separate context propagation otep

src/opentelemetry.erl

@@ -29,8 +29,14 @@
 -module(opentelemetry).
 
 -export([set_default_tracer/1,
+         set_default_context_manager/1,
+         get_context_manager/0,
          get_tracer/0,
          get_tracer/1,
+         set_http_extractor/1,
+         get_http_extractor/0,
+         set_http_injector/1,
+         get_http_injector/0,
          timestamp/0,
          links/1,
          link/4,
@@ -106,12 +112,42 @@
 set_default_tracer(Tracer) ->
     persistent_term:put({?MODULE, default_tracer}, Tracer).
 
+set_default_context_manager(ContextModule) ->
+    persistent_term:put({?MODULE, context_manager}, ContextModule).
+
+get_context_manager() ->
+    persistent_term:get({?MODULE, context_manager}, {ot_ctx_noop, []}).
+
 get_tracer() ->
     persistent_term:get({?MODULE, default_tracer}, {ot_tracer_noop, []}).
 
 get_tracer(_Name) ->
     persistent_term:get({?MODULE, default_tracer}, {ot_tracer_noop, []}).
 
+set_http_extractor(List) ->
+    Fun = fun(Headers) ->
+              lists:foldl(fun(Extract, ok) ->
+                              Extract(Headers),
+                              ok
+                          end, ok, List),
+              ok
+          end,
+    persistent_term:put({?MODULE, http_extractor}, Fun).
+
+set_http_injector(List) ->
+    Fun = fun(Headers) ->
+              lists:foldl(fun(Inject, HeadersAcc) ->
+                              Inject(HeadersAcc)
+                          end, Headers, List)
+          end,
+    persistent_term:put({?MODULE, http_injector}, Fun).
+
+get_http_extractor() ->
+    persistent_term:get({?MODULE, http_extractor}, fun(Headers) -> Headers end).
+
+get_http_injector() ->
+    persistent_term:get({?MODULE, http_injector}, fun(_Headers) -> ok end).
+
 -spec timestamp() -> integer().
 timestamp() ->
     erlang:system_time(nanosecond).

src/ot_baggage.erl

@@ -0,0 +1,73 @@
+%%%------------------------------------------------------------------------
+%% Copyright 2019, OpenTelemetry Authors
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%% http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% @doc
+%% @end
+%%%-------------------------------------------------------------------------
+-module(ot_baggage).
+
+-export([ctx_key/0,
+         set/2,
+         get/1,
+         remove/1,
+         clear/0,
+         get_http_propagators/0]).
+
+-type key() :: string().
+-type value() :: string().
+
+-export_type([key/0,
+              value/0]).
+
+-define(BAGGAGE_KEY, '$__ot_baggage_ctx_key').
+
+ctx_key() ->
+    ?BAGGAGE_KEY.
+
+-spec set(key(), value()) -> ok.
+set(Key, Value) ->
+    ot_ctx:set_value(?BAGGAGE_KEY, Key, Value).
+
+-spec get(key()) -> value().
+get(Key)->
+    ot_ctx:get_value(?BAGGAGE_KEY, Key).
+
+-spec remove(key()) -> ok.
+remove(Key) ->
+    ot_ctx:remove(?BAGGAGE_KEY, Key).
+
+-spec clear() -> ok.
+clear() ->
+    ot_ctx:clear(?BAGGAGE_KEY).
+
+-spec get_http_propagators() -> {ot_propagation:http_extractor(), ot_propagation:http_injector()}.
+get_http_propagators() ->
+    ToText = fun(_Headers, undefined) ->
+                     [];
+                (_Headers, Baggage) ->
+                     List = maps:fold(fun(Key, Value, Acc) ->
+                                              [[Key, "=", Value] | Acc]
+                                      end, [], Baggage),
+                     lists:join(",", List)
+             end,
+    FromText = fun(String, CurrentBaggage) ->
+                       Pairs = string:lexemes(String, [","]),
+                       lists:foldl(fun(Pair, Acc) ->
+                                           [Key, Pair] = string:split(Pair, "="),
+                                           Acc#{Key => {Pair, unlimited_propagation}}
+                                   end, CurrentBaggage, Pairs)
+               end,
+    Inject = ot_ctx:http_injector(?BAGGAGE_KEY, ToText),
+    Extract = ot_ctx:http_extractor(?BAGGAGE_KEY, FromText),
+    {Extract, Inject}.

