Add tracer_provider reference to tracer

The tracer carries a reference to the tracer_provider that initialized it to
begin supporting multiple tracer providers.

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

@@ -11,20 +11,22 @@ module Trace
       class Tracer < OpenTelemetry::Trace::Tracer
         attr_reader :name
         attr_reader :version
+        attr_reader :tracer_provider
 
         # @api private
         #
         # Returns a new {Tracer} instance.
         #
         # @param [String] name Instrumentation package name
         # @param [String] version Instrumentation package version
+        # @param [TracerProvider] tracer_provider TracerProvider that initialized the tracer
         #
         # @return [Tracer]
-        def initialize(name, version)
+        def initialize(name, version, tracer_provider)
           @name = name
           @version = version
           @instrumentation_library = InstrumentationLibrary.new(name, version)
-          @resource = OpenTelemetry.tracer_provider.resource
+          @tracer_provider = tracer_provider
         end
 
         def start_root_span(name, attributes: nil, links: nil, start_timestamp: nil, kind: nil)
@@ -41,7 +43,7 @@ def start_span(name, with_parent: nil, with_parent_context: nil, attributes: nil
           trace_id = parent_span_context&.trace_id
           trace_id ||= OpenTelemetry::Trace.generate_trace_id
           span_id = OpenTelemetry::Trace.generate_span_id
-          sampler = OpenTelemetry.tracer_provider.active_trace_config.sampler
+          sampler = tracer_provider.active_trace_config.sampler
           result = sampler.call(trace_id: trace_id, span_id: span_id, parent_context: parent_span_context, links: links, name: name, kind: kind, attributes: attributes)
 
           internal_create_span(result, name, kind, trace_id, span_id, parent_span_id, attributes, links, start_timestamp, tracestate)
@@ -50,13 +52,23 @@ def start_span(name, with_parent: nil, with_parent_context: nil, attributes: nil
         private
 
         def internal_create_span(result, name, kind, trace_id, span_id, parent_span_id, attributes, links, start_timestamp, tracestate) # rubocop:disable Metrics/AbcSize
-          if result.recording? && !OpenTelemetry.tracer_provider.stopped?
+          if result.recording? && !tracer_provider.stopped?
             trace_flags = result.sampled? ? OpenTelemetry::Trace::TraceFlags::SAMPLED : OpenTelemetry::Trace::TraceFlags::DEFAULT
             context = OpenTelemetry::Trace::SpanContext.new(trace_id: trace_id, trace_flags: trace_flags, tracestate: tracestate)
             attributes = attributes&.merge(result.attributes) || result.attributes
-            active_trace_config = OpenTelemetry.tracer_provider.active_trace_config
-            active_span_processor = OpenTelemetry.tracer_provider.active_span_processor
-            Span.new(context, name, kind, parent_span_id, active_trace_config, active_span_processor, attributes, links, start_timestamp || Time.now, @resource, @instrumentation_library)
+            Span.new(
+              context,
+              name,
+              kind,
+              parent_span_id,
+              tracer_provider.active_trace_config,
+              tracer_provider.active_span_processor,
+              attributes,
+              links,
+              start_timestamp || Time.now,
+              tracer_provider.resource,
+              @instrumentation_library
+            )
           else
             OpenTelemetry::Trace::Span.new(span_context: OpenTelemetry::Trace::SpanContext.new(trace_id: trace_id))
           end

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

@@ -38,7 +38,7 @@ def initialize(resource = OpenTelemetry::SDK::Resources::Resource.create)
         def tracer(name = nil, version = nil)
           name ||= ''
           version ||= ''
-          @mutex.synchronize { @registry[Key.new(name, version)] ||= Tracer.new(name, version) }
+          @mutex.synchronize { @registry[Key.new(name, version)] ||= Tracer.new(name, version, self) }
         end
 
         # Attempts to stop all the activity for this {Tracer}. Calls

sdk/test/opentelemetry/sdk/trace/tracer_test.rb

@@ -20,13 +20,19 @@
 
   describe '#name' do
     it 'reflects the name passed in' do
-      _(Tracer.new('component', 'semver:1.0').name).must_equal('component')
+      _(Tracer.new('component', 'semver:1.0', tracer_provider).name).must_equal('component')
     end
   end
 
   describe '#version' do
     it 'reflects the version passed in' do
-      _(Tracer.new('component', 'semver:1.0').version).must_equal('semver:1.0')
+      _(Tracer.new('component', 'semver:1.0', tracer_provider).version).must_equal('semver:1.0')
+    end
+  end
+
+  describe '#tracer_provider' do
+    it 'reflects the tracer_provider passed in' do
+      _(Tracer.new('component', 'semver:1.0', tracer_provider).tracer_provider).must_equal(tracer_provider)
     end
   end