feat(engine): RetentionService — hourly executions sweep

src/VolcanicCore.Api/Engine/RetentionService.cs

@@ -0,0 +1,52 @@
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+using VolcanicCore.Persistence.Repositories;
+
+namespace VolcanicCore.Api.Engine;
+
+public sealed class RetentionService : BackgroundService
+{
+    private static readonly TimeSpan SweepInterval = TimeSpan.FromHours(1);
+
+    private readonly ExecutionRepository _executions;
+    private readonly int _retentionDays;
+    private readonly int _keepPerWorkflow;
+    private readonly ILogger<RetentionService> _log;
+
+    public RetentionService(
+        ExecutionRepository executions, int retentionDays, int keepPerWorkflow, ILogger<RetentionService> log)
+    {
+        _executions = executions;
+        _retentionDays = retentionDays;
+        _keepPerWorkflow = keepPerWorkflow;
+        _log = log;
+    }
+
+    // Public so tests can invoke it deterministically.
+    public void RunSweep()
+    {
+        try
+        {
+            var oldCutoff = DateTimeOffset.UtcNow.AddDays(-_retentionDays);
+            var byAge = _executions.PruneOlderThan(oldCutoff);
+            var overCap = _executions.PruneOldestPerWorkflow(_keepPerWorkflow);
+            _log.LogInformation("retention sweep: pruned {ByAge} by age, {OverCap} by per-workflow cap",
+                byAge, overCap);
+        }
+        catch (Exception ex)
+        {
+            _log.LogError(ex, "retention sweep failed");
+        }
+    }
+
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        RunSweep();
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            try { await Task.Delay(SweepInterval, stoppingToken); }
+            catch (TaskCanceledException) { break; }
+            RunSweep();
+        }
+    }
+}

src/VolcanicCore.Api/Program.cs

@@ -125,6 +125,12 @@ builder.Services.AddSingleton<TriggerHost>();
 builder.Services.AddSingleton<IWorkflowLifecycle>(sp => sp.GetRequiredService<TriggerHost>());
 builder.Services.AddHostedService(sp => sp.GetRequiredService<TriggerHost>());
 
+builder.Services.AddHostedService(sp => new RetentionService(
+    sp.GetRequiredService<ExecutionRepository>(),
+    settings.ExecutionRetentionDays,
+    settings.ExecutionKeepPerWorkflow,
+    sp.GetRequiredService<ILogger<RetentionService>>()));
+
 var app = builder.Build();
 
 // Apply migrations at boot.

tests/VolcanicCore.Tests/RetentionServiceTests.cs

@@ -0,0 +1,43 @@
+using Microsoft.Extensions.Logging.Abstractions;
+using VolcanicCore.Api.Engine;
+using VolcanicCore.Persistence;
+using VolcanicCore.Persistence.Migrations;
+using VolcanicCore.Persistence.Repositories;
+
+namespace VolcanicCore.Tests;
+
+public class RetentionServiceTests
+{
+    [Fact]
+    public void Sweep_prunes_old_rows_and_over_cap_rows()
+    {
+        var path = Path.Combine(Path.GetTempPath(), $"vc-{Guid.NewGuid():N}.db");
+        var f = new SqliteConnectionFactory(path);
+        using (var conn = f.Open())
+            new Migrator(new IMigration[]
+            {
+                new Migration001Initial(), new Migration002Connections(), new Migration003Workflows(),
+                new Migration004Executions(), new Migration005NodeExecutions(),
+            }).Apply(conn);
+        var er = new ExecutionRepository(f);
+
+        // 3 old finished, 5 recent finished (keep=3 → prune 2 of the recent + all 3 old)
+        for (var i = 0; i < 3; i++)
+        {
+            var id = er.Create("wf", "manual", "{}");
+            er.SetStatus(id, "completed", null, DateTimeOffset.UtcNow.AddDays(-30));
+        }
+        for (var i = 0; i < 5; i++)
+        {
+            var id = er.Create("wf", "manual", "{}");
+            er.SetStatus(id, "completed", null, DateTimeOffset.UtcNow.AddSeconds(i));
+        }
+        Assert.Equal(8, er.ListForWorkflow("wf", 100).Count);
+
+        var svc = new RetentionService(er, retentionDays: 7, keepPerWorkflow: 3,
+            NullLogger<RetentionService>.Instance);
+        svc.RunSweep();
+
+        Assert.Equal(3, er.ListForWorkflow("wf", 100).Count);
+    }
+}