Begin adding health tracking integration, sync/bench harness support/…

…fix double use of blob wrapper

.cursorignore

@@ -0,0 +1,22 @@
+# Add directories or file patterns to ignore during indexing (e.g. foo/ or *.csv)
+*.txt
+*.dll
+*.pdb
+*.user
+*.png
+*.jpg
+*.jpeg
+*.bmp
+*.ico
+*.webp
+*.nupkg
+*.json
+*.info
+.idea/
+.vscode/
+bin/
+examples/
+NuGetPackages/
+obj/
+packages/
+

.vscode/settings.json

@@ -5,5 +5,10 @@
     ],
     "cSpell.ignoreWords": [
         "sthree"
-    ]
+    ],
+    "editor.fontSize": 14,
+    "window.zoomLevel": 1,
+    "window.zoomPerWindow": true,
+    "editor.mouseWheelZoom": true,
+    "terminal.integrated.mouseWheelZoom": true
 }

src/Imazen.Routing/Engine/RoutingEngine.cs

@@ -58,6 +58,12 @@ public bool MightHandleRequest<TQ>(string path, TQ query) where TQ : IReadOnlyQu
     }
 
 
+    /// <summary>
+    /// Errors if the route isn't a cachable blob; returns null if there's no match.
+    /// </summary>
+    /// <param name="request"></param>
+    /// <param name="cancellationToken"></param>
+    /// <returns></returns>
     public async ValueTask<CodeResult<ICacheableBlobPromise>?> RouteToPromiseAsync(MutableRequest request, CancellationToken cancellationToken = default)
     {
         // log info about the request

src/Imazen.Routing/Promises/Pipelines/CacheEngine.cs

@@ -8,6 +8,7 @@
 using Imazen.Abstractions.Resulting;
 using Imazen.Common.Concurrency;
 using Imazen.Common.Concurrency.BoundedTaskCollection;
+using Imazen.Routing.Health;
 using Imazen.Routing.Helpers;
 using Imazen.Routing.HttpAbstractions;
 using Imazen.Routing.Requests;
@@ -21,6 +22,7 @@ namespace Imazen.Routing.Promises.Pipelines;
 public class CacheEngine: IBlobPromisePipeline
 {
 
+
     public CacheEngine(IBlobPromisePipeline? next, CacheEngineOptions options)
     {
         Options = options;
@@ -30,6 +32,7 @@ public CacheEngine(IBlobPromisePipeline? next, CacheEngineOptions options)
         {
             Locks = new AsyncLockProvider();
         }
+        HealthTracker = options.HealthTracker as CacheHealthTracker;
     }
 
     public async ValueTask<CodeResult<ICacheableBlobPromise>> GetFinalPromiseAsync(ICacheableBlobPromise promise, IBlobRequestRouter router,
@@ -49,7 +52,7 @@ public async ValueTask<CodeResult<ICacheableBlobPromise>> GetFinalPromiseAsync(I
         return CodeResult<ICacheableBlobPromise>.Ok(
             new ServerlessCachePromise(wrappedPromise.FinalRequest, wrappedPromise, this));
     }
-
+    private CacheHealthTracker? HealthTracker { get; }
     private IBlobPromisePipeline? Next { get; }
     private AsyncLockProvider? Locks { get; }
 
@@ -70,7 +73,7 @@ private async Task FinishUpload(IBlobCacheRequest cacheReq, ICacheableBlobPromis
         await Task.WhenAll(Options.SaveToCaches.Select(x => x.CachePut(cacheEventDetails, cancellationToken)));
     }
 
-    public async ValueTask<CodeResult<IBlobWrapper>> Fetch(ICacheableBlobPromise promise,IBlobRequestRouter router,  CancellationToken cancellationToken = default)
+    internal async ValueTask<CodeResult<IBlobWrapper>> Fetch(ICacheableBlobPromise promise,IBlobRequestRouter router,  CancellationToken cancellationToken = default)
     {
         if (!promise.ReadyToWriteCacheKeyBasisData)
         {
@@ -95,16 +98,15 @@ public async ValueTask<CodeResult<IBlobWrapper>> Fetch(ICacheableBlobPromise pro
             return await FetchInner(cacheRequest, promise, router, cancellationToken);
         }
     }
-
 
