Add watchers lock

src/csharp/Grpc.HealthCheck/HealthServiceImpl.cs

@@ -39,7 +39,9 @@ namespace Grpc.HealthCheck
     /// </summary>
     public class HealthServiceImpl : Grpc.Health.V1.Health.HealthBase
     {
-        private readonly object myLock = new object();
+        private readonly object statusLock = new object();
+        private readonly object watchersLock = new object();
+
         private readonly Dictionary<string, HealthCheckResponse.Types.ServingStatus> statusMap =
             new Dictionary<string, HealthCheckResponse.Types.ServingStatus>();
         private readonly Dictionary<string, List<IServerStreamWriter<HealthCheckResponse>>> watchers =
@@ -52,15 +54,16 @@ namespace Grpc.HealthCheck
         /// <param name="status">the health status</param>
         public void SetStatus(string service, HealthCheckResponse.Types.ServingStatus status)
         {
-            lock (myLock)
+            HealthCheckResponse.Types.ServingStatus previousStatus;
+            lock (statusLock)
             {
-                HealthCheckResponse.Types.ServingStatus previousStatus = GetServiceStatus(service);
+                previousStatus = GetServiceStatus(service);
                 statusMap[service] = status;
+            }
 
-                if (status != previousStatus)
+            if (status != previousStatus)
-                {
+            {
-                    NotifyStatus(service, status);
+                NotifyStatus(service, status);
-                }
             }
         }
 
@@ -70,15 +73,16 @@ namespace Grpc.HealthCheck
         /// <param name="service">The service. Cannot be null.</param>
         public void ClearStatus(string service)
         {
-            lock (myLock)
+            HealthCheckResponse.Types.ServingStatus previousStatus;
+            lock (statusLock)
             {
-                HealthCheckResponse.Types.ServingStatus previousStatus = GetServiceStatus(service);
+                previousStatus = GetServiceStatus(service);
                 statusMap.Remove(service);
+            }
 
-                if (previousStatus != HealthCheckResponse.Types.ServingStatus.ServiceUnknown)
+            if (previousStatus != HealthCheckResponse.Types.ServingStatus.ServiceUnknown)
-                {
+            {
-                    NotifyStatus(service, HealthCheckResponse.Types.ServingStatus.ServiceUnknown);
+                NotifyStatus(service, HealthCheckResponse.Types.ServingStatus.ServiceUnknown);
-                }
             }
         }
 
@@ -87,18 +91,18 @@ namespace Grpc.HealthCheck
         /// </summary>
         public void ClearAll()
         {
-            lock (myLock)
+            List<KeyValuePair<string, HealthCheckResponse.Types.ServingStatus>> statuses;
+            lock (statusLock)
             {
-                List<KeyValuePair<string, HealthCheckResponse.Types.ServingStatus>> statuses = statusMap.ToList();
+                statuses = statusMap.ToList();
-
                 statusMap.Clear();
+            }
 
-                foreach (KeyValuePair<string, HealthCheckResponse.Types.ServingStatus> status in statuses)
+            foreach (KeyValuePair<string, HealthCheckResponse.Types.ServingStatus> status in statuses)
+            {
+                if (status.Value != HealthCheckResponse.Types.ServingStatus.ServiceUnknown)
                 {
-                    if (status.Value != HealthCheckResponse.Types.ServingStatus.Unknown)
+                    NotifyStatus(status.Key, HealthCheckResponse.Types.ServingStatus.ServiceUnknown);
-                    {
-                        NotifyStatus(status.Key, HealthCheckResponse.Types.ServingStatus.Unknown);
-                    }
                 }
             }
         }
@@ -145,7 +149,7 @@ namespace Grpc.HealthCheck
             HealthCheckResponse response = GetHealthCheckResponse(service, throwOnNotFound: false);
             await responseStream.WriteAsync(response);
 
-            lock (myLock)
+            lock (watchersLock)
             {
                 if (!watchers.TryGetValue(service, out List<IServerStreamWriter<HealthCheckResponse>> serverStreamWriters))
                 {
@@ -158,7 +162,7 @@ namespace Grpc.HealthCheck
 
             // Handle the Watch call being canceled
             context.CancellationToken.Register(() => {
-                lock (myLock)
+                lock (watchersLock)
                 {
                     if (watchers.TryGetValue(service, out List<IServerStreamWriter<HealthCheckResponse>> serverStreamWriters))
                     {
@@ -185,7 +189,7 @@ namespace Grpc.HealthCheck
         private HealthCheckResponse GetHealthCheckResponse(string service, bool throwOnNotFound)
         {
             HealthCheckResponse response = null;
-            lock (myLock)
+            lock (statusLock)
             {
                 HealthCheckResponse.Types.ServingStatus status;
                 if (!statusMap.TryGetValue(service, out status))
@@ -220,14 +224,17 @@ namespace Grpc.HealthCheck
 
         private void NotifyStatus(string service, HealthCheckResponse.Types.ServingStatus status)
         {
-            if (watchers.TryGetValue(service, out List<IServerStreamWriter<HealthCheckResponse>> serverStreamWriters))
+            lock (watchersLock)
             {
-                HealthCheckResponse response = new HealthCheckResponse { Status = status };
+                if (watchers.TryGetValue(service, out List<IServerStreamWriter<HealthCheckResponse>> serverStreamWriters))
-
-                foreach (IServerStreamWriter<HealthCheckResponse> serverStreamWriter in serverStreamWriters)
                 {
-                    // TODO(JamesNK): This will fail if a pending write is already in progress.
+                    HealthCheckResponse response = new HealthCheckResponse { Status = status };
-                    _ = serverStreamWriter.WriteAsync(response);
+
+                    foreach (IServerStreamWriter<HealthCheckResponse> serverStreamWriter in serverStreamWriters)
+                    {
+                        // TODO(JamesNK): This will fail if a pending write is already in progress.
+                        _ = serverStreamWriter.WriteAsync(response);
+                    }
                 }
             }
         }