Add ITranscodeSessionStore interface and HA recovery unit tests (#19)

* Initial plan * Add ITranscodeSessionStore interface, TranscodeSession record, InMemoryTranscodeSessionStore fake, and HA unit tests" Co-authored-by: ZoltyMat <177592743+ZoltyMat@users.noreply.github.com> --------- Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: ZoltyMat <177592743+ZoltyMat@users.noreply.github.com>
2026-03-09 22:35:32 -04:00
parent cf5268c1e4
commit a187ab18b8
6 changed files with 756 additions and 0 deletions
@@ -0,0 +1,167 @@
+using System;
+using System.Threading.Tasks;
+using Jellyfin.MediaEncoding.Tests.Fakes;
+using MediaBrowser.Controller.MediaEncoding;
+using Xunit;
+
+namespace Jellyfin.MediaEncoding.Tests.Transcoding;
+
+/// <summary>
+/// Unit tests for the HA session-store contract: lease expiry, double-claim prevention,
+/// heartbeat renewal, and stale-session cleanup.
+/// All tests exercise <see cref="InMemoryTranscodeSessionStore"/> which implements the
+/// <see cref="ITranscodeSessionStore"/> interface that will be backed by Redis in Phase 5.2.
+/// </summary>
+public class TranscodeManagerTests
+{
+    private static TranscodeSession CreateSession(
+        string id,
+        string pod,
+        DateTime leaseExpiry,
+        int lastSegmentIndex = 0,
+        long lastOffset = 0L)
+        => new TranscodeSession
+        {
+            PlaySessionId = id,
+            OwnerPod = pod,
+            LeaseExpiresUtc = leaseExpiry,
+            ManifestPath = $"/transcode/{id}/manifest.m3u8",
+            SegmentPathPrefix = $"/transcode/{id}/segment",
+            MediaSourceId = $"media-source-{id}",
+            LastCompletedSegmentIndex = lastSegmentIndex,
+            LastDurablePlaybackOffset = lastOffset,
+        };
+
+    /// <summary>
+    /// Lease expiry: <see cref="ITranscodeSessionStore.TryGetAsync"/> returns <c>null</c>
+    /// once <see cref="TranscodeSession.LeaseExpiresUtc"/> has passed.
+    /// </summary>
+    [Fact]
+    [Trait("Category", "UnitTest")]
+    public async Task TryGetAsync_AfterLeaseExpires_ReturnsNull()
+    {
+        var store = new InMemoryTranscodeSessionStore();
+        var session = CreateSession("session-expired", "pod-a", DateTime.UtcNow.AddMilliseconds(-1));
+        await store.SetAsync(session);
+
+        var result = await store.TryGetAsync("session-expired");
+
+        Assert.Null(result);
+    }
+
+    /// <summary>
+    /// A session whose lease has not yet expired is returned correctly.
+    /// </summary>
+    [Fact]
+    [Trait("Category", "UnitTest")]
+    public async Task TryGetAsync_WithinLease_ReturnsSession()
+    {
+        var store = new InMemoryTranscodeSessionStore();
+        var session = CreateSession("session-live", "pod-a", DateTime.UtcNow.AddMinutes(5), lastSegmentIndex: 3, lastOffset: 18_000_000L);
+        await store.SetAsync(session);
+
+        var result = await store.TryGetAsync("session-live");
+
+        Assert.NotNull(result);
+        Assert.Equal("session-live", result.PlaySessionId);
+        Assert.Equal("pod-a", result.OwnerPod);
+        Assert.Equal(3, result.LastCompletedSegmentIndex);
+        Assert.Equal(18_000_000L, result.LastDurablePlaybackOffset);
+    }
+
+    /// <summary>
+    /// Double-claim prevention: <see cref="ITranscodeSessionStore.TryTakeoverAsync"/> returns
+    /// <c>false</c> while the first pod's lease is still valid.
