Health checking service name to be passed as a channel arg for now

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

@@ -224,8 +224,7 @@ class ChannelData {
 
   static bool ProcessResolverResultLocked(
       void* arg, const Resolver::Result& result, const char** lb_policy_name,
-      const ParsedLoadBalancingConfig** lb_policy_config,
-      const HealthCheckParsedObject** health_check);
+      const ParsedLoadBalancingConfig** lb_policy_config);
 
   grpc_error* DoPingLocked(grpc_transport_op* op);
 
@@ -932,15 +931,26 @@ class ChannelData::ClientChannelControlHelper
                              "ClientChannelControlHelper");
   }
 
-  Subchannel* CreateSubchannel(
-      const grpc_channel_args& args,
-      const HealthCheckParsedObject* health_check) override {
-    grpc_arg arg = SubchannelPoolInterface::CreateChannelArg(
+  Subchannel* CreateSubchannel(const grpc_channel_args& args) override {
+    grpc_arg args_to_add[2];
+    int num_args_to_add = 0;
+    if (chand_->service_config_ != nullptr) {
+      /*const auto* health_check_object = static_cast<HealthCheckParsedObject*>(
+          chand_->service_config_->GetParsedGlobalServiceConfigObject(
+              HealthCheckParser::ParserIndex()));
+      if (health_check_object != nullptr) {
+        args_to_add[0] = grpc_channel_arg_string_create(
+            const_cast<char*>("grpc.temp.health_check"),
+            const_cast<char*>(health_check_object->service_name()));
+        num_args_to_add++;
+      }*/
+    }
+    args_to_add[num_args_to_add++] = SubchannelPoolInterface::CreateChannelArg(
         chand_->subchannel_pool_.get());
     grpc_channel_args* new_args =
-        grpc_channel_args_copy_and_add(&args, &arg, 1);
-    Subchannel* subchannel = chand_->client_channel_factory_->CreateSubchannel(
-        new_args, health_check);
+        grpc_channel_args_copy_and_add(&args, args_to_add, num_args_to_add);
+    Subchannel* subchannel =
+        chand_->client_channel_factory_->CreateSubchannel(new_args);
     grpc_channel_args_destroy(new_args);
     return subchannel;
   }
@@ -1111,8 +1121,7 @@ ChannelData::~ChannelData() {
 // resolver result update.
 bool ChannelData::ProcessResolverResultLocked(
     void* arg, const Resolver::Result& result, const char** lb_policy_name,
-    const ParsedLoadBalancingConfig** lb_policy_config,
-    const HealthCheckParsedObject** health_check) {
+    const ParsedLoadBalancingConfig** lb_policy_config) {
   ChannelData* chand = static_cast<ChannelData*>(arg);
   ProcessedResolverResult resolver_result(result);
   const char* service_config_json = resolver_result.service_config_json();
@@ -1140,7 +1149,6 @@ bool ChannelData::ProcessResolverResultLocked(
   // Return results.
   *lb_policy_name = chand->info_lb_policy_name_.get();
   *lb_policy_config = resolver_result.lb_policy_config();
-  *health_check = resolver_result.health_check();
   return service_config_changed;
 }
 

src/core/ext/filters/client_channel/client_channel_factory.h

@@ -34,9 +34,8 @@ class ClientChannelFactory {
   virtual ~ClientChannelFactory() = default;
 
   // Creates a subchannel with the specified args.
-  virtual Subchannel* CreateSubchannel(
-      const grpc_channel_args* args,
-      const HealthCheckParsedObject* health_check) GRPC_ABSTRACT;
+  virtual Subchannel* CreateSubchannel(const grpc_channel_args* args)
+      GRPC_ABSTRACT;
 
   // Creates a channel for the specified target with the specified args.
   virtual grpc_channel* CreateChannel(

src/core/ext/filters/client_channel/health/health_check_parser.cc

@@ -61,6 +61,7 @@ UniquePtr<ServiceConfigParsedObject> HealthCheckParser::ParseGlobalParams(
       }
     }
   }
+  if (service_name == nullptr) return nullptr;
   return UniquePtr<ServiceConfigParsedObject>(
       New<HealthCheckParsedObject>(service_name));
 }