src/ot_correlations.erl

@@ -0,0 +1,59 @@
+%%%------------------------------------------------------------------------
+%% Copyright 2019, OpenTelemetry Authors
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%% http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% @doc
+%% @end
+%%%-------------------------------------------------------------------------
+-module(ot_correlations).
+
+-export([ctx_key/0,
+         set/3,
+         get_http_propagators/0]).
+
+-type key() :: string().
+-type value() :: string().
+-type hop_limit() :: no_propagation | unlimited_propagation.
+
+-export_type([key/0,
+              value/0]).
+
+-define(CORRELATIONS_KEY, '$__ot_correlations_ctx_key').
+
+ctx_key() ->
+    ?CORRELATIONS_KEY.
+
+-spec set(key(), value(), hop_limit()) -> ok.
+set(Key, Value, HopLimit) ->
+    ot_ctx:set_value(?CORRELATIONS_KEY, Key, {Value, HopLimit}).
+
+-spec get_http_propagators() -> {ot_propagation:http_extractor(), ot_propagation:http_injector()}.
+get_http_propagators() ->
+    ToText = fun(_Headers, Correlations) ->
+                     List = maps:fold(fun(Key, {Value, unlimited_propagation}, Acc) ->
+                                              [[Key, "=", Value] | Acc];
+                                         (_Key, {_Value, no_propagation}, Acc) ->
+                                              Acc
+                               end, [], Correlations),
+                     lists:join(",", List)
+             end,
+    FromText = fun(String, CurrentCorrelations) ->
+                       Pairs = string:lexemes(String, [","]),
+                       lists:foldl(fun(Pair, Acc) ->
+                                           [Key, Pair] = string:split(Pair, "="),
+                                           Acc#{Key => {Pair, unlimited_propagation}}
+                                   end, CurrentCorrelations, Pairs)
+               end,
+    Inject = ot_ctx:http_injector(?CORRELATIONS_KEY, ToText),
+    Extract = ot_ctx:http_extractor(?CORRELATIONS_KEY, FromText),
+    {Extract, Inject}.