-    
-    public async ValueTask<CodeResult<IBlobWrapper>> FetchInner(IBlobCacheRequest cacheRequest, ICacheableBlobPromise promise, IBlobRequestRouter router,  CancellationToken cancellationToken = default)
+
+    private async ValueTask<CodeResult<IBlobWrapper>> FetchInner(IBlobCacheRequest cacheRequest, ICacheableBlobPromise promise, IBlobRequestRouter router,  CancellationToken cancellationToken = default)
     {
         // First check the upload queue.
         if (Options.UploadQueue?.TryGet(cacheRequest.CacheKeyHashString, out var uploadTask) == true)
         {
             Options.Logger.LogTrace("Located requested resource from the upload queue {CacheKeyHashString}", cacheRequest.CacheKeyHashString);
-            return CodeResult<IBlobWrapper>.Ok(uploadTask.Blob);
+            return CodeResult<IBlobWrapper>.Ok(uploadTask.Blob.ForkReference());
         }
         // Then check the caches
         List<KeyValuePair<IBlobCache,Task<CacheFetchResult>>>? allFetchAttempts = null;
@@ -266,9 +268,9 @@ private void LogFetchTaskStatus(bool isFresh,
             LogFetchTaskStatus(isFresh, cacheHit, fetchTasks);
         }
 
-        if (Options.UploadQueue == null)
+        if (Options.UploadQueue == null && !Options.DelayRequestUntilUploadsComplete)
         {
-            Log.LogWarning("No upload queue configured");
+            Log.LogWarning("No upload queue configured, and synchronous mode disabled. Not saving to any caches.");
             return null;
         }
 
@@ -323,23 +325,27 @@ private void LogFetchTaskStatus(bool isFresh,
 
 
 
-    private async Task BufferAndEnqueueSaveToCaches(IBlobCacheRequest cacheRequest, IBlobWrapper blob, bool isFresh,
+    private async ValueTask BufferAndEnqueueSaveToCaches(IBlobCacheRequest cacheRequest, IBlobWrapper blob, bool isFresh,
         IBlobCache? cacheHit, List<KeyValuePair<IBlobCache, Task<CacheFetchResult>>>? fetchTasks, CancellationToken bufferCancellationToken = default)
     {
-        if (EnqueueSaveToCaches(cacheRequest, blob, isFresh, cacheHit, fetchTasks))
+        // Here's also a good place to handle the cachefetchresults; \
+        // HealthTracker[cacheHit].ReportBehavior();
+        //
+
+        if (await EnqueueSaveToCaches(cacheRequest, blob, isFresh, cacheHit, fetchTasks))
         {
             await blob.EnsureReusable(bufferCancellationToken);
             Log.LogTrace("Called EnsureReusable on {CacheKeyHashString}", cacheRequest.CacheKeyHashString);
         }
     }
 
-    private bool EnqueueSaveToCaches(IBlobCacheRequest cacheRequest, IBlobWrapper mainBlob, bool isFresh,
+    private ValueTask<bool> EnqueueSaveToCaches(IBlobCacheRequest cacheRequest, IBlobWrapper mainBlob, bool isFresh,
             IBlobCache? cacheHit, List<KeyValuePair<IBlobCache,Task<CacheFetchResult>>>? fetchTasks)
     {
 
         var cachesToSaveTo = GetUploadCacheCandidates(isFresh, ref cacheHit, fetchTasks);
 
-        if (cachesToSaveTo == null || Options.UploadQueue == null) return false; // Nothing to do
+        if (cachesToSaveTo == null || (Options.UploadQueue == null && !Options.DelayRequestUntilUploadsComplete)) return new ValueTask<bool>(false); // Nothing to do
 
         var blob = mainBlob.ForkReference();
         mainBlob.IndicateInterest();
@@ -360,39 +366,56 @@ private bool EnqueueSaveToCaches(IBlobCacheRequest cacheRequest, IBlobWrapper ma
             throw new InvalidOperationException();
         }
 
-
-        var enqueueResult = Options.UploadQueue.Queue(new BlobTaskItem(cacheRequest.CacheKeyHashString,blob), async (taskItem, cancellationToken) =>
+        var blobTaskItem = new BlobTaskItem(cacheRequest.CacheKeyHashString,blob);
+
+        Task<PutResult[]> BulkUploader(BlobTaskItem taskItem, CancellationToken cancellationToken)
         {
             // We need to dispose of the blob wrapper after all uploads are complete.
             using (taskItem.Blob)
             {
-                var tasks = cachesToSaveTo.Select(async cache =>
-                    {
-                        var waitingInQueue = DateTime.UtcNow - taskItem.JobCreatedAt;
+                var tasks = cachesToSaveTo.Select(PerCacheUpload)
+                    .ToArray();
+                return Task.WhenAll(tasks);
 