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

@@ -69,15 +69,12 @@ void LoadBalancingPolicy::ShutdownAndUnrefLocked(void* arg,
 LoadBalancingPolicy::UpdateArgs::UpdateArgs(const UpdateArgs& other) {
   addresses = other.addresses;
   config = other.config;
-  health_check = other.health_check;
   args = grpc_channel_args_copy(other.args);
 }
 
 LoadBalancingPolicy::UpdateArgs::UpdateArgs(UpdateArgs&& other) {
   addresses = std::move(other.addresses);
   config = std::move(other.config);
-  health_check = other.health_check;
-  other.health_check = nullptr;
   // TODO(roth): Use std::move() once channel args is converted to C++.
   args = other.args;
   other.args = nullptr;
@@ -87,7 +84,6 @@ LoadBalancingPolicy::UpdateArgs& LoadBalancingPolicy::UpdateArgs::operator=(
     const UpdateArgs& other) {
   addresses = other.addresses;
   config = other.config;
-  health_check = other.health_check;
   grpc_channel_args_destroy(args);
   args = grpc_channel_args_copy(other.args);
   return *this;
@@ -97,8 +93,6 @@ LoadBalancingPolicy::UpdateArgs& LoadBalancingPolicy::UpdateArgs::operator=(
     UpdateArgs&& other) {
   addresses = std::move(other.addresses);
   config = std::move(other.config);
-  health_check = other.health_check;
-  other.health_check = nullptr;
   // TODO(roth): Use std::move() once channel args is converted to C++.
   grpc_channel_args_destroy(args);
   args = other.args;

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

@@ -185,9 +185,8 @@ class LoadBalancingPolicy : public InternallyRefCounted<LoadBalancingPolicy> {
     virtual ~ChannelControlHelper() = default;
 
     /// Creates a new subchannel with the specified channel args.
-    virtual Subchannel* CreateSubchannel(
-        const grpc_channel_args& args,
-        const HealthCheckParsedObject* health_check) GRPC_ABSTRACT;
+    virtual Subchannel* CreateSubchannel(const grpc_channel_args& args)
+        GRPC_ABSTRACT;
 
     /// Creates a channel with the specified target and channel args.
     /// This can be used in cases where the LB policy needs to create a
@@ -211,7 +210,6 @@ class LoadBalancingPolicy : public InternallyRefCounted<LoadBalancingPolicy> {
   struct UpdateArgs {
     ServerAddressList addresses;
     const ParsedLoadBalancingConfig* config = nullptr;
-    const HealthCheckParsedObject* health_check = nullptr;
     const grpc_channel_args* args = nullptr;
 
     // TODO(roth): Remove everything below once channel args is

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

@@ -292,9 +292,7 @@ class GrpcLb : public LoadBalancingPolicy {
     explicit Helper(RefCountedPtr<GrpcLb> parent)
         : parent_(std::move(parent)) {}
 
-    Subchannel* CreateSubchannel(
-        const grpc_channel_args& args,
-        const HealthCheckParsedObject* health_check) override;
+    Subchannel* CreateSubchannel(const grpc_channel_args& args) override;
     grpc_channel* CreateChannel(const char* target,
                                 const grpc_channel_args& args) override;
     void UpdateState(grpc_connectivity_state state,
@@ -619,15 +617,12 @@ bool GrpcLb::Helper::CalledByCurrentChild() const {
   return child_ == parent_->child_policy_.get();
 }
 
-Subchannel* GrpcLb::Helper::CreateSubchannel(
-    const grpc_channel_args& args,
-    const HealthCheckParsedObject* health_check) {
+Subchannel* GrpcLb::Helper::CreateSubchannel(const grpc_channel_args& args) {
   if (parent_->shutting_down_ ||
       (!CalledByPendingChild() && !CalledByCurrentChild())) {
     return nullptr;
   }
-  return parent_->channel_control_helper()->CreateSubchannel(args,
-                                                             health_check);
+  return parent_->channel_control_helper()->CreateSubchannel(args);
 }
 
