legacy-libs/grpc-cloned/deps/grpc/src/core/ext/filters/client_channel/channel_connectivity.cc

   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 <grpc/support/port_platform.h>
  20
  21 #include "src/core/lib/surface/channel.h"
  22
  23 #include <inttypes.h>
  24
  25 #include <grpc/support/alloc.h>
  26 #include <grpc/support/log.h>
  27
  28 #include "src/core/ext/filters/client_channel/client_channel.h"
  29 #include "src/core/lib/iomgr/timer.h"
  30 #include "src/core/lib/surface/api_trace.h"
  31 #include "src/core/lib/surface/completion_queue.h"
  32
  33 grpc_connectivity_state grpc_channel_check_connectivity_state(
  34     grpc_channel* channel, int try_to_connect) {
  35   /* forward through to the underlying client channel */
  36   grpc_channel_element* client_channel_elem =
  37       grpc_channel_stack_last_element(grpc_channel_get_channel_stack(channel));
  38   grpc_core::ApplicationCallbackExecCtx callback_exec_ctx;
  39   grpc_core::ExecCtx exec_ctx;
  40   grpc_connectivity_state state;
  41   GRPC_API_TRACE(
  42       "grpc_channel_check_connectivity_state(channel=%p, try_to_connect=%d)", 2,
  43       (channel, try_to_connect));
  44   if (GPR_LIKELY(client_channel_elem->filter == &grpc_client_channel_filter)) {
  45     state = grpc_client_channel_check_connectivity_state(client_channel_elem,
  46                                                          try_to_connect);
  47
  48     return state;
  49   }
  50   gpr_log(GPR_ERROR,
  51           "grpc_channel_check_connectivity_state called on something that is "
  52           "not a client channel, but '%s'",
  53           client_channel_elem->filter->name);
  54
  55   return GRPC_CHANNEL_SHUTDOWN;
  56 }
  57
  58 typedef enum {
  59   WAITING,
  60   READY_TO_CALL_BACK,
  61   CALLING_BACK_AND_FINISHED,
  62 } callback_phase;
  63
  64 namespace {
  65 struct state_watcher {
  66   gpr_mu mu;
  67   callback_phase phase;
  68   grpc_closure on_complete;
  69   grpc_closure on_timeout;
  70   grpc_closure watcher_timer_init;
  71   grpc_timer alarm;
  72   grpc_connectivity_state state;
  73   grpc_completion_queue* cq;
  74   grpc_cq_completion completion_storage;
  75   grpc_channel* channel;
  76   grpc_error* error;
  77   void* tag;
  78 };
  79 }  // namespace
  80
  81 static void delete_state_watcher(state_watcher* w) {
  82   grpc_channel_element* client_channel_elem = grpc_channel_stack_last_element(
  83       grpc_channel_get_channel_stack(w->channel));
  84   if (client_channel_elem->filter == &grpc_client_channel_filter) {
  85     GRPC_CHANNEL_INTERNAL_UNREF(w->channel, "watch_channel_connectivity");
  86   } else {
  87     abort();
  88   }
  89   gpr_mu_destroy(&w->mu);
  90   gpr_free(w);
  91 }
  92
  93 static void finished_completion(void* pw, grpc_cq_completion* ignored) {
  94   bool should_delete = false;
  95   state_watcher* w = static_cast<state_watcher*>(pw);
  96   gpr_mu_lock(&w->mu);
  97   switch (w->phase) {
  98     case WAITING:
  99     case READY_TO_CALL_BACK:
 100       GPR_UNREACHABLE_CODE(return );
 101     case CALLING_BACK_AND_FINISHED:
 102       should_delete = true;
 103       break;
 104   }
 105   gpr_mu_unlock(&w->mu);
 106
 107   if (should_delete) {
 108     delete_state_watcher(w);
 109   }
 110 }
 111
 112 static void partly_done(state_watcher* w, bool due_to_completion,
 113                         grpc_error* error) {
 114   bool end_op = false;
 115   void* end_op_tag = nullptr;
 116   grpc_error* end_op_error = nullptr;
 117   grpc_completion_queue* end_op_cq = nullptr;
 118   grpc_cq_completion* end_op_completion_storage = nullptr;
 119
 120   if (due_to_completion) {
 121     grpc_timer_cancel(&w->alarm);
 122   } else {
 123     grpc_channel_element* client_channel_elem = grpc_channel_stack_last_element(
 124         grpc_channel_get_channel_stack(w->channel));
 125     grpc_client_channel_watch_connectivity_state(
 126         client_channel_elem,
 127         grpc_polling_entity_create_from_pollset(grpc_cq_pollset(w->cq)),
 128         nullptr, &w->on_complete, nullptr);
 129   }
 130
 131   gpr_mu_lock(&w->mu);
 132
 133   if (due_to_completion) {
 134     if (GRPC_TRACE_FLAG_ENABLED(grpc_trace_operation_failures)) {
 135       GRPC_LOG_IF_ERROR("watch_completion_error", GRPC_ERROR_REF(error));
 136     }
 137     GRPC_ERROR_UNREF(error);
 138     error = GRPC_ERROR_NONE;
 139   } else {
 140     if (error == GRPC_ERROR_NONE) {
 141       error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
 142           "Timed out waiting for connection state change");
 143     } else if (error == GRPC_ERROR_CANCELLED) {