-                        var sw = Stopwatch.StartNew();
-                        try
-                        {
-                            Log.LogTrace("[put started] CachePut {key} to {CacheName}", taskItem.UniqueKey,
-                                cache.UniqueName);
-                            var result = await cache.CachePut(eventDetails, cancellationToken);
-                            sw.Stop();
-                            var r = new PutResult(cache, eventDetails, result, null, sw.Elapsed, waitingInQueue);
-                            LogPutResult(r);
-                            return r;
-                        }
-                        catch (Exception e)
-                        {
-                            sw.Stop();
-                            var r = new PutResult(cache, eventDetails, null, e, sw.Elapsed, waitingInQueue);
-                            LogPutResult(r);
-                            return r;
-                        }
+                async Task<PutResult> PerCacheUpload(IBlobCache cache)
+                {
+                    var waitingInQueue = DateTime.UtcNow - taskItem.JobCreatedAt;
+
+                    var sw = Stopwatch.StartNew();
+                    try
+                    {
+                        Log.LogTrace("[put started] CachePut {key} to {CacheName}", taskItem.UniqueKey, cache.UniqueName);
+                        var result = await cache.CachePut(eventDetails, cancellationToken);
+                        sw.Stop();
+                        var r = new PutResult(cache, eventDetails, result, null, sw.Elapsed, waitingInQueue);
+                        LogPutResult(r);
+                        return r;
                     }
-                ).ToArray();
-                HandleUploadAnswers(await Task.WhenAll(tasks));
+                    catch (Exception e)
+                    {
+                        sw.Stop();
+                        var r = new PutResult(cache, eventDetails, null, e, sw.Elapsed, waitingInQueue);
+                        LogPutResult(r);
+                        return r;
+                    }
+                }
             }
-        });
+        }
+
+        async Task BulkUploaderAsync(BlobTaskItem item, CancellationToken ct) => HandleUploadAnswers(await BulkUploader(item, ct));
+
+        if (Options.DelayRequestUntilUploadsComplete)
+        {
+            var uploadTask = BulkUploader(blobTaskItem, default);
+            var finalTask = uploadTask.ContinueWith(t =>
+            {
+                HandleUploadAnswers(t.Result);
+                return true;
+            }, TaskContinuationOptions.ExecuteSynchronously);
+            return new ValueTask<bool>(finalTask);
+        }
+        if (Options.UploadQueue == null) return new ValueTask<bool>(false);
+        var enqueueResult = Options.UploadQueue.Queue(blobTaskItem, BulkUploaderAsync);
         if (enqueueResult == TaskEnqueueResult.QueueFull)
         {
             Log.LogWarning("[CACHE PUT ERROR] Upload queue is full, not enqueuing {CacheKeyHashString} for upload to {Caches}", cacheRequest.CacheKeyHashString, string.Join(", ", cachesToSaveTo.Select(x => x.UniqueName)));
@@ -409,7 +432,8 @@ private bool EnqueueSaveToCaches(IBlobCacheRequest cacheRequest, IBlobWrapper ma
         {
             Log.LogTrace("Enqueued {CacheKeyHashString} for upload to {Caches}", cacheRequest.CacheKeyHashString, string.Join(", ", cachesToSaveTo.Select(x => x.UniqueName)));
         }
-        return enqueueResult == TaskEnqueueResult.Enqueued;
+
+        return new ValueTask<bool>(enqueueResult == TaskEnqueueResult.Enqueued);
     }
     record struct PutResult(IBlobCache Cache, CacheEventDetails EventDetails, CodeResult? Result, Exception? Exception, TimeSpan Executing, TimeSpan Waiting);
 
@@ -432,13 +456,9 @@ private void LogPutResult(PutResult result)
 
     private void HandleUploadAnswers(PutResult[] results)
     {
-        //TODO? 
+        //TODO? Cache put failures should probably affect health??
 
