1 /*
2 *
3 * Copyright 2015 gRPC authors.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 */
18
19 #include <grpcpp/channel.h>
20
21 #include <chrono>
22 #include <condition_variable>
23 #include <memory>
24 #include <mutex>
25
26 #include <grpc/grpc.h>
27 #include <grpc/slice.h>
28 #include <grpc/support/alloc.h>
29 #include <grpc/support/log.h>
30 #include <grpc/support/sync.h>
31 #include <grpc/support/time.h>
32 #include <grpcpp/client_context.h>
33 #include <grpcpp/completion_queue.h>
34 #include <grpcpp/impl/call.h>
35 #include <grpcpp/impl/codegen/completion_queue_tag.h>
36 #include <grpcpp/impl/grpc_library.h>
37 #include <grpcpp/impl/rpc_method.h>
38 #include <grpcpp/security/credentials.h>
39 #include <grpcpp/support/channel_arguments.h>
40 #include <grpcpp/support/config.h>
41 #include <grpcpp/support/status.h>
42 #include <grpcpp/support/time.h>
43 #include "src/core/lib/gpr/env.h"
44 #include "src/core/lib/gpr/string.h"
45 #include "src/core/lib/gprpp/memory.h"
46 #include "src/core/lib/gprpp/thd.h"
47 #include "src/core/lib/profiling/timers.h"
48 #include "src/core/lib/surface/completion_queue.h"
49
50 namespace grpc {
51
52 static internal::GrpcLibraryInitializer g_gli_initializer;
Channel(const grpc::string & host,grpc_channel * channel)53 Channel::Channel(const grpc::string& host, grpc_channel* channel)
54 : host_(host), c_channel_(channel) {
55 g_gli_initializer.summon();
56 }
57
~Channel()58 Channel::~Channel() {
59 grpc_channel_destroy(c_channel_);
60 if (callback_cq_ != nullptr) {
61 callback_cq_->Shutdown();
62 }
63 }
64
65 namespace {
66
GetChannelInfoField(grpc_channel * channel,grpc_channel_info * channel_info,char *** channel_info_field)67 grpc::string GetChannelInfoField(grpc_channel* channel,
68 grpc_channel_info* channel_info,
69 char*** channel_info_field) {
70 char* value = nullptr;
71 memset(channel_info, 0, sizeof(*channel_info));
72 *channel_info_field = &value;
73 grpc_channel_get_info(channel, channel_info);
74 if (value == nullptr) return "";
75 grpc::string result = value;
76 gpr_free(value);
77 return result;
78 }
79
80 } // namespace
81
GetLoadBalancingPolicyName() const82 grpc::string Channel::GetLoadBalancingPolicyName() const {
83 grpc_channel_info channel_info;
84 return GetChannelInfoField(c_channel_, &channel_info,
85 &channel_info.lb_policy_name);
86 }
87
GetServiceConfigJSON() const88 grpc::string Channel::GetServiceConfigJSON() const {
89 grpc_channel_info channel_info;
90 return GetChannelInfoField(c_channel_, &channel_info,
91 &channel_info.service_config_json);
92 }
93
94 namespace experimental {
95
ChannelResetConnectionBackoff(Channel * channel)96 void ChannelResetConnectionBackoff(Channel* channel) {
97 grpc_channel_reset_connect_backoff(channel->c_channel_);
98 }
99
100 } // namespace experimental
101
CreateCall(const internal::RpcMethod & method,ClientContext * context,CompletionQueue * cq)102 internal::Call Channel::CreateCall(const internal::RpcMethod& method,
103 ClientContext* context,
104 CompletionQueue* cq) {
105 const bool kRegistered = method.channel_tag() && context->authority().empty();
106 grpc_call* c_call = nullptr;
107 if (kRegistered) {
108 c_call = grpc_channel_create_registered_call(
109 c_channel_, context->propagate_from_call_,
110 context->propagation_options_.c_bitmask(), cq->cq(),
111 method.channel_tag(), context->raw_deadline(), nullptr);
112 } else {
113 const char* host_str = nullptr;
114 if (!context->authority().empty()) {
115 host_str = context->authority_.c_str();
116 } else if (!host_.empty()) {
117 host_str = host_.c_str();
118 }
119 grpc_slice method_slice = SliceFromCopiedString(method.name());
120 grpc_slice host_slice;
121 if (host_str != nullptr) {
122 host_slice = SliceFromCopiedString(host_str);
123 }
124 c_call = grpc_channel_create_call(
125 c_channel_, context->propagate_from_call_,
126 context->propagation_options_.c_bitmask(), cq->cq(), method_slice,
127 host_str == nullptr ? nullptr : &host_slice, context->raw_deadline(),
