[WeCall Opentracing] Basic support for Jager / OpenTracing

lib/we/call.rb

@@ -15,6 +15,7 @@ class << self
     end
 
     def self.configuration
+      # potentially add in tracer here as param
       @configuration ||= Configuration.new
     end
 

lib/we/call/connection.rb

@@ -1,5 +1,10 @@
 require 'typhoeus/adapters/faraday'
 
+require 'opentracing'
+require 'faraday/tracer'
+require 'rack/tracer'
+require 'jaeger/client'
+
 module We
   module Call
     module Connection
@@ -40,18 +45,20 @@ def get_adapter
       # @param [String] app
       # @param [String] env
       # @yieldparam [Faraday::Connection] Faraday connection object is yielded to a block
-      def new(host:, timeout: nil, open_timeout: OPEN_TIMEOUT, app: guess_app, env: guess_env, &block)
+      def new(host:, timeout: nil, open_timeout: OPEN_TIMEOUT, app: guess_app, env: guess_env, active_span: guess_span, &block)
         @host = host
         @app = app or raise_missing_app!
         @env = env or raise_missing_env!
         @timeout = timeout or raise_missing_timeout!
         @open_timeout = open_timeout or raise_missing_open_timeout!
+        @active_span = active_span
+
         create(&block)
       end
 
       private
 
-      attr_reader :app, :env, :host, :timeout, :open_timeout
+      attr_reader :app, :env, :host, :timeout, :open_timeout, :active_span
 
       # @return [Faraday::Connection] Preconfigured Faraday Connection object, for hitting get, post, etc.
       def create
@@ -63,12 +70,14 @@ def create
           config.app_env_header   => env,
         }
 
-        request = {
+        options = {
           timeout:      timeout,
           open_timeout: open_timeout
         }
 
-        Faraday.new(host, builder: builder, headers: headers, request: request) do |faraday|
+        Faraday.new(host, builder: builder, headers: headers, request: options) do |faraday|
+          faraday.use Faraday::Tracer, span: active_span
+
           if config.detect_deprecations
             faraday.response :sunset, setup_sunset_middleware(faraday)
           end
@@ -132,6 +141,11 @@ def guess_app
         ENV['APP_NAME'] || rails_app_name
       end
 
+      def guess_span
+        return rails_app_env['rack.span'] if rails_app_env
+        nil
+      end
+
       def rails_app_env
         ::Rails.env if (defined? ::Rails)
       end

lib/we/call/version.rb

@@ -1,5 +1,5 @@
 module We
   module Call
-    VERSION = "0.8.0"
+    VERSION = "0.9.a"
   end
 end

spec/unit/we/call/connection_spec.rb

@@ -1,7 +1,7 @@
 require "spec_helper"
 
 RSpec.describe We::Call::Connection do
-  DEFAULT_MIDDLEWARES = [FaradayMiddleware::Gzip, Faraday::Sunset]
+  DEFAULT_MIDDLEWARES = [FaradayMiddleware::Gzip, Faraday::Sunset, Faraday::Tracer]
 
   describe '#initialize' do
     context 'when host is missing' do
@@ -102,6 +102,32 @@
       end
     end
 
+    context 'when active_span needs to be guessed' do
+      subject { described_class.new(host: 'http://foo.com', app: 'foo', env: env, timeout: 5, open_timeout: 10) }
+
+      context 'rack.span is present' do
+        let(:env) do
+          {
+            'test' => {
+              'rack.span' => 'some_span'
+            }
+          }
+        end
+
+        it 'contains X-App-Name header' do
+          expect(subject.headers['X-App-Env']['test']['rack.span']).to eq('some_span')
+        end
+      end
+
+      context 'rack.span is not present' do
+        let(:env) { 'test' }
+
+        it 'sets active_span to nil if rack.span is not present' do
+          expect(subject.headers['X-App-Env']['test']['rack.span']).to be_nil
+        end
+      end
+    end
+
     context 'with custom block' do
       subject do
         described_class.new(**valid_arguments) do |faraday|

we-call.gemspec

@@ -23,7 +23,10 @@ Gem::Specification.new do |spec|
   spec.add_dependency "typhoeus", "~> 1.3"
   spec.add_dependency "faraday", ">= 0.9.0", "< 1"
   spec.add_dependency "faraday_middleware", '~> 0.10'
-  spec.add_dependency "faraday-sunset", '~> 0.2'
+  spec.add_dependency "faraday-sunset", "~> 0.2"
+  spec.add_dependency 'faraday-tracer', "~> 0.6.0"
+  spec.add_dependency 'jaeger-client'
+  spec.add_dependency 'rack-tracer'
 
   spec.add_development_dependency "appraisal", "~> 2.0"
   spec.add_development_dependency "coveralls", '~> 0.7'