Don't set exists watches if it is not necessary

vostok · Feb 2, 2024 · 7afb5a3 · 7afb5a3
1 parent c0b01c7
commit 7afb5a3
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Showing 8 changed files with 52 additions and 16 deletions.
diff --git a/Vostok.ServiceDiscovery.Tests/ServiceLocatorStorage/ApplicationsStorage_Tests.cs b/Vostok.ServiceDiscovery.Tests/ServiceLocatorStorage/ApplicationsStorage_Tests.cs
@@ -237,7 +237,7 @@ private static void ShouldReturnImmediately(ApplicationsStorage storage, string
 
         private ApplicationsStorage GetApplicationsStorage()
         {
-            return new ApplicationsStorage(ZooKeeperClient, PathHelper, EventsQueue, Log);
+            return new ApplicationsStorage(ZooKeeperClient, PathHelper, EventsQueue, true, Log);
         }
     }
 }
diff --git a/Vostok.ServiceDiscovery.Tests/ServiceLocatorStorage/EnvironmentsStorage_Tests.cs b/Vostok.ServiceDiscovery.Tests/ServiceLocatorStorage/EnvironmentsStorage_Tests.cs
@@ -168,7 +168,7 @@ private static void ShouldReturnImmediately(EnvironmentsStorage storage, string
 
         private EnvironmentsStorage GetEnvironmentsStorage()
         {
-            return new EnvironmentsStorage(ZooKeeperClient, PathHelper, EventsQueue, Log);
+            return new EnvironmentsStorage(ZooKeeperClient, PathHelper, EventsQueue, true, Log);
         }
     }
 }
diff --git a/Vostok.ServiceDiscovery/PublicAPI.Shipped.txt b/Vostok.ServiceDiscovery/PublicAPI.Shipped.txt
@@ -99,4 +99,6 @@ Vostok.ServiceDiscovery.ServiceLocatorSettings.ServiceLocatorSettings() -> void
 Vostok.ServiceDiscovery.ServiceLocatorSettings.ZooKeeperNodesPathEscaper.get -> Vostok.ServiceDiscovery.Helpers.IZooKeeperPathEscaper
 Vostok.ServiceDiscovery.ServiceLocatorSettings.ZooKeeperNodesPathEscaper.set -> void
 Vostok.ServiceDiscovery.ServiceLocatorSettings.ZooKeeperNodesPrefix.get -> string
-Vostok.ServiceDiscovery.ServiceLocatorSettings.ZooKeeperNodesPrefix.set -> void
+Vostok.ServiceDiscovery.ServiceLocatorSettings.ZooKeeperNodesPrefix.set -> void
+Vostok.ServiceDiscovery.ServiceLocatorSettings.ObserveNonExistentApplications.get -> bool
+Vostok.ServiceDiscovery.ServiceLocatorSettings.ObserveNonExistentApplications.set -> void
diff --git a/Vostok.ServiceDiscovery/ServiceLocator.cs b/Vostok.ServiceDiscovery/ServiceLocator.cs
@@ -44,9 +44,8 @@ public ServiceLocator(
             pathHelper = new ServiceDiscoveryPathHelper(this.settings.ZooKeeperNodesPrefix, this.settings.ZooKeeperNodesPathEscaper);
 
             eventsQueue = new ActionsQueue(this.log);
-            environmentsStorage = new EnvironmentsStorage(zooKeeperClient, pathHelper, eventsQueue, log);
-            applicationsStorage = new ApplicationsStorage(zooKeeperClient, pathHelper, eventsQueue, log);
-
+            environmentsStorage = new EnvironmentsStorage(zooKeeperClient, pathHelper, eventsQueue, this.settings.ObserveNonExistentApplications, log);
+            applicationsStorage = new ApplicationsStorage(zooKeeperClient, pathHelper, eventsQueue, this.settings.ObserveNonExistentApplications, log);
         }
 