+    /// </summary>
+    [Fact]
+    [Trait("Category", "UnitTest")]
+    public async Task TryTakeoverAsync_WhileLeaseValid_ReturnsFalse()
+    {
+        var store = new InMemoryTranscodeSessionStore();
+        var session = CreateSession("session-valid", "pod-a", DateTime.UtcNow.AddMinutes(5));
+        await store.SetAsync(session);
+
+        var firstAttempt = await store.TryTakeoverAsync("session-valid", "pod-b");
+        var secondAttempt = await store.TryTakeoverAsync("session-valid", "pod-c");
+
+        Assert.False(firstAttempt);
+        Assert.False(secondAttempt);
+    }
+
+    /// <summary>
+    /// After a lease expires, the first concurrent caller that invokes
+    /// <see cref="ITranscodeSessionStore.TryTakeoverAsync"/> wins; the second caller returns <c>false</c>.
+    /// </summary>
+    [Fact]
+    [Trait("Category", "UnitTest")]
+    public async Task TryTakeoverAsync_AfterLeaseExpires_OnlyFirstClaimerSucceeds()
+    {
+        var store = new InMemoryTranscodeSessionStore();
+        var session = CreateSession("session-stale", "pod-a", DateTime.UtcNow.AddMilliseconds(-1));
+        await store.SetAsync(session);
+
+        // First pod wins; its takeover renews the lease atomically.
+        var firstTakeover = await store.TryTakeoverAsync("session-stale", "pod-b");
+
+        // Second pod is too late – pod-b already holds a fresh lease.
+        var secondTakeover = await store.TryTakeoverAsync("session-stale", "pod-c");
+
+        Assert.True(firstTakeover);
+        Assert.False(secondTakeover);
+    }
+
+    /// <summary>
+    /// Heartbeat renewal: <see cref="ITranscodeSessionStore.RenewLeaseAsync"/> extends
+    /// <see cref="TranscodeSession.LeaseExpiresUtc"/> beyond its original value.
+    /// </summary>
+    [Fact]
+    [Trait("Category", "UnitTest")]
+    public async Task RenewLeaseAsync_ExtendsLeaseExpiry()
+    {
+        var store = new InMemoryTranscodeSessionStore();
+        var originalExpiry = DateTime.UtcNow.AddSeconds(5);
+        var session = CreateSession("session-renew", "pod-a", originalExpiry, lastSegmentIndex: 2, lastOffset: 10_000_000L);
+        await store.SetAsync(session);
+
+        await store.RenewLeaseAsync("session-renew");
+
+        var renewed = await store.TryGetAsync("session-renew");
+        Assert.NotNull(renewed);
+        Assert.True(
+            renewed.LeaseExpiresUtc > originalExpiry,
+            "Renewed lease expiry should be later than the original expiry.");
+    }
+
+    /// <summary>
+    /// Stale-session cleanup: an expired session can be deleted without error, and a
+    /// subsequent <see cref="ITranscodeSessionStore.TryGetAsync"/> returns <c>null</c>.
+    /// </summary>
+    [Fact]
+    [Trait("Category", "UnitTest")]
+    public async Task DeleteAsync_ExpiredSession_CompletesWithoutError()
+    {
+        var store = new InMemoryTranscodeSessionStore();
+        var session = CreateSession("session-delete", "pod-a", DateTime.UtcNow.AddMilliseconds(-1));
+        await store.SetAsync(session);
+
+        var ex = await Record.ExceptionAsync(() => store.DeleteAsync("session-delete"));
+        Assert.Null(ex);
+
+        var result = await store.TryGetAsync("session-delete");
+        Assert.Null(result);
+    }
+
+    /// <summary>
+    /// Deleting a session that was never stored must complete without error.
+    /// </summary>
+    [Fact]
+    [Trait("Category", "UnitTest")]
+    public async Task DeleteAsync_NonExistentSession_CompletesWithoutError()
+    {
+        var store = new InMemoryTranscodeSessionStore();
+
+        var ex = await Record.ExceptionAsync(() => store.DeleteAsync("nonexistent-session"));
+
+        Assert.Null(ex);
+    }
+}