 grpc_channel* GrpcLb::Helper::CreateChannel(const char* target,

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

@@ -88,10 +88,9 @@ class PickFirst : public LoadBalancingPolicy {
     PickFirstSubchannelList(PickFirst* policy, TraceFlag* tracer,
                             const ServerAddressList& addresses,
                             grpc_combiner* combiner,
-                            const grpc_channel_args& args,
-                            const HealthCheckParsedObject* health_check)
+                            const grpc_channel_args& args)
         : SubchannelList(policy, tracer, addresses, combiner,
-                         policy->channel_control_helper(), args, health_check) {
+                         policy->channel_control_helper(), args) {
       // Need to maintain a ref to the LB policy as long as we maintain
       // any references to subchannels, since the subchannels'
       // pollset_sets will include the LB policy's pollset_set.
@@ -256,8 +255,7 @@ void PickFirst::UpdateLocked(UpdateArgs args) {
   grpc_channel_args* new_args =
       grpc_channel_args_copy_and_add(args.args, &new_arg, 1);
   auto subchannel_list = MakeOrphanable<PickFirstSubchannelList>(
-      this, &grpc_lb_pick_first_trace, args.addresses, combiner(), *new_args,
-      args.health_check);
+      this, &grpc_lb_pick_first_trace, args.addresses, combiner(), *new_args);
   grpc_channel_args_destroy(new_args);
   if (subchannel_list->num_subchannels() == 0) {
     // Empty update or no valid subchannels. Unsubscribe from all current

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

@@ -109,10 +109,9 @@ class RoundRobin : public LoadBalancingPolicy {
     RoundRobinSubchannelList(RoundRobin* policy, TraceFlag* tracer,
                              const ServerAddressList& addresses,
                              grpc_combiner* combiner,
-                             const grpc_channel_args& args,
-                             const HealthCheckParsedObject* health_check)
+                             const grpc_channel_args& args)
         : SubchannelList(policy, tracer, addresses, combiner,
-                         policy->channel_control_helper(), args, health_check) {
+                         policy->channel_control_helper(), args) {
       // Need to maintain a ref to the LB policy as long as we maintain
       // any references to subchannels, since the subchannels'
       // pollset_sets will include the LB policy's pollset_set.
@@ -481,8 +480,7 @@ void RoundRobin::UpdateLocked(UpdateArgs args) {
     }
   }
   latest_pending_subchannel_list_ = MakeOrphanable<RoundRobinSubchannelList>(
-      this, &grpc_lb_round_robin_trace, args.addresses, combiner(), *args.args,
-      args.health_check);
+      this, &grpc_lb_round_robin_trace, args.addresses, combiner(), *args.args);
   if (latest_pending_subchannel_list_->num_subchannels() == 0) {
     // If the new list is empty, immediately promote the new list to the
     // current list and transition to TRANSIENT_FAILURE.

src/core/ext/filters/client_channel/lb_policy/subchannel_list.h

@@ -232,8 +232,7 @@ class SubchannelList : public InternallyRefCounted<SubchannelListType> {
   SubchannelList(LoadBalancingPolicy* policy, TraceFlag* tracer,
                  const ServerAddressList& addresses, grpc_combiner* combiner,
                  LoadBalancingPolicy::ChannelControlHelper* helper,
-                 const grpc_channel_args& args,
-                 const HealthCheckParsedObject* health_check);
+                 const grpc_channel_args& args);
 
   virtual ~SubchannelList();
 
@@ -486,7 +485,7 @@ SubchannelList<SubchannelListType, SubchannelDataType>::SubchannelList(
     LoadBalancingPolicy* policy, TraceFlag* tracer,
     const ServerAddressList& addresses, grpc_combiner* combiner,
     LoadBalancingPolicy::ChannelControlHelper* helper,
-    const grpc_channel_args& args, const HealthCheckParsedObject* health_check)
+    const grpc_channel_args& args)
     : InternallyRefCounted<SubchannelListType>(tracer),
       policy_(policy),
       tracer_(tracer),
@@ -521,7 +520,7 @@ SubchannelList<SubchannelListType, SubchannelDataType>::SubchannelList(
         &args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove),
         args_to_add.data(), args_to_add.size());
     gpr_free(args_to_add[subchannel_address_arg_index].value.string);
-    Subchannel* subchannel = helper->CreateSubchannel(*new_args, health_check);
+    Subchannel* subchannel = helper->CreateSubchannel(*new_args);
     grpc_channel_args_destroy(new_args);
     if (subchannel == nullptr) {
       // Subchannel could not be created.