     }
-
-
-
-
 }
 
 internal record ServerlessCachePromise(IRequestSnapshot FinalRequest, ICacheableBlobPromise FreshPromise, CacheEngine CacheEngine): ICacheableBlobPromise

src/Imazen.Routing/Promises/Pipelines/CacheEngineOptions.cs

@@ -2,6 +2,7 @@
 using Imazen.Abstractions.Blobs;
 using Imazen.Abstractions.Logging;
 using Imazen.Common.Concurrency.BoundedTaskCollection;
+using Imazen.Routing.Health;
 using Imazen.Routing.Requests;
 
 namespace Imazen.Routing.Promises.Pipelines;
@@ -20,15 +21,21 @@ public CacheEngineOptions(List<IBlobCache> simultaneousFetchAndPut, BoundedTaskC
     // Each cache group is a list of caches that can be queried in parallel
     public required List<List<IBlobCache>> SeriesOfCacheGroups { get; init; }
 
+    // All caches we want to enable writing to
     public required List<IBlobCache> SaveToCaches { get; init; }
 
-    [Obsolete("Use the parameterized one local to the request")]
-    public IBlobRequestRouter? RequestRouter { get; init; }
-
+    // TODO: maybe remove?
     public required IReusableBlobFactory BlobFactory { get; init; }
 
     public required BoundedTaskCollection<BlobTaskItem>? UploadQueue { get; init; }
 
+    public required object? HealthTracker { get; init; }
+
+    /// <summary>
+    /// Disables background upload queue, and instead uploads blobs immediately before responding to the client.
+    /// </summary>
+    public bool DelayRequestUntilUploadsComplete { get; init; }
+
     public required IReLogger Logger { get; init; }
 
     /// <summary>
@@ -40,6 +47,4 @@ public CacheEngineOptions(List<IBlobCache> simultaneousFetchAndPut, BoundedTaskC
     /// How long to wait for fetching and generation of the same request by another thread.
     /// </summary>
     public int LockTimeoutMs { get; init; } = 2000;
-
-
 }

src/Imazen.Routing/Serving/ImageServer.cs

@@ -12,6 +12,7 @@
 using Imazen.Common.Licensing;
 using Imazen.Routing.Caching;
 using Imazen.Routing.Engine;
+using Imazen.Routing.Health;
 using Imazen.Routing.Helpers;
 using Imazen.Routing.HttpAbstractions;
 using Imazen.Routing.Layers;
@@ -37,6 +38,7 @@ internal class ImageServer<TRequest, TResponse, TContext> : IImageServer<TReques
     private readonly BoundedTaskCollection<BlobTaskItem> uploadQueue;
     private readonly bool shutdownRegisteredServices;
     private readonly IImageServerContainer container;
+    private readonly CacheHealthTracker cacheHealthTracker;
     public ImageServer(IImageServerContainer container,  
         ILicenseChecker licenseChecker,
         LicenseOptions licenseOptions,
@@ -95,11 +97,15 @@ public ImageServer(IImageServerContainer container,
         }
 
         var allCachesExceptMemory = allCaches?.Where(c => c != memoryCache)?.ToList();
+
+        cacheHealthTracker = container.GetService<CacheHealthTracker>();
+        cacheHealthTracker ??= new CacheHealthTracker(logger);
 
         var watermarkingLogic = container.GetService<WatermarkingLogicOptions>() ??
                                 new WatermarkingLogicOptions(null, null);
         var sourceCacheOptions = new CacheEngineOptions
         {
+            HealthTracker = cacheHealthTracker,
             SeriesOfCacheGroups =
             [
                 ..new[] { [memoryCache], allCachesExceptMemory ?? [] }
@@ -304,16 +310,18 @@ await SmallHttpResponse.Text(404, "The specified resource does not exist.\r\n" +
 
     }
 
-    public Task StartAsync(CancellationToken cancellationToken)
+    public async Task StartAsync(CancellationToken cancellationToken)
     {
-        return uploadQueue.StartAsync(cancellationToken);
+        await uploadQueue.StartAsync(cancellationToken);
+        await cacheHealthTracker.StartAsync(cancellationToken);
     }
 
     public async Task StopAsync(CancellationToken cancellationToken)
     {
         //TODO: error handling or no?
         //await uploadCancellationTokenSource.CancelAsync();
         await uploadQueue.StopAsync(cancellationToken);
+        await cacheHealthTracker.StopAsync(cancellationToken);
         if (shutdownRegisteredServices)
         {
             var services = this.container.GetInstanceOfEverythingLocal<IHostedService>();