lib/opentelemetry/trace.rb in opentelemetry-api-0.7.0 vs lib/opentelemetry/trace.rb in opentelemetry-api-0.8.0

@@ -7,35 +7,70 @@
 module OpenTelemetry
   # The Trace API allows recording a set of events, triggered as a result of a
   # single logical operation, consolidated across various components of an
   # application.
   module Trace
+    extend self
+
+    CURRENT_SPAN_KEY = Context.create_key('current-span')
+
+    private_constant :CURRENT_SPAN_KEY
+
     # An invalid trace identifier, a 16-byte string with all zero bytes.
     INVALID_TRACE_ID = ("\0" * 16).b
 
     # An invalid span identifier, an 8-byte string with all zero bytes.
     INVALID_SPAN_ID = ("\0" * 8).b
 
     # Generates a valid trace identifier, a 16-byte string with at least one
     # non-zero byte.
     #
     # @return [String] a valid trace ID.
-    def self.generate_trace_id
+    def generate_trace_id
       loop do
         id = Random::DEFAULT.bytes(16)
         return id unless id == INVALID_TRACE_ID
       end
     end
 
     # Generates a valid span identifier, an 8-byte string with at least one
     # non-zero byte.
     #
     # @return [String] a valid span ID.
-    def self.generate_span_id
+    def generate_span_id
       loop do
         id = Random::DEFAULT.bytes(8)
         return id unless id == INVALID_SPAN_ID
       end
+    end
+
+    # Returns the current span from the current or provided context
+    #
+    # @param [optional Context] context The context to lookup the current
+    #   {Span} from. Defaults to Context.current
+    def current_span(context = nil)
+      context ||= Context.current
+      context.value(CURRENT_SPAN_KEY) || Span::INVALID
+    end
+
+    # Returns a context containing the span, derived from the optional parent
+    # context, or the current context if one was not provided.
+    #
+    # @param [optional Context] context The context to use as the parent for
+    #   the returned context
+    def context_with_span(span, parent_context: Context.current)
+      parent_context.set_value(CURRENT_SPAN_KEY, span)
+    end
+
+    # Activates/deactivates the Span within the current Context, which makes the "current span"
+    # available implicitly.
+    #
+    # On exit, the Span that was active before calling this method will be reactivated.
+    #
+    # @param [Span] span the span to activate
+    # @yield [span, context] yields span and a context containing the span to the block.
+    def with_span(span)
+      Context.with_value(CURRENT_SPAN_KEY, span) { |c, s| yield s, c }
     end
   end
 end
 
 require 'opentelemetry/trace/link'