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

@@ -323,9 +323,7 @@ class XdsLb : public LoadBalancingPolicy {
         explicit Helper(RefCountedPtr<LocalityEntry> entry)
             : entry_(std::move(entry)) {}
 
-        Subchannel* CreateSubchannel(
-            const grpc_channel_args& args,
-            const HealthCheckParsedObject* health_check) override;
+        Subchannel* CreateSubchannel(const grpc_channel_args& args) override;
         grpc_channel* CreateChannel(const char* target,
                                     const grpc_channel_args& args) override;
         void UpdateState(grpc_connectivity_state state,
@@ -1574,14 +1572,12 @@ bool XdsLb::LocalityMap::LocalityEntry::Helper::CalledByCurrentChild() const {
 }
 
 Subchannel* XdsLb::LocalityMap::LocalityEntry::Helper::CreateSubchannel(
-    const grpc_channel_args& args,
-    const HealthCheckParsedObject* health_check) {
+    const grpc_channel_args& args) {
   if (entry_->parent_->shutting_down_ ||
       (!CalledByPendingChild() && !CalledByCurrentChild())) {
     return nullptr;
   }
-  return entry_->parent_->channel_control_helper()->CreateSubchannel(
-      args, health_check);
+  return entry_->parent_->channel_control_helper()->CreateSubchannel(args);
 }
 
 grpc_channel* XdsLb::LocalityMap::LocalityEntry::Helper::CreateChannel(

src/core/ext/filters/client_channel/resolving_lb_policy.cc

@@ -106,13 +106,10 @@ class ResolvingLoadBalancingPolicy::ResolvingControlHelper
       RefCountedPtr<ResolvingLoadBalancingPolicy> parent)
       : parent_(std::move(parent)) {}
 
-  Subchannel* CreateSubchannel(
-      const grpc_channel_args& args,
-      const HealthCheckParsedObject* health_check) override {
+  Subchannel* CreateSubchannel(const grpc_channel_args& args) override {
     if (parent_->resolver_ == nullptr) return nullptr;  // Shutting down.
     if (!CalledByCurrentChild() && !CalledByPendingChild()) return nullptr;
-    return parent_->channel_control_helper()->CreateSubchannel(args,
-                                                               health_check);
+    return parent_->channel_control_helper()->CreateSubchannel(args);
   }
 
   grpc_channel* CreateChannel(const char* target,
@@ -336,8 +333,7 @@ void ResolvingLoadBalancingPolicy::OnResolverError(grpc_error* error) {
 void ResolvingLoadBalancingPolicy::CreateOrUpdateLbPolicyLocked(
     const char* lb_policy_name,
     const ParsedLoadBalancingConfig* lb_policy_config, Resolver::Result result,
-    TraceStringVector* trace_strings,
-    const HealthCheckParsedObject* health_check) {
+    TraceStringVector* trace_strings) {
   // If the child policy name changes, we need to create a new child
   // policy.  When this happens, we leave child_policy_ as-is and store
   // the new child policy in pending_child_policy_.  Once the new child
@@ -430,7 +426,6 @@ void ResolvingLoadBalancingPolicy::CreateOrUpdateLbPolicyLocked(
   UpdateArgs update_args;
   update_args.addresses = std::move(result.addresses);
   update_args.config = std::move(lb_policy_config);
-  update_args.health_check = health_check;
   // TODO(roth): Once channel args is converted to C++, use std::move() here.
   update_args.args = result.args;
   result.args = nullptr;
@@ -535,12 +530,11 @@ void ResolvingLoadBalancingPolicy::OnResolverResultChangedLocked(
   // Process the resolver result.
   const char* lb_policy_name = nullptr;
   const ParsedLoadBalancingConfig* lb_policy_config = nullptr;
-  const HealthCheckParsedObject* health_check = nullptr;
   bool service_config_changed = false;
   if (process_resolver_result_ != nullptr) {
-    service_config_changed = process_resolver_result_(
-        process_resolver_result_user_data_, result, &lb_policy_name,
-        &lb_policy_config, &health_check);
+    service_config_changed =
+        process_resolver_result_(process_resolver_result_user_data_, result,
+                                 &lb_policy_name, &lb_policy_config);
   } else {
     lb_policy_name = child_policy_name_.get();
     lb_policy_config = child_lb_config_;
@@ -548,7 +542,7 @@ void ResolvingLoadBalancingPolicy::OnResolverResultChangedLocked(
   GPR_ASSERT(lb_policy_name != nullptr);
   // Create or update LB policy, as needed.
   CreateOrUpdateLbPolicyLocked(lb_policy_name, lb_policy_config,
-                               std::move(result), &trace_strings, health_check);
+                               std::move(result), &trace_strings);
   // Add channel trace event.
   if (channelz_node() != nullptr) {
     if (service_config_changed) {

