otel resource implementation, including resources from OS vars

include/ot_resource.hrl

@@ -0,0 +1,72 @@
+%% if any `service' attribute is defined then
+%% `service.name' and `service.instance.id' are required
+
+%% The name of the telemetry library.
+-define(SERVICE_NAME, "service.name").
+%% The string ID of the service instance. MUST be unique for each instance of the same
+%% `service.namespace,service.name` pair.
+-define(SERVICE_INSTANCE, "service.instance.id").
+%% A namespace for `service.name`. A string value having a meaning that helps to distinguish a
+%% group of services,
+-define(SERVICE_NAMESPACE, "service.namespace").
+%% The version string of the service API or implementation.
+-define(SERVICE_VERSION, "service.version").
+
+%% Library attributes
+
+%% The name of the telemetry library.
+-define(LIBRARY_NAME, "library.name").
+%% The language of telemetry library and of the code instrumented with it.
+-define(LIBRARY_LANGUAGE, "library.language").
+%% The version string of the library.
+-define(LIBRARY_VERSION, "library.version").
+
+%% Container attributes
+
+%% Container name.
+-define(CONTAINER_NAME, "container.name").
+%% Name of the image the container was built on.
+-define(CONTAINER_IMAGE_NAME, "container.image.name").
+%% Container image tag.
+-define(CONTAINER_IMAGE_TAG, "container.image.tag").
+
+%% K8s attributes
+
+%% The name of the cluster that the pod is running in.
+-define(K8S_CLUSTER, "k8s.cluster.name").
+%% The name of the namespace that the pod is running in.
+-define(K8S_NAMESPACE, "k8s.namespace.name").
+%% The name of the pod.
+-define(K8S_POD, "k8s.pod.name").
+%% The name of the deployment.
+-define(K8S_DEPLOYMENT, "k8s.deployment.name").
+
+
+%% Host attributes
+
+%% Hostname of the host. It contains what the `hostname` command returns on the host machine.
+-define(HOST_HOSTNAME, "host.hostname").
+%% Unique host id. For Cloud this must be the instance_id assigned by the cloud provider.
+-define(HOST_ID, "host.id").
+%% Name of the host. It may contain what `hostname` returns on Unix systems, the fully qualified,
+%% or a name specified by the user.
+-define(HOST_NAME, "host.name").
+%% Type of host. For Cloud this must be the machine type.
+-define(HOST_TYPE, "host.type").
+%% Name of the VM image or OS install the host was instantiated from.
+-define(HOST_IMAGE_NAME, "host.image.name").
+%% VM image id. For Cloud, this value is from the provider.
+-define(HOST_IMAGE_ID, "host.image.id").
+%% The version string of the VM image.
+-define(HOST_IMAGE_VERSION, "host.image.version").
+
+%% Cloud attributes
+
+%% Name of the cloud provider.
+-define(CLOUD_PROVIDER, "cloud.provider").
+%% The cloud account id used to identify different entities.
+-define(CLOUD_ACCOUNT, "cloud.account.id").
+%% A specific geographical location where different entities can run.
+-define(CLOUD_REGION, "cloud.region").
+%% Zones are a sub set of the region connected through low-latency links.
+-define(CLOUD_ZONE, "cloud.zone").

include/ot_span.hrl

@@ -16,6 +16,8 @@
 %% @end
 %%%-------------------------------------------------------------------------
 
+%% Holds information about the instrumentation library specified when
+%% getting a Tracer from the TracerProvider.
 -record(library_resource, {name    :: atom() | undefined,
                            version :: string() | undefined}).
 

src/ot_resource.erl

@@ -0,0 +1,64 @@
+%%%------------------------------------------------------------------------
+%% 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_resource).
+
+-export([create/1,
+         merge/2]).
+
+-type key() :: io_lib:latin1_string().
+-type value() :: io_lib:latin1_string() | integer() | float() | boolean().
+-type resource() :: {resource, #{key() => value()}}.
+-opaque t() :: resource().
+
+-export_type([t/0]).
+
+-define(MAX_LENGTH, 255).
+
+%% verifies each key and value and drops any that don't pass verification
+-spec create(#{key() => value()}) -> t().
+create(Map) ->
+    {resource, maps:filter(fun(K, V) ->
+                                   %% TODO: log an info or debug message when dropping?
+                                   check_key(K) andalso check_value(V)
+                           end, Map)}.
+
+%% In case of collision the current, first argument, resource takes precedence.
+-spec merge(resource(), resource()) -> t().
+merge({resource, CurrentResource}, {resource, OtherResource}) ->
+    {resource, maps:merge(OtherResource, CurrentResource)}.
+
+%%
+
+%% all resource strings, key or value, must be latin1 with length less than 255
+check_string(S) ->
+    length(S) =< ?MAX_LENGTH andalso io_lib:deep_latin1_char_list(S).
+
+%% a resource key must be a non-empty latin1 string
+check_key(K) ->
+    is_list(K) andalso length(K) > 0 andalso check_string(K).
+
+%% a resource value can be a latin1 string, integer, float or boolean
+check_value(V) when is_integer(V) ;
+                    is_float(V) ;
+                    is_boolean(V) ->
+    true;
+check_value(V) when is_list(V) ->
+    check_string(V);
+check_value(_) ->
+    false.