src/ot_ctx.erl

@@ -0,0 +1,144 @@
+%%%------------------------------------------------------------------------
+%% Copyright 2019, OpenTelemetry Authors
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%% http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% @doc
+%% @end
+%%%-------------------------------------------------------------------------
+-module(ot_ctx).
+
+-export([set_value/3,
+         get_value/2,
+         with_value/4,
+         with_value/5,
+         remove/2,
+         clear/1,
+         set_current/2,
+         get_current/1,
+         http_extractor/2,
+         http_injector/2,
+         http_extractor/3,
+         http_injector/3]).
+
+-type ctx() :: map().
+-type namespace() :: term().
+-type key() :: term().
+-type value() :: term().
+
+-callback set_value(namespace(), key(), value()) -> ok.
+-callback get_value(namespace(), key()) -> value() | undefined.
+-callback remove(namespace(), key()) -> ok.
+-callback clear(namespace()) -> ok.
+-callback set_current(namespace(), ctx()) -> ok.
+-callback get_current(namespace()) -> ctx().
+
+-export_type([ctx/0,
+              key/0,
+              value/0]).
+
+-spec set_value(namespace(), key(), value()) -> ok.
+set_value(Namespace, Key, Value) ->
+    set_value(opentelemetry:get_context_manager(), Namespace, Key, Value).
+
+-spec set_value(module(), namespace(), key(), value()) -> ok.
+set_value(CtxModule, Namespace, Key, Value) ->
+    CtxModule:set_value(Namespace, Key, Value).
+
+-spec get_value(namespace(), key()) -> value().
+get_value(Namespace, Key) ->
+    get_value(opentelemetry:get_context_manager(), Namespace, Key).
+
+-spec get_value(module(), namespace(), key()) -> value().
+get_value(Module, Namespace, Key) ->
+    Module:get_value(Namespace, Key).
+
+-spec with_value(namespace(), key(), value(), fun()) -> ok.
+with_value(Namespace, Key, Value, Fun) ->
+    with_value(opentelemetry:get_context_manager(), Namespace, Key, Value, Fun).
+
+-spec with_value(module(), namespace(), key(), value(), fun()) -> ok.
+with_value(CtxModule, Namespace, Key, Value, Fun) ->
+    PrevCtx = get_current(CtxModule, Namespace),
+    CtxModule:set_current(PrevCtx, Namespace, PrevCtx#{Key => Value}),
+    try
+        Fun()
+    after
+        set_current(CtxModule, Namespace, PrevCtx)
+    end.
+
+-spec remove(namespace(), key()) -> ok.
+remove(Namespace, Key) ->
+    remove(opentelemetry:get_context_manager(), Namespace, Key).
+
+-spec remove(module(), namespace(), key()) -> ok.
+remove(CtxModule, Namespace, Key) ->
+    CtxModule:remove(Namespace, Key).
+
+-spec clear(namespace()) -> ok.
+clear(Namespace) ->
+    clear(opentelemetry:get_context_manager(), Namespace).
+
+-spec clear(module(), namespace()) -> ok.
+clear(CtxModule, Namespace) ->
+    CtxModule:clear(Namespace).
+
+-spec set_current(namespace(), ctx()) -> ok.
+set_current(Namespace, Ctx) ->
+    set_current(opentelemetry:get_context_manager(), Namespace, Ctx).
+
+-spec set_current(module(), namespace(), ctx()) -> ok.
+set_current(CtxModule, Namespace, Ctx) ->
+    CtxModule:set_current(Namespace, Ctx).
+
+-spec get_current(namespace()) -> ctx().
+get_current(Namespace) ->
+    get_current(opentelemetry:get_context_manager(), Namespace).
+
+-spec get_current(module(), namespace()) -> ctx().
+get_current(CtxModule, Namespace) ->
+    CtxModule:get_current(Namespace).
+
+http_extractor(Namespace, FromText) ->
+    http_extractor_(opentelemetry:get_context_manager(), Namespace, FromText).
+
+http_extractor_(CtxModule, Namespace, FromText) ->
+    fun(_Headers) ->
+            String = "", %% Headers
+            New = FromText(String, CtxModule:get_current(Namespace)),
+            CtxModule:set_current(Namespace, New)
+    end.
+
+http_extractor(Namespace, Key, FromText) ->
+    http_extractor_(opentelemetry:get_context_manager(), Namespace, Key, FromText).
+
+http_extractor_(CtxModule, Namespace, Key, FromText) ->
+    fun(Headers) ->
+            New = FromText(Headers, CtxModule:get_value(Namespace, Key)),
+            CtxModule:set_value(Namespace, Key, New)
+    end.
+
+http_injector(Namespace, ToText) ->
+    http_injector_(opentelemetry:get_context_manager(), Namespace, ToText).
+
+http_injector_(CtxModule, Namespace, ToText) ->
+    fun(Headers) ->
+            Headers ++ ToText(Headers, CtxModule:get_current(Namespace))
+    end.
+
+http_injector(Namespace, Key, ToText) ->
+    http_injector_(opentelemetry:get_context_manager(), Namespace, Key, ToText).
+
+http_injector_(CtxModule, Namespace, Key, ToText) ->
+    fun(Headers) ->
+            Headers ++ ToText(Headers, CtxModule:get_value(Namespace, Key))
+    end.

src/ot_ctx_noop.erl

@@ -0,0 +1,51 @@
+%%%------------------------------------------------------------------------
+%% Copyright 2019, OpenTelemetry Authors
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%% http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% @doc
+%% @end
+%%%-------------------------------------------------------------------------
+-module(ot_ctx_noop).
+
+-behaviour(ot_ctx).
+
+-export([set_value/3,
+         get_value/2,
+         remove/2,
+         clear/1,
+         set_current/2,
+         get_current/1]).
+
+-spec set_value(ot_ctx:namespace(), ot_ctx:key(), ot_ctx:value()) -> ok.
+set_value(_Namespace, _Key, _Value) ->
+    ok.
+
+-spec get_value(ot_ctx:namespace(), ot_ctx:key()) -> ot_ctx:value().
+get_value(_Namespace, _Key) ->
+    undefined.
+
+-spec remove(ot_ctx:namespace(), ot_ctx:key()) -> ok.
+remove(_Namespace, _Key) ->
+    ok.
+
+-spec clear(ot_ctx:namespace()) -> ok.
+clear(_Namespace) ->
+    ok.
+
+-spec set_current(ot_ctx:namespace(), ot_ctx:ctx()) -> ok.
+set_current(_Namespace, _Ctx) ->
+    ok.
+
+-spec get_current(ot_ctx:namespace()) -> ot_ctx:ctx().
+get_current(_Namespace) ->
+    #{}.