src/core/ext/filters/client_channel/resolving_lb_policy.h

@@ -68,8 +68,7 @@ class ResolvingLoadBalancingPolicy : public LoadBalancingPolicy {
   typedef bool (*ProcessResolverResultCallback)(
       void* user_data, const Resolver::Result& result,
       const char** lb_policy_name,
-      const ParsedLoadBalancingConfig** lb_policy_config,
-      const HealthCheckParsedObject** health_check);
+      const ParsedLoadBalancingConfig** lb_policy_config);
   // If error is set when this returns, then construction failed, and
   // the caller may not use the new object.
   ResolvingLoadBalancingPolicy(
@@ -108,8 +107,7 @@ class ResolvingLoadBalancingPolicy : public LoadBalancingPolicy {
   void CreateOrUpdateLbPolicyLocked(
       const char* lb_policy_name,
       const ParsedLoadBalancingConfig* lb_policy_config,
-      Resolver::Result result, TraceStringVector* trace_strings,
-      const HealthCheckParsedObject* health_check);
+      Resolver::Result result, TraceStringVector* trace_strings);
   OrphanablePtr<LoadBalancingPolicy> CreateLbPolicyLocked(
       const char* lb_policy_name, const grpc_channel_args& args,
       TraceStringVector* trace_strings);

src/core/ext/filters/client_channel/subchannel.cc

@@ -532,8 +532,7 @@ BackOff::Options ParseArgsForBackoffValues(
 }  // namespace
 
 Subchannel::Subchannel(SubchannelKey* key, grpc_connector* connector,
-                       const grpc_channel_args* args,
-                       const HealthCheckParsedObject* health_check)
+                       const grpc_channel_args* args)
     : key_(key),
       connector_(connector),
       backoff_(ParseArgsForBackoffValues(args, &min_connect_timeout_ms_)) {
@@ -565,10 +564,9 @@ Subchannel::Subchannel(SubchannelKey* key, grpc_connector* connector,
                                "subchannel");
   grpc_connectivity_state_init(&state_and_health_tracker_, GRPC_CHANNEL_IDLE,
                                "subchannel");
-  if (health_check != nullptr) {
   health_check_service_name_ =
-        UniquePtr<char>(gpr_strdup(health_check->service_name()));
-  }
+      UniquePtr<char>(gpr_strdup(grpc_channel_arg_get_string(
+          grpc_channel_args_find(args_, "grpc.temp.health_check"))));
   const grpc_arg* arg = grpc_channel_args_find(args_, GRPC_ARG_ENABLE_CHANNELZ);
   const bool channelz_enabled =
       grpc_channel_arg_get_bool(arg, GRPC_ENABLE_CHANNELZ_DEFAULT);
@@ -603,8 +601,7 @@ Subchannel::~Subchannel() {
 }
 
 Subchannel* Subchannel::Create(grpc_connector* connector,
-                               const grpc_channel_args* args,
-                               const HealthCheckParsedObject* health_check) {
+                               const grpc_channel_args* args) {
   SubchannelKey* key = New<SubchannelKey>(args);
   SubchannelPoolInterface* subchannel_pool =
       SubchannelPoolInterface::GetSubchannelPoolFromChannelArgs(args);
@@ -614,7 +611,7 @@ Subchannel* Subchannel::Create(grpc_connector* connector,
     Delete(key);
     return c;
   }
-  c = New<Subchannel>(key, connector, args, health_check);
+  c = New<Subchannel>(key, connector, args);
   // Try to register the subchannel before setting the subchannel pool.
   // Otherwise, in case of a registration race, unreffing c in
   // RegisterSubchannel() will cause c to be tried to be unregistered, while

src/core/ext/filters/client_channel/subchannel.h

@@ -179,14 +179,12 @@ class Subchannel {
  public:
   // The ctor and dtor are not intended to use directly.
   Subchannel(SubchannelKey* key, grpc_connector* connector,
-             const grpc_channel_args* args,
-             const HealthCheckParsedObject* health_check);
+             const grpc_channel_args* args);
   ~Subchannel();
 