src/ot_resource_env_var.erl

@@ -0,0 +1,44 @@
+%%%------------------------------------------------------------------------
+%% 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_resource_env_var).
+
+-export([get_resource/0]).
+
+-define(OS_ENV, "OTEL_RESOURCE_LABELS").
+-define(LABEL_LIST_SPLITTER, ",").
+-define(LABEL_KEY_VALUE_SPLITTER, "=").
+
+get_resource() ->
+    ot_resource:create(parse_resource_labels(os:getenv(?OS_ENV))).
+
+%%
+
+parse_resource_labels(false) ->
+    #{};
+parse_resource_labels(RawLabels) ->
+    Labels = string:split(RawLabels, ?LABEL_LIST_SPLITTER, all),
+    lists:foldl(fun(Label, Acc) ->
+                        case string:split(Label, ?LABEL_KEY_VALUE_SPLITTER, all) of
+                            [K, V] ->
+                                V1 = re:replace(string:trim(V), "^\"|\"$", "", [global, {return, list}]),
+                                Acc#{string:trim(K) => V1};
+                            _ ->
+                                Acc
+                        end
+                end, #{}, Labels).

src/ot_sampler.erl

@@ -39,14 +39,15 @@
                          opentelemetry:kind(),
                          opentelemetry:attributes(),
                          term()) -> sampling_result()), term()}.
+-opaque t() :: sampler().
 -export_type([sampling_result/0,
               sampling_decision/0,
-              sampler/0]).
+              t/0]).
 
 -define(MAX_VALUE, 9223372036854775807). %% 2^63 - 1
 -define(DEFAULT_PROBABILITY, 0.5).
 
--spec setup(atom() | module(), map()) -> sampler().
+-spec setup(atom() | module(), map()) -> t().
 setup(always_on, _Opts) ->
     {fun ?MODULE:always_on/8, []};
 setup(always_off, _Opts) ->

src/ot_tracer.hrl

@@ -4,9 +4,9 @@
                  ctx_module :: module(),
                  on_start_processors :: fun((opentelemetry:span()) -> opentelemetry:span()),
                  on_end_processors :: fun((opentelemetry:span()) -> boolean() | {error, term()}),
-                 sampler :: ot_sampler:sampler(),
+                 sampler :: ot_sampler:t(),
                  library_resource :: ot_tracer_server:library_resource() | undefined,
-                 resource :: term() | undefined}).
+                 resource :: ot_resource:t() | undefined}).
 -type tracer() :: #tracer{}.
 
 -record(tracer_ctx, {active :: opentelemetry:span_ctx() | undefined,

src/ot_tracer_server.erl

@@ -32,18 +32,21 @@
 -record(state, {tracer :: tracer(),
                 processors :: [module()],
                 deny_list :: [atom() | {atom(), string()}],
-                sampler :: ot_sampler:sampler()}).
+                sampler :: ot_sampler:t()}).
 
 init(Opts) ->
     {Sampler, SamplerOpts} = proplists:get_value(sampler, Opts, {always_on, #{}}),
     SamplerFun = ot_sampler:setup(Sampler, SamplerOpts),
     Processors = proplists:get_value(processors, Opts, []),
     DenyList = proplists:get_value(deny_list, Opts, []),
 
+    Resource = ot_resource_env_var:get_resource(),
+
     Tracer = #tracer{module=ot_tracer_default,
                      sampler=SamplerFun,
                      on_start_processors=on_start(Processors),
                      on_end_processors=on_end(Processors),
+                     resource=Resource,
                      span_module=ot_span_ets,
                      ctx_module=ot_ctx_pdict},
     opentelemetry:set_default_tracer({ot_tracer_default, Tracer}),

test/ot_resource_SUITE.erl

@@ -0,0 +1,40 @@
+-module(ot_resource_SUITE).
+
+-compile(export_all).
+
+-include_lib("stdlib/include/assert.hrl").
+-include_lib("common_test/include/ct.hrl").
+
+-include_lib("opentelemetry_api/include/opentelemetry.hrl").
+-include("ot_span.hrl").
+-include("ot_test_utils.hrl").
+-include("ot_tracer.hrl").
+
+all() ->
+    [os_env_resource].
+
+init_per_suite(Config) ->
+    os:putenv("OTEL_RESOURCE_LABELS", "service.name=cttest,service.version=1.1.1"),
+
+    application:load(opentelemetry),
+    application:set_env(opentelemetry, processors, [{ot_batch_processor, [{scheduled_delay_ms, 1}]}]),
+    {ok, _} = application:ensure_all_started(opentelemetry),
+    Config.
+
+end_per_suite(_Config) ->
+    _ = application:stop(opentelemetry).
+
+init_per_testcase(_, Config) ->
+    %% adds an exporter for a new table
+    %% spans will be exported to a separate table for each of the test cases
+    Tid = ets:new(exported_spans, [public, bag]),
+    ot_batch_processor:set_exporter(ot_exporter_tab, Tid),
+    [{tid, Tid} | Config].
+
+os_env_resource(_Config) ->
+    {_, Tracer} = opentelemetry:get_tracer(),
+
+    ?assertMatch({resource, #{"service.name" := "cttest",
+                              "service.version" := "1.1.1"}}, Tracer#tracer.resource),
+
+    ok.