rework propagators to use a composite propagator

instead of propagators always being a list that are run in order
this PR requires a composite propagator be created if a multiple
propagators are to be used.

apps/opentelemetry/test/otel_propagation_SUITE.erl

@@ -127,8 +127,7 @@ override_propagators(_Config) ->
     %% drop baggage with bad value
     otel_baggage:set(<<"key-3">>, value3),
 
-    Headers = otel_propagator_text_map:inject([{<<"existing-header">>, <<"I exist">>}],
-                                              #{propagators => [otel_propagator_baggage]}),
+    Headers = otel_propagator_text_map:inject({otel_propagator_baggage, []}, [{<<"existing-header">>, <<"I exist">>}]),
 
     %% the manually set propagators does not include trace_context or b3
     %% so header must only have the existing-header and the baggage
@@ -152,7 +151,7 @@ override_propagators(_Config) ->
 
     %% make header keys uppercase to validate the extractor is case insensitive
     BinaryHeaders = [{string:uppercase(Key), iolist_to_binary(Value)} || {Key, Value} <- Headers],
-    otel_propagator_text_map:extract(BinaryHeaders, #{propagators => [otel_propagator_baggage]}),
+    otel_propagator_text_map:extract({otel_propagator_baggage, []}, BinaryHeaders),
 
     ?assertEqual(#{<<"key-1">> => {<<"value=1">>, []},
                    <<"key-2">> => {<<"value-2">>, [<<"metadata">>, {<<"md-k-1">>, <<"md-v-1">>}]}},

apps/opentelemetry_api/lib/open_telemetry/baggage.ex

@@ -13,5 +13,4 @@ defmodule OpenTelemetry.Baggage do
   defdelegate get_all(ctx), to: :otel_baggage
   defdelegate clear(), to: :otel_baggage
   defdelegate clear(ctx), to: :otel_baggage
-  defdelegate get_text_map_propagators(), to: :otel_baggage
 end

apps/opentelemetry_api/src/opentelemetry.erl

@@ -36,9 +36,11 @@
          get_tracer/1,
          set_text_map_propagators/1,
          set_text_map_extractors/1,
-         get_text_map_extractors/0,
+         set_text_map_extractor/1,
+         get_text_map_extractor/0,
          set_text_map_injectors/1,
-         get_text_map_injectors/0,
+         set_text_map_injector/1,
+         get_text_map_injector/0,
          timestamp/0,
          timestamp_to_nano/1,
          convert_timestamp/2,
@@ -153,28 +155,36 @@ get_tracer(Name) ->
 %% setting the propagators is the same as setting the same list for
 %% injectors and extractors
 set_text_map_propagators(List) when is_list(List) ->
-    set_text_map_injectors(List),
-    set_text_map_extractors(List);
+    CompositeInjector = otel_propagator_text_map_composite:create(List),
+    CompositeExtractor = otel_propagator_text_map_composite:create(List),
+    set_text_map_injector(CompositeInjector),
+    set_text_map_extractor(CompositeExtractor);
 set_text_map_propagators(_) ->
     ok.
 
 set_text_map_extractors(List) when is_list(List) ->
-    ParsedList = otel_propagator:builtins_to_modules(List),
-    persistent_term:put({?MODULE, text_map_extractors}, ParsedList);
+    CompositeExtractor = otel_propagator_text_map_composite:create(List),
+    set_text_map_extractor(CompositeExtractor);
 set_text_map_extractors(_) ->
     ok.
 
+set_text_map_extractor(Propagator) ->
+    persistent_term:put({?MODULE, text_map_extractor}, Propagator).
+
 set_text_map_injectors(List) when is_list(List) ->
-    ParsedList = otel_propagator:builtins_to_modules(List),
-    persistent_term:put({?MODULE, text_map_injectors}, ParsedList);
+    CompositeInjector = otel_propagator_text_map_composite:create(List),
+    set_text_map_extractor(CompositeInjector);
 set_text_map_injectors(_) ->
     ok.
 