128 nullptr);
129 grpc_slice_unref(method_slice);
130 if (host_str != nullptr) {
131 grpc_slice_unref(host_slice);
132 }
133 }
134 grpc_census_call_set_context(c_call, context->census_context());
135 context->set_call(c_call, shared_from_this());
136 return internal::Call(c_call, this, cq);
137 }
138
PerformOpsOnCall(internal::CallOpSetInterface * ops,internal::Call * call)139 void Channel::PerformOpsOnCall(internal::CallOpSetInterface* ops,
140 internal::Call* call) {
141 static const size_t MAX_OPS = 8;
142 size_t nops = 0;
143 grpc_op cops[MAX_OPS];
144 ops->FillOps(call->call(), cops, &nops);
145 GPR_ASSERT(GRPC_CALL_OK == grpc_call_start_batch(call->call(), cops, nops,
146 ops->cq_tag(), nullptr));
147 }
148
RegisterMethod(const char * method)149 void* Channel::RegisterMethod(const char* method) {
150 return grpc_channel_register_call(
151 c_channel_, method, host_.empty() ? nullptr : host_.c_str(), nullptr);
152 }
153
GetState(bool try_to_connect)154 grpc_connectivity_state Channel::GetState(bool try_to_connect) {
155 return grpc_channel_check_connectivity_state(c_channel_, try_to_connect);
156 }
157
158 namespace {
159
160 class TagSaver final : public internal::CompletionQueueTag {
161 public:
TagSaver(void * tag)162 explicit TagSaver(void* tag) : tag_(tag) {}
~TagSaver()163 ~TagSaver() override {}
FinalizeResult(void ** tag,bool * status)164 bool FinalizeResult(void** tag, bool* status) override {
165 *tag = tag_;
166 delete this;
167 return true;
168 }
169
170 private:
171 void* tag_;
172 };
173
174 } // namespace
175
NotifyOnStateChangeImpl(grpc_connectivity_state last_observed,gpr_timespec deadline,CompletionQueue * cq,void * tag)176 void Channel::NotifyOnStateChangeImpl(grpc_connectivity_state last_observed,
177 gpr_timespec deadline,
178 CompletionQueue* cq, void* tag) {
179 TagSaver* tag_saver = new TagSaver(tag);
180 grpc_channel_watch_connectivity_state(c_channel_, last_observed, deadline,
181 cq->cq(), tag_saver);
182 }
183
WaitForStateChangeImpl(grpc_connectivity_state last_observed,gpr_timespec deadline)184 bool Channel::WaitForStateChangeImpl(grpc_connectivity_state last_observed,
185 gpr_timespec deadline) {
186 CompletionQueue cq;
187 bool ok = false;
188 void* tag = nullptr;
189 NotifyOnStateChangeImpl(last_observed, deadline, &cq, nullptr);
190 cq.Next(&tag, &ok);
191 GPR_ASSERT(tag == nullptr);
192 return ok;
193 }
194
195 namespace {
196 class ShutdownCallback : public grpc_experimental_completion_queue_functor {
197 public:
ShutdownCallback()198 ShutdownCallback() { functor_run = &ShutdownCallback::Run; }
199 // TakeCQ takes ownership of the cq into the shutdown callback
200 // so that the shutdown callback will be responsible for destroying it
TakeCQ(CompletionQueue * cq)201 void TakeCQ(CompletionQueue* cq) { cq_ = cq; }
202
203 // The Run function will get invoked by the completion queue library
204 // when the shutdown is actually complete
Run(grpc_experimental_completion_queue_functor * cb,int)205 static void Run(grpc_experimental_completion_queue_functor* cb, int) {
206 auto* callback = static_cast<ShutdownCallback*>(cb);
207 delete callback->cq_;
208 grpc_core::Delete(callback);
209 }
210
211 private:
212 CompletionQueue* cq_ = nullptr;
213 };
214 } // namespace
215
CallbackCQ()216 CompletionQueue* Channel::CallbackCQ() {
217 // TODO(vjpai): Consider using a single global CQ for the default CQ
218 // if there is no explicit per-channel CQ registered
219 std::lock_guard<std::mutex> l(mu_);
220 if (callback_cq_ == nullptr) {
221 auto* shutdown_callback = grpc_core::New<ShutdownCallback>();
222 callback_cq_ = new CompletionQueue(grpc_completion_queue_attributes{
223 GRPC_CQ_CURRENT_VERSION, GRPC_CQ_CALLBACK, GRPC_CQ_DEFAULT_POLLING,
224 shutdown_callback});
225
226 // Transfer ownership of the new cq to its own shutdown callback
227 shutdown_callback->TakeCQ(callback_cq_);
228 }
229 return callback_cq_;
230 }
231
232 } // namespace grpc
233