         /// <inheritdoc />

diff --git a/Vostok.ServiceDiscovery/ServiceLocatorSettings.cs b/Vostok.ServiceDiscovery/ServiceLocatorSettings.cs
@@ -18,5 +18,7 @@ public class ServiceLocatorSettings
         public IZooKeeperPathEscaper ZooKeeperNodesPathEscaper { get; set; } = ZooKeeperPathEscaper.Instance;
 
         public TimeSpan IterationPeriod { get; set; } = 5.Seconds();
+
+        public bool ObserveNonExistentApplications { get; set; } = true;
     }
 }
diff --git a/Vostok.ServiceDiscovery/ServiceLocatorStorage/ApplicationWithReplicas.cs b/Vostok.ServiceDiscovery/ServiceLocatorStorage/ApplicationWithReplicas.cs
@@ -28,7 +28,9 @@ internal class ApplicationWithReplicas : IDisposable
         private readonly IZooKeeperClient zooKeeperClient;
         private readonly ServiceDiscoveryPathHelper pathHelper;
         private readonly ActionsQueue eventsQueue;
+        private readonly bool observeNonExistentApplication;
         private readonly AdHocNodeWatcher nodeWatcher;
+        private readonly AdHocNodeWatcher existsWatcher;
         private readonly ILog log;
         private readonly AtomicBoolean isDisposed = false;
 
@@ -39,6 +41,7 @@ public ApplicationWithReplicas(
             IZooKeeperClient zooKeeperClient,
             ServiceDiscoveryPathHelper pathHelper,
             ActionsQueue eventsQueue,
+            bool observeNonExistentApplication,
             ILog log)
         {
             this.environmentName = environmentName;
@@ -47,28 +50,33 @@ public ApplicationWithReplicas(
             this.zooKeeperClient = zooKeeperClient;
             this.pathHelper = pathHelper;
             this.eventsQueue = eventsQueue;
+            this.observeNonExistentApplication = observeNonExistentApplication;
             this.log = log;
 
             nodeWatcher = new AdHocNodeWatcher(OnNodeEvent);
+            existsWatcher = this.observeNonExistentApplication ? nodeWatcher : null;
             applicationContainer = new VersionedContainer<ApplicationInfo>();
             replicasContainer = new VersionedContainer<Uri[]>();
         }
 
-        public void Update()
+        public void Update(out bool appExists)
         {
+            appExists = true;
+
             if (isDisposed)
                 return;
 
             try
             {
-                var applicationExists = zooKeeperClient.Exists(new ExistsRequest(applicationNodePath) {Watcher = nodeWatcher});
+                var applicationExists = zooKeeperClient.Exists(new ExistsRequest(applicationNodePath) {Watcher = existsWatcher});
                 if (!applicationExists.IsSuccessful)
                 {
                     return;
                 }
 
                 if (applicationExists.Stat == null)
                 {
+                    appExists = false;
                     Clear();
                     return;
                 }
@@ -115,7 +123,7 @@ private void OnNodeEvent(NodeChangedEventType type, string path)
             if (isDisposed)
                 return;
 
-            eventsQueue.Enqueue(Update);
+            eventsQueue.Enqueue(() => Update(out _));
         }
 
         private void Clear()

diff --git a/Vostok.ServiceDiscovery/ServiceLocatorStorage/ApplicationsStorage.cs b/Vostok.ServiceDiscovery/ServiceLocatorStorage/ApplicationsStorage.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Concurrent;
+using System.Collections.Generic;
 using System.Runtime.CompilerServices;
 using System.Threading;
 using Vostok.Commons.Threading;
@@ -16,14 +17,21 @@ internal class ApplicationsStorage : IDisposable
         private readonly IZooKeeperClient zooKeeperClient;
         private readonly ServiceDiscoveryPathHelper pathHelper;
         private readonly ActionsQueue eventsQueue;
+        private readonly bool observeNonExistentApplications;
         private readonly ILog log;
         private readonly AtomicBoolean isDisposed = false;
 