-get_text_map_extractors() ->
-    persistent_term:get({?MODULE, text_map_extractors}, []).
+set_text_map_injector(Propagator) ->
+    persistent_term:put({?MODULE, text_map_injector}, Propagator).
+
+get_text_map_extractor() ->
+    persistent_term:get({?MODULE, text_map_extractor}, otel_propagator_text_map_noop).
 
-get_text_map_injectors() ->
-    persistent_term:get({?MODULE, text_map_injectors}, []).
+get_text_map_injector() ->
+    persistent_term:get({?MODULE, text_map_injector}, otel_propagator_text_map_noop).
 
 %% @doc A monotonically increasing time provided by the Erlang runtime system in the native time unit.
 %% This value is the most accurate and precise timestamp available from the Erlang runtime and

apps/opentelemetry_api/src/otel_propagator.erl

@@ -35,19 +35,13 @@
          builtin_to_module/1]).
 
 %% Sets a value into a carrier
--callback inject(carrier()) -> carrier().
--callback inject(carrier(), propagator_options()) -> carrier().
--callback inject_from(otel_ctx:t(), carrier()) -> carrier().
--callback inject_from(otel_ctx:t(), carrier(), propagator_options()) -> carrier().
+-callback inject(t(), carrier()) -> carrier().
+-callback inject_from(otel_ctx:t(), t(), carrier()) -> carrier().
 %% extracts values from a carrier and sets them in the context
--callback extract(carrier()) -> otel_ctx:t().
--callback extract(carrier(), propagator_options()) -> otel_ctx:t().
--callback extract_to(otel_ctx:t(), carrier()) -> otel_ctx:t().
--callback extract_to(otel_ctx:t(), carrier(), propagator_options()) -> otel_ctx:t().
+-callback extract(t(), carrier()) -> otel_ctx:t().
+-callback extract_to(otel_ctx:t(), t(), carrier()) -> otel_ctx:t().
 
--type propagator_options() :: #{propagators => [t()]}.
-
--type t() :: builtin() | module().
+-type t() :: builtin() | module() | {module(), term()}.
 
 -type builtin() :: trace_context | tracecontext | b3. %% multib3 | jaeger
 
@@ -78,5 +72,7 @@ builtin_to_module(b3) ->
 %%     otel_propagator_multib3;
 %% builtin_to_module(jaeger) ->
 %%     otel_propagator_jaeger;
-builtin_to_module(Module) ->
-    Module.
+builtin_to_module(Module) when is_atom(Module) ->
+    Module;
+builtin_to_module(Propagator) ->
+    Propagator.

apps/opentelemetry_api/src/otel_propagator_b3.erl

@@ -53,9 +53,9 @@
 
 -behaviour(otel_propagator_text_map).
 
--export([fields/0,
-         inject/3,
-         extract/4]).
+-export([fields/1,
+         inject/4,
+         extract/5]).
 
 -include("opentelemetry.hrl").
 
@@ -65,10 +65,10 @@
 
 -define(B3_IS_SAMPLED(S), S =:= "1" orelse S =:= <<"1">> orelse S =:= "true" orelse S =:= <<"true">>).
 
-fields() ->
+fields(_) ->
     [?B3_TRACE_ID, ?B3_SPAN_ID, ?B3_SAMPLED].
 
-inject(Ctx, Carrier, CarrierSet) ->
+inject(Ctx, Carrier, CarrierSet, _Options) ->
     case otel_tracer:current_span_ctx(Ctx) of
         #span_ctx{trace_id=TraceId,
                   span_id=SpanId,
@@ -83,7 +83,7 @@ inject(Ctx, Carrier, CarrierSet) ->
             Carrier
     end.
 
-extract(Ctx, Carrier, _CarrierKeysFun, CarrierGet) ->
+extract(Ctx, Carrier, _CarrierKeysFun, CarrierGet, _Options) ->
     try
         TraceId = trace_id(Carrier, CarrierGet),
         SpanId = span_id(Carrier, CarrierGet),

apps/opentelemetry_api/src/otel_propagator_baggage.erl

@@ -31,9 +31,9 @@
 
 -behaviour(otel_propagator_text_map).
 
