server: add method to expose authority seen by server (#29768)

markdroth · web-flow · commit 449adce98b66 · 2022-05-26T15:03:28.000-07:00
* server: add method to expose authority seen by server

* Automated change: Fix sanity tests

Co-authored-by: markdroth &lt;markdroth@users.noreply.github.com&gt;
diff --git a/include/grpcpp/impl/codegen/server_context.h b/include/grpcpp/impl/codegen/server_context.h
@@ -297,6 +297,10 @@ class ServerContextBase {
     return call_metric_recorder_;
   }
 
+  /// EXPERIMENTAL API
+  /// Returns the call's authority.
+  grpc::string_ref ExperimentalGetAuthority() const;
+
  protected:
   /// Async only. Has to be called before the rpc starts.
   /// Returns the tag in completion queue when the rpc finishes.
diff --git a/src/core/lib/surface/call.cc b/src/core/lib/surface/call.cc
@@ -104,6 +104,7 @@ class Call : public CppImplOf<Call, grpc_call> {
                                      bool is_notify_tag_closure) = 0;
   virtual bool failed_before_recv_message() const = 0;
   virtual bool is_trailers_only() const = 0;
+  virtual absl::string_view GetServerAuthority() const = 0;
   virtual void ExternalRef() = 0;
   virtual void ExternalUnref() = 0;
   virtual void InternalRef(const char* reason) = 0;
@@ -234,6 +235,13 @@ class FilterStackCall final : public Call {
     return call_failed_before_recv_message_;
   }
 
+  absl::string_view GetServerAuthority() const override {
+    const Slice* authority_metadata =
+        recv_initial_metadata_.get_pointer(HttpAuthorityMetadata());
+    if (authority_metadata == nullptr) return "";
+    return authority_metadata->as_string_view();
+  }
+
   grpc_compression_algorithm test_only_compression_algorithm() override {
     return incoming_compression_algorithm_;
   }
@@ -1942,6 +1950,10 @@ int grpc_call_failed_before_recv_message(const grpc_call* c) {
   return grpc_core::Call::FromC(c)->failed_before_recv_message();
 }
 
+absl::string_view grpc_call_server_authority(const grpc_call* call) {
+  return grpc_core::Call::FromC(call)->GetServerAuthority();
+}
+
 const char* grpc_call_error_to_string(grpc_call_error error) {
   switch (error) {
     case GRPC_CALL_ERROR:
diff --git a/src/core/lib/surface/call.h b/src/core/lib/surface/call.h
@@ -24,6 +24,7 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include "absl/strings/string_view.h"
 #include "absl/types/optional.h"
 
 #include <grpc/impl/codegen/compression_types.h>
@@ -125,6 +126,9 @@ grpc_compression_algorithm grpc_call_compression_for_level(
                     Move to surface API if requested by other languages. */
 bool grpc_call_is_trailers_only(const grpc_call* call);
 
+// Returns the authority for the call, as seen on the server side.
+absl::string_view grpc_call_server_authority(const grpc_call* call);
+
 extern grpc_core::TraceFlag grpc_call_error_trace;
 extern grpc_core::TraceFlag grpc_compression_trace;
 
diff --git a/src/core/lib/surface/server.cc b/src/core/lib/surface/server.cc
@@ -1374,7 +1374,9 @@ void Server::CallData::RecvInitialMetadataReady(void* arg,
   CallData* calld = static_cast<CallData*>(elem->call_data);
   if (error == GRPC_ERROR_NONE) {
     calld->path_ = calld->recv_initial_metadata_->Take(HttpPathMetadata());
-    calld->host_ = calld->recv_initial_metadata_->Take(HttpAuthorityMetadata());
+    auto* host =
+        calld->recv_initial_metadata_->get_pointer(HttpAuthorityMetadata());
+    if (host != nullptr) calld->host_.emplace(host->Ref());
   } else {
     (void)GRPC_ERROR_REF(error);
   }
diff --git a/src/cpp/server/server_context.cc b/src/cpp/server/server_context.cc
@@ -27,6 +27,8 @@
 #include <utility>
 #include <vector>
 
+#include "absl/strings/string_view.h"
+
 #include <grpc/compression.h>
 #include <grpc/grpc.h>
 #include <grpc/impl/codegen/compression_types.h>
@@ -52,6 +54,7 @@
 #include <grpcpp/support/interceptor.h>
 #include <grpcpp/support/server_callback.h>
 #include <grpcpp/support/server_interceptor.h>
+#include <grpcpp/support/string_ref.h>
 
 #include "src/core/lib/gprpp/ref_counted.h"
 #include "src/core/lib/gprpp/sync.h"
@@ -407,4 +410,9 @@ void ServerContextBase::CreateCallMetricRecorder() {
   call_metric_recorder_ = arena->New<experimental::CallMetricRecorder>(arena);
 }
 
+grpc::string_ref ServerContextBase::ExperimentalGetAuthority() const {
+  absl::string_view authority = grpc_call_server_authority(call_.call);
+  return grpc::string_ref(authority.data(), authority.size());
+}
+
 }  // namespace grpc
diff --git a/src/proto/grpc/testing/echo_messages.proto b/src/proto/grpc/testing/echo_messages.proto
@@ -54,6 +54,7 @@ message RequestParams {
   bool echo_metadata_initially = 17;
   bool server_notify_client_when_started = 18;
   xds.data.orca.v3.OrcaLoadReport backend_metrics = 19;
+  bool echo_host_from_authority_header = 20;
 }
 
 message EchoRequest {
diff --git a/test/cpp/end2end/end2end_test.cc b/test/cpp/end2end/end2end_test.cc
diff --git a/test/cpp/end2end/test_service_impl.cc b/test/cpp/end2end/test_service_impl.cc
diff --git a/test/cpp/end2end/test_service_impl.h b/test/cpp/end2end/test_service_impl.h

Original file line number	Diff line number	Diff line change
`@@ -54,6 +54,7 @@ message RequestParams {`
`54`	`54`	`bool echo_metadata_initially = 17;`
`55`	`55`	`bool server_notify_client_when_started = 18;`
`56`	`56`	`xds.data.orca.v3.OrcaLoadReport backend_metrics = 19;`
	`57`	`+ bool echo_host_from_authority_header = 20;`
`57`	`58`	`}`
`58`	`59`
`59`	`60`	`message EchoRequest {`