Populate resource to OTLP proto data

.markdownlintignore

@@ -1,2 +1,3 @@
 third_party/**
 tools/**
+examples/otlp/README.md

CHANGELOG.md

@@ -15,6 +15,8 @@ Increment the:
 
 ## [Unreleased]
 
+* [EXPORTER] Populate resource to OTLP proto data ([#758](https://github.com/open-telemetry/opentelemetry-cpp/pull/758))
+
 ## [0.6.0] 2021-05-11
 
 * [EXPORTER] Add Jaeger exporter ([#534](https://github.com/open-telemetry/opentelemetry-cpp/pull/534))

examples/otlp/README.md

@@ -10,36 +10,34 @@ SDK](https://github.com/open-telemetry/opentelemetry-cpp). The application then
 calls a `foo_library` which has been instrumented using the [OpenTelemetry
 API](https://github.com/open-telemetry/opentelemetry-cpp/tree/main/api).
 
-To enable TLS authentication for OTLP grpc exporter, SslCredentials can be used by
-specifying the path to client certificate pem file, or the string containing this certificate via OtlpExporterOptions. The path to such a
-.pem file can be provided as a command-line argument alongwith the collector endpoint
-to the main binary invocation above.
+To enable TLS authentication for OTLP grpc exporter, SslCredentials can be used
+by specifying the path to client certificate pem file, or the string containing
+this certificate via OtlpExporterOptions. The path to such a .pem file can be
+provided as a command-line argument alongwith the collector endpoint to the main
+binary invocation above.
 
 Resulting spans are exported to the **OpenTelemetry Collector** using the OTLP
 exporter. The OpenTelemetry Collector can be configured to export to other
 backends (see list of [supported
 backends](https://github.com/open-telemetry/opentelemetry-collector/blob/main/exporter/README.md)).
 
-For instructions on downloading and running the OpenTelemetry Collector, see
-[Getting Started](https://opentelemetry.io/docs/collector/about/).
-
-Here is an example of a Collector `config.yaml` file that can be used to export
-to [Zipkin](https://zipkin.io/) via the Collector using the OTLP exporter:
-
-```yml
-receivers:
-  otlp:
-    protocols:
-      grpc:
-        endpoint: localhost:4317
-exporters:
-  zipkin:
-    endpoint: "http://localhost:9411/api/v2/spans"
-service:
-  pipelines:
-    traces:
-      receivers: [otlp]
-      exporters: [zipkin]
+Follow below command to run the **OpenTelemetry Collector** with OTLP receiver
+in docker which dumps the received data into console. See [Getting
+Started](https://opentelemetry.io/docs/collector/about/) for more information.
+
+Open a terminal window at the root directory of this repo and launch the
+OpenTelemetry Collector with an OTLP receiver by running:
+
+- On Unix based systems use:
+
+```console
+docker run --rm -it -p 4317:4317 -v $(pwd)/examples/otlp:/cfg otel/opentelemetry-collector:0.19.0 --config=/cfg/opentelemetry-collector-config/config.dev.yaml
+```
+
+- On Windows use:
+
+```console
+docker run --rm -it -p 4317:4317 -v "%cd%/examples/otlp":/cfg otel/opentelemetry-collector:0.19.0 --config=/cfg/opentelemetry-collector-config/config.dev.yaml
 ```
 
 Note that the OTLP exporter connects to the Collector at `localhost:4317` by

examples/otlp/opentelemetry-collector-config/config.dev.yaml

@@ -0,0 +1,15 @@
+exporters:
+  logging:
+    loglevel: DEBUG
+receivers:
+  otlp:
+    protocols:
+      grpc:
+        endpoint: 0.0.0.0:4317
+service:
+  pipelines:
+    traces:
+      receivers:
+      - otlp
+      exporters:
+      - logging

exporters/otlp/include/opentelemetry/exporters/otlp/recordable.h

@@ -53,7 +53,7 @@ class Recordable final : public sdk::trace::Recordable
 
 private:
   proto::trace::v1::Span span_;
-  const opentelemetry::sdk::resource::Resource *resource_;
+  const opentelemetry::sdk::resource::Resource *resource_ = nullptr;
 };
 }  // namespace otlp
 }  // namespace exporter

exporters/otlp/src/otlp_exporter.cc

@@ -28,8 +28,13 @@ void PopulateRequest(const nostd::span<std::unique_ptr<sdk::trace::Recordable>>
   for (auto &recordable : spans)
   {
     auto rec = std::unique_ptr<Recordable>(static_cast<Recordable *>(recordable.release()));
-    // TODO - Handle Resource
     *instrumentation_lib->add_spans() = std::move(rec->span());
+
+    if (!has_resource)
+    {
+      *resource_span->mutable_resource() = rec->ProtoResource();
+      has_resource                       = true;
+    }
   }
 }
 

exporters/otlp/src/recordable.cc

@@ -226,6 +226,7 @@ proto::resource::v1::Resource Recordable::ProtoResource() const noexcept
       PopulateAttribute(proto.add_attributes(), kv.first, kv.second);
     }
   }
+
   return proto;
 }
 

exporters/otlp/test/recordable_test.cc

@@ -150,6 +150,28 @@ TEST(Recordable, AddLink)
   }
 }
 
+TEST(Recordable, SetResource)
+{
+  Recordable rec;
+  const std::string service_name_key = "service.name";
+  std::string service_name           = "test-otlp";
+  auto resource =
+      opentelemetry::sdk::resource::Resource::Create({{service_name_key, service_name}});
+  rec.SetResource(resource);
+
+  auto proto_resource     = rec.ProtoResource();
+  bool found_service_name = false;
+  for (size_t i = 0; i < proto_resource.attributes_size(); i++)
+  {
+    auto attr = proto_resource.attributes(static_cast<int>(i));
+    if (attr.key() == service_name_key && attr.value().string_value() == service_name)
+    {
+      found_service_name = true;
+    }
+  }
+  EXPECT_TRUE(found_service_name);
+}
+
 // Test non-int single types. Int single types are tested using templates (see IntAttributeTest)
 TEST(Recordable, SetSingleAtrribute)
 {