feat(storage): add resource span attributes for ACO ( App Centric Observability ) for rewrite API in async client

Author: bajajneha27

google/cloud/storage/internal/async/connection_tracing.cc

@@ -227,8 +227,11 @@ class AsyncConnectionTracing : public storage::AsyncConnection {
   std::shared_ptr<storage::AsyncRewriterConnection> RewriteObject(
       RewriteObjectParams p) override {
     auto const enabled = internal::TracingEnabled(p.options);
+    if (!enabled) return impl_->RewriteObject(std::move(p));
+    auto span = internal::MakeSpan("storage::AsyncConnection::RewriteObject");
+    EnrichSpan(*span, p.options, p.request.destination_bucket());
     return MakeTracingAsyncRewriterConnection(
-        impl_->RewriteObject(std::move(p)), enabled);
+        impl_->RewriteObject(std::move(p)), std::move(span));
   }
 
   future<StatusOr<google::storage::v2::Bucket>> GetBucket(

google/cloud/storage/internal/async/connection_tracing_test.cc

@@ -539,6 +539,59 @@ TEST(ConnectionTracing, RewriteObject) {
                  SpanHasEvents(EventNamed("gl-cpp.storage.rewrite.iterate")))));
 }
 
+TEST(ConnectionTracing, RewriteObjectSpanEnrichment) {
+  auto span_catcher = InstallSpanCatcher();
+  PromiseWithOTelContext<StatusOr<google::storage::v2::Bucket>> p;
+
+  auto options = TracingEnabled().set<
+      google::cloud::storage_experimental::OTelSpanEnrichmentOption>(true);
+  auto mock = std::make_unique<MockAsyncConnection>();
+  EXPECT_CALL(*mock, options).WillRepeatedly(Return(options));
+
+  EXPECT_CALL(*mock, GetBucket).WillOnce(expect_context(p));
+  EXPECT_CALL(*mock, RewriteObject).WillOnce([] {
+    auto rewriter = std::make_shared<MockAsyncRewriterConnection>();
+    EXPECT_CALL(*rewriter, Iterate).WillOnce([] {
+      return make_ready_future(make_status_or(MakeRewriteResponse()));
+    });
+    return rewriter;
+  });
+
+  auto connection = MakeTracingAsyncConnection(std::move(mock));
+
+  // 1st call populates the cache
+  google::storage::v2::GetBucketRequest req;
+  req.set_name("projects/_/buckets/test-bucket");
+  auto res1 = connection->GetBucket({req, options}).then(expect_no_context);
+  google::storage::v2::Bucket bucket_meta;
+  bucket_meta.set_project("projects/123456");
+  bucket_meta.set_location("us-east1");
+  bucket_meta.set_location_type("regional");
+  p.set_value(make_status_or(std::move(bucket_meta)));
+  ASSERT_STATUS_OK(res1.get());
+
+  (void)span_catcher->GetSpans();
+
+  // 2nd call: RewriteObject uses cached bucket metadata for span enrichment
+  google::storage::v2::RewriteObjectRequest rewrite_req;
+  rewrite_req.set_destination_bucket("projects/_/buckets/test-bucket");
+  auto rewriter = connection->RewriteObject({rewrite_req, options});
+  auto r1 = rewriter->Iterate().get();
+  ASSERT_STATUS_OK(r1);
+
+  auto spans = span_catcher->GetSpans();
+  EXPECT_THAT(
+      spans,
+      ElementsAre(AllOf(
+          SpanNamed("storage::AsyncConnection::RewriteObject"),
+          SpanWithStatus(opentelemetry::trace::StatusCode::kOk),
+          SpanHasAttributes(
+              OTelAttribute<std::string>("gcp.resource.destination.id",
+                                         "projects/123456/buckets/test-bucket"),
+              OTelAttribute<std::string>("gcp.resource.destination.location",
+                                         "us-east1")))));
+}
+
 TEST(ConnectionTracing, OpenError) {
   auto span_catcher = InstallSpanCatcher();
   PromiseWithOTelContext<

google/cloud/storage/internal/async/rewriter_connection_tracing.cc

@@ -68,6 +68,13 @@ MakeTracingAsyncRewriterConnection(
     std::shared_ptr<storage::AsyncRewriterConnection> impl, bool enabled) {
   if (!enabled) return impl;
   auto span = internal::MakeSpan("storage::AsyncConnection::RewriteObject");
+  return MakeTracingAsyncRewriterConnection(std::move(impl), std::move(span));
+}
+
+std::shared_ptr<storage::AsyncRewriterConnection>
+MakeTracingAsyncRewriterConnection(
+    std::shared_ptr<storage::AsyncRewriterConnection> impl,
+    opentelemetry::nostd::shared_ptr<opentelemetry::trace::Span> span) {
   return std::make_shared<AsyncRewriterTracingConnection>(std::move(impl),
                                                           std::move(span));
 }

google/cloud/storage/internal/async/rewriter_connection_tracing.h

@@ -16,6 +16,7 @@
 #define GOOGLE_CLOUD_CPP_GOOGLE_CLOUD_STORAGE_INTERNAL_ASYNC_REWRITER_CONNECTION_TRACING_H
 
 #include "google/cloud/storage/async/rewriter_connection.h"
+#include "google/cloud/internal/opentelemetry.h"
 #include "google/cloud/options.h"
 #include "google/cloud/version.h"
 #include <memory>
@@ -29,6 +30,11 @@ std::shared_ptr<storage::AsyncRewriterConnection>
 MakeTracingAsyncRewriterConnection(
     std::shared_ptr<storage::AsyncRewriterConnection> impl, bool enabled);
 
+std::shared_ptr<storage::AsyncRewriterConnection>
+MakeTracingAsyncRewriterConnection(
+    std::shared_ptr<storage::AsyncRewriterConnection> impl,
+    opentelemetry::nostd::shared_ptr<opentelemetry::trace::Span> span);
+
 GOOGLE_CLOUD_CPP_INLINE_NAMESPACE_END
 }  // namespace storage_internal
 }  // namespace cloud