fix!: refactor Baggage to remove Noop* (#800)

* fix!: refactor Baggage to remove Noop*

* Update api/lib/opentelemetry/baggage.rb

Co-authored-by: Andrew Hayworth <[email protected]>

Co-authored-by: Andrew Hayworth <[email protected]>

api/lib/opentelemetry.rb

@@ -24,7 +24,7 @@ module OpenTelemetry
   @mutex = Mutex.new
   @tracer_provider = Internal::ProxyTracerProvider.new
 
-  attr_writer :propagation, :baggage, :logger, :error_handler
+  attr_writer :propagation, :logger, :error_handler
 
   # @return [Object, Logger] configured Logger or a default STDOUT Logger.
   def logger
@@ -65,13 +65,6 @@ def tracer_provider
     @mutex.synchronize { @tracer_provider }
   end
 
-  # @return [Object, Baggage::NoopManager] registered
-  #   baggage manager or a default no-op implementation of the
-  #   manager.
-  def baggage
-    @baggage ||= Baggage::NoopManager.new
-  end
-
   # @return [Context::Propagation::Propagator] a propagator instance
   def propagation
     @propagation ||= Context::Propagation::NoopTextMapPropagator.new

api/lib/opentelemetry/baggage.rb

@@ -7,13 +7,103 @@
 require 'opentelemetry/baggage/propagation'
 require 'opentelemetry/baggage/builder'
 require 'opentelemetry/baggage/entry'
-require 'opentelemetry/baggage/manager'
-require 'opentelemetry/baggage/noop_builder'
-require 'opentelemetry/baggage/noop_manager'
 
 module OpenTelemetry
   # The Baggage module provides functionality to record and propagate
   # baggage in a distributed trace
   module Baggage
+    extend self
+
+    BAGGAGE_KEY = OpenTelemetry::Baggage::Propagation::ContextKeys.baggage_key
+    EMPTY_BAGGAGE = {}.freeze
+    private_constant(:BAGGAGE_KEY, :EMPTY_BAGGAGE)
+
+    # Used to chain modifications to baggage. The result is a
+    # context with an updated baggage. If only a single
+    # modification is being made to baggage, use the other
+    # methods on +Baggage+, if multiple modifications are being made, use
+    # this one.
+    #
+    # @param [optional Context] context The context to update with with new
+    #   modified baggage. Defaults to +Context.current+
+    # @return [Context]
+    def build(context: Context.current)
+      builder = Builder.new(baggage_for(context).dup)
+      yield builder
+      context.set_value(BAGGAGE_KEY, builder.entries)
+    end
+
+    # Returns a new context with empty baggage
+    #
+    # @param [optional Context] context Context to clear baggage from. Defaults
+    #   to +Context.current+
+    # @return [Context]
+    def clear(context: Context.current)
+      context.set_value(BAGGAGE_KEY, EMPTY_BAGGAGE)
+    end
+
+    # Returns the corresponding baggage.entry (or nil) for key
+    #
+    # @param [String] key The lookup key
+    # @param [optional Context] context The context from which to retrieve
+    #   the key.
+    #   Defaults to +Context.current+
+    # @return [String]
+    def value(key, context: Context.current)
+      baggage_for(context)[key]&.value
+    end
+
+    # Returns the baggage
+    #
+    # @param [optional Context] context The context from which to retrieve
+    #   the baggage.
+    #   Defaults to +Context.current+
+    # @return [Hash]
+    def values(context: Context.current)
+      baggage_for(context).transform_values(&:value)
+    end
+
+    # @api private
+    def raw_entries(context: Context.current)
+      baggage_for(context).dup.freeze
+    end
+
+    # Returns a new context with new key-value pair
+    #
+    # @param [String] key The key to store this value under
+    # @param [String] value String value to be stored under key
+    # @param [optional String] metadata This is here to store properties
+    #   received from other W3C Baggage impelmentations but is not exposed in
+    #   OpenTelemetry. This is condsidered private API and not for use by
+    #   end-users.
+    # @param [optional Context] context The context to update with new
+    #   value. Defaults to +Context.current+
+    # @return [Context]
+    def set_value(key, value, metadata: nil, context: Context.current)
+      new_baggage = baggage_for(context).dup
+      new_baggage[key] = Entry.new(value, metadata)
+      context.set_value(BAGGAGE_KEY, new_baggage)
+    end
+
+    # Returns a new context with value at key removed
+    #
+    # @param [String] key The key to remove
+    # @param [optional Context] context The context to remove baggage
+    #   from. Defaults to +Context.current+
+    # @return [Context]
+    def remove_value(key, context: Context.current)
+      baggage = baggage_for(context)
+      return context unless baggage.key?(key)
+
+      new_baggage = baggage.dup
+      new_baggage.delete(key)
+      context.set_value(BAGGAGE_KEY, new_baggage)
+    end
+
+    private
+
+    def baggage_for(context)
+      context.value(BAGGAGE_KEY) || EMPTY_BAGGAGE
+    end
   end
 end

api/lib/opentelemetry/baggage/propagation/text_map_propagator.rb

@@ -29,7 +29,7 @@ class TextMapPropagator
         #   will be used to write context into the carrier, otherwise the default
         #   text map setter will be used.
         def inject(carrier, context: Context.current, setter: Context::Propagation.text_map_setter)
-          baggage = OpenTelemetry.baggage.raw_entries(context: context)
+          baggage = OpenTelemetry::Baggage.raw_entries(context: context)
 
           return if baggage.nil? || baggage.empty?
 
@@ -55,7 +55,7 @@ def extract(carrier, context: Context.current, getter: Context::Propagation.text
 
           entries = header.gsub(/\s/, '').split(',')
 
-          OpenTelemetry.baggage.build(context: context) do |builder|
+          OpenTelemetry::Baggage.build(context: context) do |builder|
             entries.each do |entry|
               # Note metadata is currently unused in OpenTelemetry, but is part
               # the W3C spec where it's referred to as properties. We preserve