 144       error = GRPC_ERROR_NONE;
 145     }
 146   }
 147   switch (w->phase) {
 148     case WAITING:
 149       GRPC_ERROR_REF(error);
 150       w->error = error;
 151       w->phase = READY_TO_CALL_BACK;
 152       break;
 153     case READY_TO_CALL_BACK:
 154       if (error != GRPC_ERROR_NONE) {
 155         GPR_ASSERT(!due_to_completion);
 156         GRPC_ERROR_UNREF(w->error);
 157         GRPC_ERROR_REF(error);
 158         w->error = error;
 159       }
 160       w->phase = CALLING_BACK_AND_FINISHED;
 161       end_op = true;
 162       end_op_cq = w->cq;
 163       end_op_tag = w->tag;
 164       end_op_error = w->error;
 165       end_op_completion_storage = &w->completion_storage;
 166       break;
 167     case CALLING_BACK_AND_FINISHED:
 168       GPR_UNREACHABLE_CODE(return );
 169       break;
 170   }
 171   gpr_mu_unlock(&w->mu);
 172
 173   if (end_op) {
 174     grpc_cq_end_op(end_op_cq, end_op_tag, end_op_error, finished_completion, w,
 175                    end_op_completion_storage);
 176   }
 177
 178   GRPC_ERROR_UNREF(error);
 179 }
 180
 181 static void watch_complete(void* pw, grpc_error* error) {
 182   partly_done(static_cast<state_watcher*>(pw), true, GRPC_ERROR_REF(error));
 183 }
 184
 185 static void timeout_complete(void* pw, grpc_error* error) {
 186   partly_done(static_cast<state_watcher*>(pw), false, GRPC_ERROR_REF(error));
 187 }
 188
 189 int grpc_channel_num_external_connectivity_watchers(grpc_channel* channel) {
 190   grpc_channel_element* client_channel_elem =
 191       grpc_channel_stack_last_element(grpc_channel_get_channel_stack(channel));
 192   return grpc_client_channel_num_external_connectivity_watchers(
 193       client_channel_elem);
 194 }
 195
 196 typedef struct watcher_timer_init_arg {
 197   state_watcher* w;
 198   gpr_timespec deadline;
 199 } watcher_timer_init_arg;
 200
 201 static void watcher_timer_init(void* arg, grpc_error* error_ignored) {
 202   watcher_timer_init_arg* wa = static_cast<watcher_timer_init_arg*>(arg);
 203
 204   grpc_timer_init(&wa->w->alarm, grpc_timespec_to_millis_round_up(wa->deadline),
 205                   &wa->w->on_timeout);
 206   gpr_free(wa);
 207 }
 208
 209 int grpc_channel_support_connectivity_watcher(grpc_channel* channel) {
 210   grpc_channel_element* client_channel_elem =
 211       grpc_channel_stack_last_element(grpc_channel_get_channel_stack(channel));
 212   return client_channel_elem->filter != &grpc_client_channel_filter ? 0 : 1;
 213 }
 214
 215 void grpc_channel_watch_connectivity_state(
 216     grpc_channel* channel, grpc_connectivity_state last_observed_state,
 217     gpr_timespec deadline, grpc_completion_queue* cq, void* tag) {
 218   grpc_channel_element* client_channel_elem =
 219       grpc_channel_stack_last_element(grpc_channel_get_channel_stack(channel));
 220   grpc_core::ApplicationCallbackExecCtx callback_exec_ctx;
 221   grpc_core::ExecCtx exec_ctx;
 222   state_watcher* w = static_cast<state_watcher*>(gpr_malloc(sizeof(*w)));
 223
 224   GRPC_API_TRACE(
 225       "grpc_channel_watch_connectivity_state("
 226       "channel=%p, last_observed_state=%d, "
 227       "deadline=gpr_timespec { tv_sec: %" PRId64
 228       ", tv_nsec: %d, clock_type: %d }, "
 229       "cq=%p, tag=%p)",
 230       7,
 231       (channel, (int)last_observed_state, deadline.tv_sec, deadline.tv_nsec,
 232        (int)deadline.clock_type, cq, tag));
 233
 234   GPR_ASSERT(grpc_cq_begin_op(cq, tag));
 235
 236   gpr_mu_init(&w->mu);
 237   GRPC_CLOSURE_INIT(&w->on_complete, watch_complete, w,
 238                     grpc_schedule_on_exec_ctx);
 239   GRPC_CLOSURE_INIT(&w->on_timeout, timeout_complete, w,
 240                     grpc_schedule_on_exec_ctx);
 241   w->phase = WAITING;
 242   w->state = last_observed_state;
 243   w->cq = cq;
 244   w->tag = tag;
 245   w->channel = channel;
 246   w->error = nullptr;
 247
 248   watcher_timer_init_arg* wa = static_cast<watcher_timer_init_arg*>(
 249       gpr_malloc(sizeof(watcher_timer_init_arg)));
 250   wa->w = w;
 251   wa->deadline = deadline;
 252   GRPC_CLOSURE_INIT(&w->watcher_timer_init, watcher_timer_init, wa,
 253                     grpc_schedule_on_exec_ctx);
 254
 255   if (client_channel_elem->filter == &grpc_client_channel_filter) {
 256     GRPC_CHANNEL_INTERNAL_REF(channel, "watch_channel_connectivity");
 257     grpc_client_channel_watch_connectivity_state(
 258         client_channel_elem,
 259         grpc_polling_entity_create_from_pollset(grpc_cq_pollset(cq)), &w->state,
 260         &w->on_complete, &w->watcher_timer_init);
 261   } else {
 262     abort();
 263   }
 264 }