Set default service.name if missing (#616)

Author: lalitb

CHANGELOG.md

@@ -18,6 +18,7 @@ Increment the:
 * [EXPORTER] Added Zipkin Exporter. ([#471](https://github.com/open-telemetry/opentelemetry-cpp/pull/471))
 * [API] Added Jaeger propagator. ([#599](https://github.com/open-telemetry/opentelemetry-cpp/pull/599))
 * [PROPAGATOR] Added Composite Propagator ([#597](https://github.com/open-telemetry/opentelemetry-cpp/pull/597))
+* [SDK] Add service.name if missing in Resource ([#616](https://github.com/open-telemetry/opentelemetry-cpp/pull/616))
 
 ## [0.2.0] 2021-03-02
 

sdk/src/resource/resource.cc

@@ -9,9 +9,11 @@ namespace sdk
 namespace resource
 {
 
-const std::string kTelemetrySdkLanguage = "telemetry.sdk.language";
-const std::string kTelemetrySdkName     = "telemetry.sdk.name";
-const std::string kTelemetrySdkVersion  = "telemetry.sdk.version";
+const std::string kTelemetrySdkLanguage  = "telemetry.sdk.language";
+const std::string kTelemetrySdkName      = "telemetry.sdk.name";
+const std::string kTelemetrySdkVersion   = "telemetry.sdk.version";
+const std::string kServiceName           = "service.name";
+const std::string kProcessExecutableName = "process.executable.name";
 
 Resource::Resource(const ResourceAttributes &attributes) noexcept : attributes_(attributes) {}
 
@@ -25,15 +27,19 @@ Resource Resource::Merge(const Resource &other) noexcept
 Resource Resource::Create(const ResourceAttributes &attributes)
 {
   static auto otel_resource = OTELResourceDetector().Detect();
-  auto default_resource     = Resource::GetDefault();
+  auto resource = Resource::GetDefault().Merge(otel_resource).Merge(Resource(attributes));
 
-  if (attributes.size() > 0)
+  if (resource.attributes_.find(kServiceName) == resource.attributes_.end())
   {
-    Resource tmp_resource(attributes);
-    auto merged_resource = tmp_resource.Merge(default_resource);
-    return merged_resource.Merge(otel_resource);
+    std::string default_service_name = "unknown_service";
+    auto it_process_executable_name  = resource.attributes_.find(kProcessExecutableName);
+    if (it_process_executable_name != resource.attributes_.end())
+    {
+      default_service_name += ":" + nostd::get<std::string>(it_process_executable_name->second);
+    }
+    resource.attributes_[kServiceName] = default_service_name;
   }
-  return default_resource.Merge(otel_resource);
+  return resource;
 }
 
 Resource &Resource::GetEmpty()

sdk/test/resource/resource_test.cc

@@ -19,7 +19,7 @@ class TestResource : public opentelemetry::sdk::resource::Resource
   {}
 };
 
-TEST(ResourceTest, create)
+TEST(ResourceTest, create_without_servicename)
 {
 
   opentelemetry::sdk::resource::ResourceAttributes expected_attributes = {
@@ -28,15 +28,46 @@ TEST(ResourceTest, create)
       {"cost", 234.23},
       {"telemetry.sdk.language", "cpp"},
       {"telemetry.sdk.name", "opentelemetry"},
-      {"telemetry.sdk.version", OPENTELEMETRY_SDK_VERSION}};
+      {"telemetry.sdk.version", OPENTELEMETRY_SDK_VERSION},
+      {"service.name", "unknown_service"}};
 