   // Creates a subchannel given \a connector and \a args.
   static Subchannel* Create(grpc_connector* connector,
-                            const grpc_channel_args* args,
-                            const HealthCheckParsedObject* health_check);
+                            const grpc_channel_args* args);
 
   // Strong and weak refcounting.
   Subchannel* Ref(GRPC_SUBCHANNEL_REF_EXTRA_ARGS);

src/core/ext/transport/chttp2/client/insecure/channel_create.cc

@@ -37,13 +37,11 @@ namespace grpc_core {
 
 class Chttp2InsecureClientChannelFactory : public ClientChannelFactory {
  public:
-  Subchannel* CreateSubchannel(
-      const grpc_channel_args* args,
-      const HealthCheckParsedObject* health_check) override {
+  Subchannel* CreateSubchannel(const grpc_channel_args* args) override {
     grpc_channel_args* new_args =
         grpc_default_authority_add_if_not_present(args);
     grpc_connector* connector = grpc_chttp2_connector_create();
-    Subchannel* s = Subchannel::Create(connector, new_args, health_check);
+    Subchannel* s = Subchannel::Create(connector, new_args);
     grpc_connector_unref(connector);
     grpc_channel_args_destroy(new_args);
     return s;

src/core/ext/transport/chttp2/client/secure/secure_channel_create.cc

@@ -44,9 +44,7 @@ namespace grpc_core {
 
 class Chttp2SecureClientChannelFactory : public ClientChannelFactory {
  public:
-  Subchannel* CreateSubchannel(
-      const grpc_channel_args* args,
-      const HealthCheckParsedObject* health_check) override {
+  Subchannel* CreateSubchannel(const grpc_channel_args* args) override {
     grpc_channel_args* new_args = GetSecureNamingChannelArgs(args);
     if (new_args == nullptr) {
       gpr_log(GPR_ERROR,
@@ -54,7 +52,7 @@ class Chttp2SecureClientChannelFactory : public ClientChannelFactory {
       return nullptr;
     }
     grpc_connector* connector = grpc_chttp2_connector_create();
-    Subchannel* s = Subchannel::Create(connector, new_args, health_check);
+    Subchannel* s = Subchannel::Create(connector, new_args);
     grpc_connector_unref(connector);
     grpc_channel_args_destroy(new_args);
     return s;

test/core/util/test_lb_policies.cc

@@ -141,11 +141,8 @@ class InterceptRecvTrailingMetadataLoadBalancingPolicy
         InterceptRecvTrailingMetadataCallback cb, void* user_data)
         : parent_(std::move(parent)), cb_(cb), user_data_(user_data) {}
 
-    Subchannel* CreateSubchannel(
-        const grpc_channel_args& args,
-        const HealthCheckParsedObject* health_check) override {
-      return parent_->channel_control_helper()->CreateSubchannel(args,
-                                                                 health_check);
+    Subchannel* CreateSubchannel(const grpc_channel_args& args) override {
+      return parent_->channel_control_helper()->CreateSubchannel(args);
     }
 
     grpc_channel* CreateChannel(const char* target,

test/cpp/microbenchmarks/bm_call_create.cc

@@ -322,8 +322,7 @@ static void DoNothing(void* arg, grpc_error* error) {}
 class FakeClientChannelFactory : public grpc_core::ClientChannelFactory {
  public:
   grpc_core::Subchannel* CreateSubchannel(
-      const grpc_channel_args* args,
-      const grpc_core::HealthCheckParsedObject* health_check) override {
+      const grpc_channel_args* args) override {
     return nullptr;
   }
   grpc_channel* CreateChannel(const char* target,