[LB policies] use helper GetAuthority() instead of GRPC_ARG_SERVER_URI channel arg (#33671)

src/core/BUILD

@@ -3917,7 +3917,6 @@ grpc_cc_library(
         "//:ref_counted_ptr",
         "//:server_address",
         "//:sockaddr_utils",
-        "//:uri_parser",
         "//:work_serializer",
     ],
 )
@@ -4004,7 +4003,6 @@ grpc_cc_library(
         "//:ref_counted_ptr",
         "//:rls_upb",
         "//:server_address",
-        "//:uri_parser",
         "//:work_serializer",
     ],
 )

src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc

@@ -78,7 +78,6 @@
 #include "absl/strings/str_format.h"
 #include "absl/strings/str_join.h"
 #include "absl/strings/string_view.h"
-#include "absl/strings/strip.h"
 #include "absl/types/optional.h"
 #include "absl/types/variant.h"
 #include "upb/upb.hpp"
@@ -144,7 +143,6 @@
 #include "src/core/lib/surface/channel_stack_type.h"
 #include "src/core/lib/transport/connectivity_state.h"
 #include "src/core/lib/transport/metadata_batch.h"
-#include "src/core/lib/uri/uri_parser.h"
 
 #define GRPC_GRPCLB_INITIAL_CONNECT_BACKOFF_SECONDS 1
 #define GRPC_GRPCLB_RECONNECT_BACKOFF_MULTIPLIER 1.6
@@ -523,8 +521,6 @@ class GrpcLb : public LoadBalancingPolicy {
   void StartSubchannelCacheTimerLocked();
   void OnSubchannelCacheTimerLocked();
 
-  // Who the client is trying to communicate with.
-  std::string server_name_;
   // Configurations for the policy.
   RefCountedPtr<GrpcLbConfig> config_;
 
@@ -854,8 +850,6 @@ GrpcLb::BalancerCallState::BalancerCallState(
   // Init the LB call. Note that the LB call will progress every time there's
   // activity in grpclb_policy_->interested_parties(), which is comprised of
   // the polling entities from client_channel.
-  GPR_ASSERT(!grpclb_policy()->server_name_.empty());
-  // Closure Initialization
   GRPC_CLOSURE_INIT(&lb_on_initial_request_sent_, OnInitialRequestSent, this,
                     grpc_schedule_on_exec_ctx);
   GRPC_CLOSURE_INIT(&lb_on_balancer_message_received_,
@@ -877,8 +871,8 @@ GrpcLb::BalancerCallState::BalancerCallState(
   upb::Arena arena;
   grpc_slice request_payload_slice = GrpcLbRequestCreate(
       grpclb_policy()->config_->service_name().empty()
-          ? grpclb_policy()->server_name_.c_str()
-          : grpclb_policy()->config_->service_name().c_str(),
+          ? grpclb_policy()->channel_control_helper()->GetAuthority()
+          : grpclb_policy()->config_->service_name(),
       arena.ptr());
   send_message_payload_ =
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
@@ -1372,10 +1366,6 @@ ChannelArgs BuildBalancerChannelArgs(
             // Strip out the service config, since we don't want the LB policy
             // config specified for the parent channel to affect the LB channel.
             .Remove(GRPC_ARG_SERVICE_CONFIG)
-            // The channel arg for the server URI, since that will be different
-            // for the LB channel than for the parent channel.  The client
-            // channel factory will re-add this arg with the right value.
-            .Remove(GRPC_ARG_SERVER_URI)
             // The fake resolver response generator, because we are replacing it
             // with the one from the grpclb policy, used to propagate updates to
             // the LB channel.
@@ -1411,16 +1401,8 @@ ChannelArgs BuildBalancerChannelArgs(
 // ctor and dtor
 //
 
-std::string GetServerNameFromChannelArgs(const ChannelArgs& args) {
-  absl::StatusOr<URI> uri =
-      URI::Parse(args.GetString(GRPC_ARG_SERVER_URI).value());
-  GPR_ASSERT(uri.ok() && !uri->path().empty());
-  return std::string(absl::StripPrefix(uri->path(), "/"));
-}
-
 GrpcLb::GrpcLb(Args args)
     : LoadBalancingPolicy(std::move(args)),
-      server_name_(GetServerNameFromChannelArgs(channel_args())),
       response_generator_(MakeRefCounted<FakeResolverResponseGenerator>()),
       lb_call_timeout_(std::max(
           Duration::Zero(),
@@ -1451,7 +1433,8 @@ GrpcLb::GrpcLb(Args args)
   if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_glb_trace)) {
     gpr_log(GPR_INFO,
             "[grpclb %p] Will use '%s' as the server name for LB request.",
-            this, server_name_.c_str());
+            this,
+            std::string(channel_control_helper()->GetAuthority()).c_str());
   }
 }
 