--export([fields/0,
-         inject/3,
-         extract/4]).
+-export([fields/1,
+         inject/4,
+         extract/5]).
 
 -include("opentelemetry.hrl").
 
@@ -50,10 +50,10 @@
 
 -define(BAGGAGE_HEADER, <<"baggage">>).
 
-fields() ->
+fields(_) ->
     [?BAGGAGE_HEADER].
 
-inject(Ctx, Carrier, CarrierSet) ->
+inject(Ctx, Carrier, CarrierSet, _Options) ->
     Baggage = otel_baggage:get_all(Ctx),
     case maps:fold(fun(Key, Value, Acc) ->
                            [$,, [encode_key(Key), "=", encode_value(Value)] | Acc]
@@ -64,7 +64,7 @@ inject(Ctx, Carrier, CarrierSet) ->
             Carrier
     end.
 
-extract(Ctx, Carrier, _CarrierKeysFun, CarrierGet) ->
+extract(Ctx, Carrier, _CarrierKeysFun, CarrierGet, _Options) ->
     case CarrierGet(?BAGGAGE_HEADER, Carrier) of
         undefined ->
             Ctx;

apps/opentelemetry_api/src/otel_propagator_text_map.erl

@@ -57,14 +57,19 @@
 
 -behaviour(otel_propagator).
 
--export([inject/1,
+-export([fields/1,
+         inject/1,
          inject/2,
+         inject/3,
          inject_from/2,
          inject_from/3,
+         inject_from/4,
          extract/1,
          extract/2,
+         extract/4,
          extract_to/2,
-         extract_to/3]).
+         extract_to/3,
+         extract_to/5]).
 
 -export([default_carrier_get/2,
          default_carrier_set/3,
@@ -73,13 +78,16 @@
 -include_lib("kernel/include/logger.hrl").
 
 %% Sets a value into a carrier
--callback inject(otel_ctx:t(), otel_propagator:carrier(), carrier_set()) -> otel_propagator:carrier().
+-callback inject(otel_ctx:t(), otel_propagator:carrier(), carrier_set(), propagator_options()) -> otel_propagator:carrier().
 
 %% Extracts values from a carrier and sets them in the context
--callback extract(otel_ctx:t(), otel_propagator:carrier(), carrier_keys(), carrier_get()) -> term().
+-callback extract(otel_ctx:t(), otel_propagator:carrier(), carrier_keys(), carrier_get(), propagator_options()) -> term().
 
 %% Returns all the keys the propagator sets with `inject'
--callback fields() -> [field_key()].
+-callback fields(propagator_options()) -> [field_key()].
+
+%% a textmap propagator can have any term associated with it
+-type propagator_options() :: term().
 
 -type field_key() :: unicode:latin1_binary().
 -type field_value() :: unicode:latin1_binary().
@@ -93,89 +101,76 @@
 
 -type default_text_map_carrier() :: [{unicode:latin1_binary(), unicode:latin1_binary()}].
 
--type inject_options() :: #{carrier_set_fun => carrier_set(),
-                            propagators => [otel_propagator:t()]}.
+%% 2-tuple form is a textmap propagator with options
+%% an empty list is passed for options if the propagator is a module with no options
+-type t() :: module() | {module(), propagator_options()}.
+
+-export_type([t/0]).
 
--type extract_options() :: #{carrier_get_fun => carrier_get(),
-                             carrier_keys_fun => carrier_keys(),
-                             propagators => [otel_propagator:t()]}.
--export_type([]).
+-spec fields(otel_propagator:t()) -> [field_key()].
+fields(Propagator) when is_atom(Propagator) ->
+    Propagator:fields([]);
+fields({Module, Options}) ->
+    Module:fields(Options).
 
