health_check_using_rpc: refine code

src/brpc/details/health_check.cpp

@@ -68,7 +68,12 @@ public:
 
 class HealthCheckManager {
 public:
-    static void StartCheck(SocketId id, int64_t check_interval_s) {
+    static void StartCheck(SocketId id, int64_t check_interval_s);
+    static void* AppCheck(void* arg);
+    static void RunAppCheck(void* arg);
+};
+
+void HealthCheckManager::StartCheck(SocketId id, int64_t check_interval_s) {
     SocketUniquePtr ptr;
     const int rc = Socket::AddressFailedAsWell(id, &ptr);
     if (rc < 0) {
@@ -93,9 +98,9 @@ public:
         return;
     }
     AppCheck(done);
-    }
+}
 
-    static void* AppCheck(void* arg) {
+void* HealthCheckManager::AppCheck(void* arg) {
     OnAppHealthCheckDone* done = static_cast<OnAppHealthCheckDone*>(arg);
     done->cntl.Reset();
     done->cntl.http_request().uri() = FLAGS_health_check_path;
@@ -103,9 +108,9 @@ public:
     done->last_check_time_ms = butil::gettimeofday_ms();
     done->channel.CallMethod(NULL, &done->cntl, NULL, NULL, done);
     return NULL;
-    }
+}
 
-    static void RunAppCheck(void* arg) {
+void HealthCheckManager::RunAppCheck(void* arg) {
     bthread_t th = 0;
     int rc = bthread_start_background(
         &th, &BTHREAD_ATTR_NORMAL, AppCheck, arg);
@@ -114,8 +119,7 @@ public:
         AppCheck(arg);
         return;
     }
-    }
-};
+}
 
 void OnAppHealthCheckDone::Run() {
     std::unique_ptr<OnAppHealthCheckDone> self_guard(this);
@@ -129,6 +133,8 @@ void OnAppHealthCheckDone::Run() {
     if (!cntl.Failed() || ptr->Failed()) {
         LOG_IF(INFO, !cntl.Failed()) << "Succeeded to call "
             << ptr->remote_side() << FLAGS_health_check_path;
+        // if ptr->Failed(), previous SetFailed would trigger next round
+        // of hc, just return here.
         ptr->_ninflight_app_health_check.fetch_sub(
                     1, butil::memory_order_relaxed);
         return;
@@ -145,6 +151,9 @@ void OnAppHealthCheckDone::Run() {
                 &timer_id, abstime, HealthCheckManager::RunAppCheck, this);
         if (rc != 0) {
             LOG(ERROR) << "Fail to add timer for RunAppCheck";
+            // TODO(zhujiashun): we need to handle the case when timer fails.
+            // In most situations, the possibility of this case is quite small,
+            // so currently we just keep sending the hc call.
             HealthCheckManager::AppCheck(this);
             return;
         }