propagate shared-config and library-option changes between instances

Add a Redis pub/sub invalidation bus, publish from the configuration and library-option write paths, and drop the matching local cache entry on the instances that did not write. No-op without a Redis connection string, and fails open when it is unreachable.
2026-09-20 23:47:21 +10:00
parent ec581b5e5f
commit b662ffa48f
16 changed files with 919 additions and 1 deletions
@@ -0,0 +1,147 @@
+using System;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using Emby.Server.Implementations;
+using Emby.Server.Implementations.Configuration;
+using Emby.Server.Implementations.Serialization;
+using MediaBrowser.Common.Configuration;
+using MediaBrowser.Common.Net;
+using MediaBrowser.Controller.Configuration;
+using Microsoft.Extensions.Logging.Abstractions;
+using StackExchange.Redis;
+using Xunit;
+
+namespace Jellyfin.Server.Implementations.Tests.Configuration;
+
+/// <summary>
+/// Two independently constructed <see cref="ServerConfigurationManager"/> instances over one configuration
+/// directory are the in-process stand-in for two replicas sharing one <c>/config</c> mount: what either of
+/// them writes, the other has to pick up without being restarted.
+/// </summary>
+public sealed class SharedConfigurationPropagationTests : IDisposable
+{
+    private readonly string _root;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="SharedConfigurationPropagationTests"/> class.
+    /// </summary>
+    public SharedConfigurationPropagationTests()
+    {
+        _root = Path.Combine(Path.GetTempPath(), "jf-config-prop-" + Guid.NewGuid().ToString("N"));
+        Directory.CreateDirectory(_root);
+    }
+
+    /// <inheritdoc />
+    public void Dispose()
+    {
+        try
+        {
+            Directory.Delete(_root, true);
+        }
+        catch (IOException)
+        {
+        }
+    }
+
+    /// <summary>
+    /// A system configuration setting tightened on one replica has to hold on every other replica, not
+    /// only on the one that served the admin's request.
+    /// </summary>
+    /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+    [Fact]
+    public async Task SystemConfigurationSavedOnOneInstance_IsSeenByAnotherWithoutRestart()
+    {
+        var fabric = new FakeInvalidationBusFabric();
+        var instanceA = CreateInstance(fabric, "pod-a");
+        var instanceB = await CreateSubscribedInstanceAsync(fabric, "pod-b");
+
+        // B has the pre-change configuration in hand before A writes, as a running replica would.
+        Assert.True(instanceB.Configuration.QuickConnectAvailable);
+
+        instanceA.Configuration.QuickConnectAvailable = false;
+        instanceA.SaveConfiguration();
+
+        Assert.False(instanceB.Configuration.QuickConnectAvailable);
+    }
+
+    /// <summary>
+    /// The same has to hold for the named configurations, which are cached per key and never reloaded.
+    /// </summary>
+    /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+    [Fact]
+    public async Task NamedConfigurationSavedOnOneInstance_IsSeenByAnotherWithoutRestart()
+    {
+        var fabric = new FakeInvalidationBusFabric();
+        var instanceA = CreateInstance(fabric, "pod-a");
+        var instanceB = await CreateSubscribedInstanceAsync(fabric, "pod-b");
+
+        Assert.True(instanceB.GetNetworkConfiguration().EnableRemoteAccess);
+
+        var updated = instanceA.GetNetworkConfiguration();
+        updated.EnableRemoteAccess = false;
+        instanceA.SaveConfiguration(NetworkConfigurationStore.StoreKey, updated);
+
+        Assert.False(instanceB.GetNetworkConfiguration().EnableRemoteAccess);
+    }
+
+    /// <summary>
+    /// A replica that cannot reach the bus keeps serving: the admin's save still lands on the shared
+    /// directory, and the only loss is that the other replicas are not told about it.
+    /// </summary>
+    [Fact]
+    public void SaveConfiguration_WithUnreachableBus_DoesNotThrow()
+    {
+        using var multiplexer = ConnectionMultiplexer.Connect("127.0.0.1:1,abortConnect=false,connectTimeout=200,connectRetry=1,syncTimeout=200");
+        var bus = new RedisConfigurationInvalidationBus(multiplexer, NullLogger<RedisConfigurationInvalidationBus>.Instance);
+
+        bus.Subscribe(_ => throw new InvalidOperationException("Nothing can be delivered by an unreachable bus."));
+
+        var instance = CreateInstance(new FakeInvalidationBusFabric(), "pod-a");
+        instance.InvalidationBus = bus;
+
+        instance.Configuration.QuickConnectAvailable = false;
+        instance.SaveConfiguration();
+        instance.SaveConfiguration(NetworkConfigurationStore.StoreKey, instance.GetNetworkConfiguration());
+
+        Assert.False(instance.Configuration.QuickConnectAvailable);
+    }
+
+    private async Task<ServerConfigurationManager> CreateSubscribedInstanceAsync(FakeInvalidationBusFabric fabric, string originId)
+    {
+        var instance = CreateInstance(fabric, originId);
+        var subscriber = new ConfigurationInvalidationSubscriber(
+            instance.InvalidationBus,
+            instance,
+            NullLogger<ConfigurationInvalidationSubscriber>.Instance);
+
+        await subscriber.StartAsync(CancellationToken.None);
+        return instance;
+    }
+
+    private ServerConfigurationManager CreateInstance(FakeInvalidationBusFabric fabric, string originId)
+    {
+        // Every instance has its own paths object, all of them pointing at the one shared directory.
+        var paths = new ServerApplicationPaths(
+            Ensure("data"),
+            Ensure("log"),
+            Ensure("config"),
+            Ensure("cache"),
+            Ensure("web"));
+
+        var manager = new ServerConfigurationManager(paths, NullLoggerFactory.Instance, new MyXmlSerializer())
+        {
+            InvalidationBus = fabric.Connect(originId)
+        };
+
+        manager.AddParts([new NetworkConfigurationFactory()]);
+        return manager;
+    }
+
+    private string Ensure(string name)
+    {
+        var path = Path.Combine(_root, name);
+        Directory.CreateDirectory(path);
+        return path;
+    }
+}