   opentelemetry::sdk::resource::ResourceAttributes attributes = {
       {"service", "backend"}, {"version", (uint32_t)1}, {"cost", 234.23}};
-  auto resource2            = opentelemetry::sdk::resource::Resource::Create(attributes);
-  auto received_attributes2 = resource2.GetAttributes();
-  for (auto &e : received_attributes2)
+  auto resource            = opentelemetry::sdk::resource::Resource::Create(attributes);
+  auto received_attributes = resource.GetAttributes();
+  for (auto &e : received_attributes)
   {
+    EXPECT_TRUE(expected_attributes.find(e.first) != expected_attributes.end());
+    if (expected_attributes.find(e.first) != expected_attributes.end())
+      if (e.first == "version")
+        EXPECT_EQ(opentelemetry::nostd::get<uint32_t>(expected_attributes.find(e.first)->second),
+                  opentelemetry::nostd::get<uint32_t>(e.second));
+      else if (e.first == "cost")
+        EXPECT_EQ(opentelemetry::nostd::get<double>(expected_attributes.find(e.first)->second),
+                  opentelemetry::nostd::get<double>(e.second));
+      else
+        EXPECT_EQ(opentelemetry::nostd::get<std::string>(expected_attributes.find(e.first)->second),
+                  opentelemetry::nostd::get<std::string>(e.second));
+  }
+  EXPECT_EQ(received_attributes.size(), expected_attributes.size());  // for missing service.name
+}
 
+TEST(ResourceTest, create_with_servicename)
+{
+  opentelemetry::sdk::resource::ResourceAttributes expected_attributes = {
+      {"version", (uint32_t)1},
+      {"cost", 234.23},
+      {"telemetry.sdk.language", "cpp"},
+      {"telemetry.sdk.name", "opentelemetry"},
+      {"telemetry.sdk.version", OPENTELEMETRY_SDK_VERSION},
+      {"service.name", "backend"},
+  };
+  opentelemetry::sdk::resource::ResourceAttributes attributes = {
+      {"service.name", "backend"}, {"version", (uint32_t)1}, {"cost", 234.23}};
+  auto resource            = opentelemetry::sdk::resource::Resource::Create(attributes);
+  auto received_attributes = resource.GetAttributes();
+  for (auto &e : received_attributes)
+  {
     EXPECT_TRUE(expected_attributes.find(e.first) != expected_attributes.end());
     if (expected_attributes.find(e.first) != expected_attributes.end())
       if (e.first == "version")
@@ -49,9 +80,29 @@ TEST(ResourceTest, create)
         EXPECT_EQ(opentelemetry::nostd::get<std::string>(expected_attributes.find(e.first)->second),
                   opentelemetry::nostd::get<std::string>(e.second));
   }
-  EXPECT_EQ(received_attributes2.size(), expected_attributes.size());
+  EXPECT_EQ(received_attributes.size(), expected_attributes.size());  // for missing service.name
 }
 
+TEST(ResourceTest, create_with_emptyatrributes)
+{
+  opentelemetry::sdk::resource::ResourceAttributes expected_attributes = {
+      {"telemetry.sdk.language", "cpp"},
+      {"telemetry.sdk.name", "opentelemetry"},
+      {"telemetry.sdk.version", OPENTELEMETRY_SDK_VERSION},
+      {"service.name", "unknown_service"},
+  };
+  opentelemetry::sdk::resource::ResourceAttributes attributes = {};
+  auto resource            = opentelemetry::sdk::resource::Resource::Create(attributes);
+  auto received_attributes = resource.GetAttributes();
+  for (auto &e : received_attributes)
+  {
+    EXPECT_TRUE(expected_attributes.find(e.first) != expected_attributes.end());
+    if (expected_attributes.find(e.first) != expected_attributes.end())
+      EXPECT_EQ(opentelemetry::nostd::get<std::string>(expected_attributes.find(e.first)->second),
+                opentelemetry::nostd::get<std::string>(e.second));
+  }
+  EXPECT_EQ(received_attributes.size(), expected_attributes.size());  // for missing service.name
+}
 TEST(ResourceTest, Merge)
 {
   TestResource resource1(
@@ -72,6 +123,7 @@ TEST(ResourceTest, Merge)
   }
   EXPECT_EQ(received_attributes.size(), expected_attributes.size());
 }
+
 TEST(ResourceTest, MergeEmptyString)
 {
   TestResource resource1({{"service", "backend"}, {"host", "service-host"}});