-        public ApplicationsStorage(IZooKeeperClient zooKeeperClient, ServiceDiscoveryPathHelper pathHelper, ActionsQueue eventsQueue, ILog log)
+        public ApplicationsStorage(
+            IZooKeeperClient zooKeeperClient,
+            ServiceDiscoveryPathHelper pathHelper,
+            ActionsQueue eventsQueue,
+            bool observeNonExistentApplications,
+            ILog log)
         {
             this.zooKeeperClient = zooKeeperClient;
             this.pathHelper = pathHelper;
             this.eventsQueue = eventsQueue;
+            this.observeNonExistentApplications = observeNonExistentApplications;
             this.log = log;
         }
 
@@ -42,7 +50,9 @@ public void UpdateAll()
                 if (isDisposed)
                     return;
 
-                kvp.Value.Value.Update();
+                kvp.Value.Value.Update(out var appExists);
+                if (!appExists && !observeNonExistentApplications)
+                    applications.TryRemove(kvp.Key, out _);
             }
         }
 
@@ -64,9 +74,9 @@ private ApplicationWithReplicas CreateAndGet(string environment, string applicat
             lazy = new Lazy<ApplicationWithReplicas>(
                 () =>
                 {
-                    var container = new ApplicationWithReplicas(environment, application, pathHelper.BuildApplicationPath(environment, application), zooKeeperClient, pathHelper, eventsQueue, log);
+                    var container = new ApplicationWithReplicas(environment, application, pathHelper.BuildApplicationPath(environment, application), zooKeeperClient, pathHelper, eventsQueue, observeNonExistentApplications, log);
                     if (!isDisposed)
-                        container.Update();
+                        container.Update(out _);
                     return container;
                 },
                 LazyThreadSafetyMode.ExecutionAndPublication);

diff --git a/Vostok.ServiceDiscovery/ServiceLocatorStorage/EnvironmentsStorage.cs b/Vostok.ServiceDiscovery/ServiceLocatorStorage/EnvironmentsStorage.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Concurrent;
+using System.Collections.Generic;
 using System.Runtime.CompilerServices;
 using System.Threading;
 using Vostok.Commons.Threading;
@@ -20,17 +21,26 @@ private readonly ConcurrentDictionary<string, Lazy<VersionedContainer<Environmen
         private readonly IZooKeeperClient zooKeeperClient;
         private readonly ServiceDiscoveryPathHelper pathHelper;
         private readonly ActionsQueue eventsHandler;
+        private readonly bool observeNonExistentApplication;
         private readonly ILog log;
         private readonly AdHocNodeWatcher nodeWatcher;
+        private readonly AdHocNodeWatcher existsWatcher;
         private readonly AtomicBoolean isDisposed = new AtomicBoolean(false);
 
-        public EnvironmentsStorage(IZooKeeperClient zooKeeperClient, ServiceDiscoveryPathHelper pathHelper, ActionsQueue eventsHandler, ILog log)
+        public EnvironmentsStorage(
+            IZooKeeperClient zooKeeperClient,
+            ServiceDiscoveryPathHelper pathHelper,
+            ActionsQueue eventsHandler,
+            bool observeNonExistentApplication,
+            ILog log)
         {
             this.zooKeeperClient = zooKeeperClient;
             this.pathHelper = pathHelper;
             this.eventsHandler = eventsHandler;
+            this.observeNonExistentApplication = observeNonExistentApplication;
             this.log = log;
             nodeWatcher = new AdHocNodeWatcher(OnNodeEvent);
+            existsWatcher = this.observeNonExistentApplication ? nodeWatcher : null;
         }
 
         public EnvironmentInfo Get(string name)
@@ -92,13 +102,18 @@ private void Update(string name, VersionedContainer<EnvironmentInfo> container)
             try
             {
                 var environmentPath = pathHelper.BuildEnvironmentPath(name);
-
-                var environmentExists = zooKeeperClient.Exists(new ExistsRequest(environmentPath) {Watcher = nodeWatcher});
+                var environmentExists = zooKeeperClient.Exists(new ExistsRequest(environmentPath) {Watcher = existsWatcher});
                 if (!environmentExists.IsSuccessful)
                     return;
 
                 if (environmentExists.Stat == null)
                 {
+                    if (!observeNonExistentApplication)
+                    {
+                        environments.TryRemove(name, out _);
+                        return;
+                    }
+
                     container.Clear();
                 }
                 else