end
+end

test/splunk/otel/proprietary_exporters_test.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require "test_helper"
+require "opentelemetry/sdk"
+require "opentelemetry-exporter-jaeger"
+
+module Splunk
+  class OtelProprietaryExportersTest < Test::Unit::TestCase
+    def setup
+      with_env("OTEL_TRACES_EXPORTER" => "jaeger-thrift-splunk") do
+        Splunk::Otel.configure
+      end
+    end
+
+    def teardown
+      OpenTelemetry.tracer_provider.shutdown
+    end
+
+    test "check that jaeger exporter is present" do
+      processors = OpenTelemetry.tracer_provider.instance_variable_get("@span_processors")
+      exporter = processors[0].instance_variable_get("@exporter")
+      assert_instance_of OpenTelemetry::Exporter::Jaeger::CollectorExporter, exporter
+    end
+  end
+end

test/test_helper.rb

@@ -6,8 +6,7 @@
 require "simplecov-cobertura"
 SimpleCov.formatter = SimpleCov::Formatter::CoberturaFormatter
 
-$LOAD_PATH.unshift File.expand_path("../lib", __dir__)
-require "splunk/otel"
+require_relative "../lib/splunk/otel"
 
 require "test-unit"