@@ -1581,7 +1564,8 @@ absl::Status GrpcLb::UpdateBalancerChannelLocked() {
       BuildBalancerChannelArgs(response_generator_.get(), args_);
   // Create balancer channel if needed.
   if (lb_channel_ == nullptr) {
-    std::string uri_str = absl::StrCat("fake:///", server_name_);
+    std::string uri_str =
+        absl::StrCat("fake:///", channel_control_helper()->GetAuthority());
     lb_channel_ =
         grpc_channel_create(uri_str.c_str(), channel_credentials.get(),
                             lb_channel_args.ToC().get());

src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.cc

@@ -59,15 +59,16 @@ grpc_slice grpc_grpclb_request_encode(
 
 }  // namespace
 
-grpc_slice GrpcLbRequestCreate(const char* lb_service_name, upb_Arena* arena) {
+grpc_slice GrpcLbRequestCreate(absl::string_view lb_service_name,
+                               upb_Arena* arena) {
   grpc_lb_v1_LoadBalanceRequest* req = grpc_lb_v1_LoadBalanceRequest_new(arena);
   grpc_lb_v1_InitialLoadBalanceRequest* initial_request =
       grpc_lb_v1_LoadBalanceRequest_mutable_initial_request(req, arena);
-  size_t name_len = std::min(strlen(lb_service_name),
+  size_t name_len = std::min(lb_service_name.size(),
                              size_t{GRPC_GRPCLB_SERVICE_NAME_MAX_LENGTH});
   grpc_lb_v1_InitialLoadBalanceRequest_set_name(
       initial_request,
-      upb_StringView_FromDataAndSize(lb_service_name, name_len));
+      upb_StringView_FromDataAndSize(lb_service_name.data(), name_len));
   return grpc_grpclb_request_encode(req, arena);
 }
 

src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.h

@@ -24,6 +24,7 @@
 
 #include <vector>
 
+#include "absl/strings/string_view.h"
 #include "upb/mem/arena.h"
 
 #include <grpc/slice.h>
@@ -56,7 +57,8 @@ struct GrpcLbResponse {
 };
 
 // Creates a serialized grpclb request.
-grpc_slice GrpcLbRequestCreate(const char* lb_service_name, upb_Arena* arena);
+grpc_slice GrpcLbRequestCreate(absl::string_view lb_service_name,
+                               upb_Arena* arena);
 
 // Creates a serialized grpclb load report request.
 grpc_slice GrpcLbLoadReportRequestCreate(

src/core/ext/filters/client_channel/lb_policy/rls/rls.cc

@@ -48,7 +48,6 @@
 #include "absl/strings/str_format.h"
 #include "absl/strings/str_join.h"
 #include "absl/strings/string_view.h"
-#include "absl/strings/strip.h"
 #include "absl/types/optional.h"
 #include "upb/base/string_view.h"
 #include "upb/upb.hpp"
@@ -103,7 +102,6 @@
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/transport/connectivity_state.h"
 #include "src/core/lib/transport/error_utils.h"
-#include "src/core/lib/uri/uri_parser.h"
 #include "src/proto/grpc/lookup/v1/rls.upb.h"
 
 namespace grpc_core {
@@ -693,9 +691,6 @@ class RlsLb : public LoadBalancingPolicy {
   // Updates the picker in the work serializer.
   void UpdatePickerLocked() ABSL_LOCKS_EXCLUDED(&mu_);
 
-  // The name of the server for the channel.
-  std::string server_name_;
-
   // Mutex to guard LB policy state that is accessed by the picker.
   Mutex mu_;
   bool is_shutdown_ ABSL_GUARDED_BY(mu_) = false;
@@ -899,7 +894,7 @@ void RlsLb::ChildPolicyWrapper::ChildPolicyHelper::UpdateState(
 // Builds the key to be used for a request based on path and initial_metadata.
 std::map<std::string, std::string> BuildKeyMap(
     const RlsLbConfig::KeyBuilderMap& key_builder_map, absl::string_view path,
-    const std::string& host,
+    absl::string_view host,
     const LoadBalancingPolicy::MetadataInterface* initial_metadata) {
   size_t last_slash_pos = path.npos;  // May need this a few times, so cache it.
   // Find key builder for this path.
@@ -935,7 +930,7 @@ std::map<std::string, std::string> BuildKeyMap(
                  key_builder->constant_keys.end());
   // Add host key.
   if (!key_builder->host_key.empty()) {
-    key_map[key_builder->host_key] = host;
+    key_map[key_builder->host_key] = std::string(host);
   }
   // Add service key.
   if (!key_builder->service_key.empty()) {
@@ -970,9 +965,10 @@ RlsLb::Picker::Picker(RefCountedPtr<RlsLb> lb_policy)
 
 LoadBalancingPolicy::PickResult RlsLb::Picker::Pick(PickArgs args) {
   // Construct key for request.
-  RequestKey key = {BuildKeyMap(config_->key_builder_map(), args.path,
-                                lb_policy_->server_name_,
-                                args.initial_metadata)};
+  RequestKey key = {
+      BuildKeyMap(config_->key_builder_map(), args.path,
+                  lb_policy_->channel_control_helper()->GetAuthority(),
+                  args.initial_metadata)};
   if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_rls_trace)) {
     gpr_log(GPR_INFO, "[rlslb %p] picker=%p: request keys: %s",
             lb_policy_.get(), this, key.ToString().c_str());
@@ -1857,18 +1853,7 @@ RlsLb::ResponseInfo RlsLb::RlsRequest::ParseResponseProto() {
 // RlsLb
 //
 
-std::string GetServerUri(const ChannelArgs& args) {
-  auto server_uri_str = args.GetString(GRPC_ARG_SERVER_URI);
-  GPR_ASSERT(server_uri_str.has_value());
-  absl::StatusOr<URI> uri = URI::Parse(*server_uri_str);
-  GPR_ASSERT(uri.ok());
-  return std::string(absl::StripPrefix(uri->path(), "/"));
-}
-
-RlsLb::RlsLb(Args args)
-    : LoadBalancingPolicy(std::move(args)),
-      server_name_(GetServerUri(channel_args())),
-      cache_(this) {
+RlsLb::RlsLb(Args args) : LoadBalancingPolicy(std::move(args)), cache_(this) {
   if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_rls_trace)) {
     gpr_log(GPR_INFO, "[rlslb %p] policy created", this);
   }