 -spec inject(otel_propagator:carrier()) -> otel_propagator:carrier().
 inject(Carrier) ->
-    inject(Carrier, #{}).
+    Propagator = opentelemetry:get_text_map_injector(),
+    inject(Propagator, Carrier, fun default_carrier_set/3).
+
+-spec inject(otel_propagator:t(), otel_propagator:carrier()) -> otel_propagator:carrier().
+inject(Propagator, Carrier) ->
+    inject(Propagator, Carrier, fun default_carrier_set/3).
 
--spec inject(otel_propagator:carrier(), inject_options()) -> otel_propagator:carrier().
-inject(Carrier, InjectOptions) ->
+-spec inject(otel_propagator:t(), otel_propagator:carrier(), fun()) -> otel_propagator:carrier().
+inject(Propagator, Carrier, CarrierSetFun) ->
     Context = otel_ctx:get_current(),
-    inject_from(Context, Carrier, InjectOptions).
+    inject_from(Context, Propagator, Carrier, CarrierSetFun).
 
 -spec inject_from(otel_ctx:t(), otel_propagator:carrier()) -> otel_propagator:carrier().
 inject_from(Context, Carrier) ->
-    inject_from(Context, Carrier, #{}).
+    Propagator = opentelemetry:get_text_map_injector(),
+    inject_from(Context, Propagator, Carrier, fun default_carrier_set/3).
 
--spec inject_from(otel_ctx:t(), otel_propagator:carrier(), inject_options()) -> otel_propagator:carrier().
-inject_from(Context, Carrier, InjectOptions) when is_map(InjectOptions)->
-    Injectors = maps:get(propagators, InjectOptions, opentelemetry:get_text_map_injectors()),
-    CarrierSetFun = maps:get(carrier_set_fun, InjectOptions, fun ?MODULE:default_carrier_set/3),
-    run_injectors(Context, Injectors, Carrier, CarrierSetFun);
-inject_from(_Context, Carrier, InjectOptions) ->
-    ?LOG_INFO("inject failed. InjectOptions must be a map but instead got: ~p", [InjectOptions]),
-    Carrier.
+-spec inject_from(otel_ctx:t(), otel_propagator:t(), otel_propagator:carrier()) -> otel_propagator:carrier().
+inject_from(Context, Propagator, Carrier) ->
+    inject_from(Context, Propagator, Carrier, fun default_carrier_set/3).
+
+-spec inject_from(otel_ctx:t(), otel_propagator:t(), otel_propagator:carrier(), fun()) -> otel_propagator:carrier().
+inject_from(Context, Module, Carrier, CarrierSetFun) when is_atom(Module) ->
+     Module:inject(Context, Carrier, CarrierSetFun, []);
+inject_from(Context, {Module, Options}, Carrier, CarrierSetFun) ->
+     Module:inject(Context, Carrier, CarrierSetFun, Options).
 
 -spec extract(otel_propagator:carrier()) -> otel_ctx:t().
 extract(Carrier) ->
-    extract(Carrier, #{}).
+    Propagator = opentelemetry:get_text_map_extractor(),
+    extract(Propagator, Carrier, fun default_carrier_keys/1, fun default_carrier_get/2).
+
+-spec extract(otel_propagator:t(), otel_propagator:carrier()) -> otel_ctx:t().
+extract(Propagator, Carrier) ->
+    extract(Propagator, Carrier, fun default_carrier_keys/1, fun default_carrier_get/2).
 
--spec extract(otel_propagator:carrier(), extract_options()) -> otel_ctx:t().
-extract(Carrier, ExtractOptions) ->
+-spec extract(otel_propagator:t(), otel_propagator:carrier(), fun(), fun()) -> otel_ctx:t().
+extract(Propagator, Carrier, CarrierKeysFun, CarrierGetFun) ->
     Context = otel_ctx:get_current(),
-    Context1 = extract_to(Context, Carrier, ExtractOptions),
+    Context1 = extract_to(Context, Propagator, Carrier, CarrierKeysFun, CarrierGetFun),
     otel_ctx:attach(Context1).
 
