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/*
*
* Copyright 2015 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#include "src/core/ext/filters/client_channel/connectivity_watcher.h"
#include <grpc/grpc.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/sync.h>
#include "src/core/ext/filters/client_channel/channel_connectivity_internal.h"
#include "src/core/ext/filters/client_channel/client_channel.h"
#include "src/core/lib/iomgr/timer.h"
#include "src/core/lib/support/env.h"
#include "src/core/lib/support/string.h"
#include "src/core/lib/surface/channel.h"
#include "src/core/lib/surface/completion_queue.h"
#define DEFAULT_CONNECTIVITY_CHECK_INTERVAL_MS 500
typedef struct connectivity_watcher {
grpc_timer watcher_timer;
grpc_closure check_connectivity_closure;
grpc_completion_queue* cq;
gpr_refcount refs;
size_t channel_count;
bool shutting_down;
} connectivity_watcher;
typedef struct channel_state {
grpc_channel_element* client_channel_elem;
grpc_channel_stack* channel_stack;
grpc_connectivity_state state;
} channel_state;
static gpr_once g_once = GPR_ONCE_INIT;
static gpr_mu g_watcher_mu;
static connectivity_watcher* g_watcher = NULL;
static void init_g_watcher_mu() { gpr_mu_init(&g_watcher_mu); }
static void start_watching_locked(grpc_exec_ctx* exec_ctx,
grpc_channel_element* client_channel_elem,
grpc_channel_stack* channel_stack) {
gpr_ref(&g_watcher->refs);
++g_watcher->channel_count;
channel_state* s = (channel_state*)gpr_zalloc(sizeof(channel_state));
s->client_channel_elem = client_channel_elem;
s->channel_stack = channel_stack;
s->state = GRPC_CHANNEL_IDLE;
grpc_channel_watch_connectivity_state_internal(
exec_ctx, client_channel_elem, channel_stack, s->state,
gpr_inf_future(GPR_CLOCK_MONOTONIC), g_watcher->cq, (void*)s);
}
static bool is_disabled() {
char* env = gpr_getenv("GRPC_DISABLE_CHANNEL_CONNECTIVITY_WATCHER");
bool disabled = gpr_is_true(env);
gpr_free(env);
return disabled;
}
static bool connectivity_watcher_unref(grpc_exec_ctx* exec_ctx) {
if (gpr_unref(&g_watcher->refs)) {
gpr_mu_lock(&g_watcher_mu);
grpc_completion_queue_destroy(g_watcher->cq);
gpr_free(g_watcher);
g_watcher = NULL;
gpr_mu_unlock(&g_watcher_mu);
return true;
}
return false;
}
static void check_connectivity_state(grpc_exec_ctx* exec_ctx, void* ignored,
grpc_error* error) {
grpc_event ev;
while (true) {
gpr_mu_lock(&g_watcher_mu);
if (g_watcher->shutting_down) {
// Drain cq if the watcher is shutting down
ev = grpc_completion_queue_next(
g_watcher->cq, gpr_inf_future(GPR_CLOCK_MONOTONIC), NULL);
} else {
ev = grpc_completion_queue_next(g_watcher->cq,
gpr_inf_past(GPR_CLOCK_MONOTONIC), NULL);
// Make sure we've seen 2 TIMEOUTs before going to sleep
if (ev.type == GRPC_QUEUE_TIMEOUT) {
ev = grpc_completion_queue_next(
g_watcher->cq, gpr_inf_past(GPR_CLOCK_MONOTONIC), NULL);
if (ev.type == GRPC_QUEUE_TIMEOUT) {
gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
grpc_timer_init(
exec_ctx, &g_watcher->watcher_timer,
gpr_time_add(now, gpr_time_from_millis(
DEFAULT_CONNECTIVITY_CHECK_INTERVAL_MS,
GPR_TIMESPAN)),
&g_watcher->check_connectivity_closure, now);
gpr_mu_unlock(&g_watcher_mu);
break;
}
}
}
gpr_mu_unlock(&g_watcher_mu);
if (ev.type != GRPC_OP_COMPLETE) {
break;
}
channel_state* s = (channel_state*)(ev.tag);
s->state = grpc_client_channel_check_connectivity_state(
exec_ctx, s->client_channel_elem, false /* try_to_connect */);
if (s->state == GRPC_CHANNEL_SHUTDOWN) {
GRPC_CHANNEL_STACK_UNREF(exec_ctx, s->channel_stack,
"connectivity_watcher_stop_watching");
gpr_free(s);
if (connectivity_watcher_unref(exec_ctx)) {
break;
}
} else {
grpc_channel_watch_connectivity_state_internal(
exec_ctx, s->client_channel_elem, s->channel_stack, s->state,
gpr_inf_future(GPR_CLOCK_MONOTONIC), g_watcher->cq, s);
}
}
}
void grpc_client_channel_start_watching_connectivity(
grpc_exec_ctx* exec_ctx, grpc_channel_element* client_channel_elem,
grpc_channel_stack* channel_stack) {
if (is_disabled()) return;
GRPC_CHANNEL_STACK_REF(channel_stack, "connectivity_watcher_start_watching");
gpr_once_init(&g_once, init_g_watcher_mu);
gpr_mu_lock(&g_watcher_mu);
if (g_watcher == NULL) {
g_watcher = (connectivity_watcher*)gpr_zalloc(sizeof(connectivity_watcher));
g_watcher->cq = grpc_completion_queue_create_internal(
GRPC_CQ_NEXT, GRPC_CQ_DEFAULT_POLLING);
gpr_ref_init(&g_watcher->refs, 0);
GRPC_CLOSURE_INIT(&g_watcher->check_connectivity_closure,
check_connectivity_state, NULL,
grpc_schedule_on_exec_ctx);
gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
grpc_timer_init(
exec_ctx, &g_watcher->watcher_timer,
gpr_time_add(
now, gpr_time_from_millis(DEFAULT_CONNECTIVITY_CHECK_INTERVAL_MS,
GPR_TIMESPAN)),
&g_watcher->check_connectivity_closure, now);
}
start_watching_locked(exec_ctx, client_channel_elem, channel_stack);
gpr_mu_init(&g_watcher_mu);
}
void grpc_client_channel_stop_watching_connectivity(
grpc_exec_ctx* exec_ctx, grpc_channel_element* client_channel_elem,
grpc_channel_stack* channel_stack) {
if (is_disabled()) return;
gpr_once_init(&g_once, init_g_watcher_mu);
gpr_mu_lock(&g_watcher_mu);
if (--g_watcher->channel_count == 0) {
g_watcher->shutting_down = true;
grpc_timer_cancel(exec_ctx, &g_watcher->watcher_timer);
connectivity_watcher_unref(exec_ctx);
}
gpr_mu_unlock(&g_watcher_mu);
}
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