 -spec extract_to(otel_ctx:t(), otel_propagator:carrier()) -> otel_ctx:t().
 extract_to(Context, Carrier) ->
-    extract_to(Context, Carrier, #{}).
-
--spec extract_to(otel_ctx:t(), otel_propagator:carrier(), extract_options()) -> otel_ctx:t().
-extract_to(Context, Carrier, ExtractOptions) when is_map(ExtractOptions) ->
-    Extractors = maps:get(propagators, ExtractOptions, opentelemetry:get_text_map_extractors()),
-    CarrierKeysFun = maps:get(carrier_keys_fun, ExtractOptions, fun ?MODULE:default_carrier_keys/1),
-    CarrierGetFun = maps:get(carrier_get_fun, ExtractOptions, fun ?MODULE:default_carrier_get/2),
-    run_extractors(Context, Extractors, Carrier, CarrierKeysFun, CarrierGetFun);
-extract_to(Context, _Carrier, ExtractOptions) ->
-    ?LOG_INFO("extract failed. ExtractOptions must be a map but instead got: ~p", [ExtractOptions]),
-    Context.
-
-run_extractors(Context, Extractors, Carrier, CarrierKeysFun, CarrierGetFun) when is_list(Extractors) ->
-    lists:foldl(fun(Extract, ContextAcc) ->
-                        try Extract:extract(ContextAcc, Carrier, CarrierKeysFun, CarrierGetFun)
-                        catch
-                            C:E:S ->
-                                ?LOG_INFO("text map propagator failed to extract from carrier",
-                                          #{extractor => Extract, carrier => Carrier,
-                                            class => C, exception => E, stacktrace => S}),
-                                ContextAcc
-                        end
-                end, Context, otel_propagator:builtins_to_modules(Extractors));
-run_extractors(Context, Extractors, _, _, _) ->
-    ?LOG_INFO("extract failed. Extractors must be a list but instead got: ~p", [Extractors]),
-    Context.
-
-run_injectors(Context, Injectors, Carrier, Setter) when is_list(Injectors) ->
-    lists:foldl(fun(Inject, CarrierAcc) ->
-                        try Inject:inject(Context, CarrierAcc, Setter)
-                        catch
-                            C:E:S ->
-                                ?LOG_INFO("text map propagator failed to inject to carrier",
-                                          #{injector => Inject, carrier => CarrierAcc,
-                                            class => C, exception => E, stacktrace => S}),
-                                CarrierAcc
-                        end
-                end, Carrier, otel_propagator:builtins_to_modules(Injectors));
-run_injectors(_, Injectors, Carrier, _) ->
-    ?LOG_INFO("inject failed. Injectors must be a list but instead got: ~p", [Injectors]),
-    Carrier.
+    Propagator = opentelemetry:get_text_map_extractor(),
+    extract_to(Context, Propagator, Carrier, fun default_carrier_keys/1, fun default_carrier_get/2).
+
+-spec extract_to(otel_ctx:t(), otel_propagator:t(), otel_propagator:carrier()) -> otel_ctx:t().
+extract_to(Context, Propagator, Carrier) ->
+    extract_to(Context, Propagator, Carrier, fun default_carrier_keys/1, fun default_carrier_get/2).
+
+-spec extract_to(otel_ctx:t(), otel_propagator:t(), otel_propagator:carrier(), fun(), fun()) -> otel_ctx:t().
+extract_to(Context, Module, Carrier, CarrierKeysFun, CarrierGetFun) when is_atom(Module) ->
+    Module:extract(Context, Carrier, CarrierKeysFun, CarrierGetFun, []);
+extract_to(Context, {Module, Options}, Carrier, CarrierKeysFun, CarrierGetFun) ->
+    Module:extract(Context, Carrier, CarrierKeysFun, CarrierGetFun, Options).
 
 %% case-insensitive finding of a key string in a list of ASCII strings
 %% if there are multiple entries in the list for the same key the values