WaitFor support for Garnet.

src/Aspire.Hosting.Garnet/Aspire.Hosting.Garnet.csproj

@@ -18,6 +18,10 @@
     <Compile Include="$(SharedDir)VolumeNameGenerator.cs" Link="Utils\VolumeNameGenerator.cs" />
   </ItemGroup>
 
+  <ItemGroup>
+    <PackageReference Include="AspNetCore.HealthChecks.Redis" />
+  </ItemGroup>
+
   <ItemGroup>
     <ProjectReference Include="..\Aspire.Hosting\Aspire.Hosting.csproj" />
   </ItemGroup>

src/Aspire.Hosting.Garnet/GarnetBuilderExtensions.cs

@@ -5,6 +5,7 @@
 using Aspire.Hosting.ApplicationModel;
 using Aspire.Hosting.Garnet;
 using Aspire.Hosting.Utils;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Aspire.Hosting;
 
@@ -55,10 +56,27 @@ public static IResourceBuilder<GarnetResource> AddGarnet(this IDistributedApplic
         ArgumentNullException.ThrowIfNull(name);
 
         var garnet = new GarnetResource(name);
+
+        string? connectionString = null;
+
+        builder.Eventing.Subscribe<ConnectionStringAvailableEvent>(garnet, async (@event, ct) =>
+        {
+            connectionString = await garnet.ConnectionStringExpression.GetValueAsync(ct).ConfigureAwait(false);
+
+            if (connectionString == null)
+            {
+                throw new DistributedApplicationException($"ConnectionStringAvailableEvent was published for the '{garnet.Name}' resource but the connection string was null.");
+            }
+        });
+
+        var healthCheckKey = $"{name}_check";
+        builder.Services.AddHealthChecks().AddRedis(sp => connectionString ?? throw new InvalidOperationException("Connection string is unavailable"), name: healthCheckKey);
+
         return builder.AddResource(garnet)
             .WithEndpoint(port: port, targetPort: 6379, name: GarnetResource.PrimaryEndpointName)
             .WithImage(GarnetContainerImageTags.Image, GarnetContainerImageTags.Tag)
-            .WithImageRegistry(GarnetContainerImageTags.Registry);
+            .WithImageRegistry(GarnetContainerImageTags.Registry)
+            .WithHealthCheck(healthCheckKey);
     }
 
     /// <summary>

tests/Aspire.Hosting.Garnet.Tests/GarnetFunctionalTests.cs

@@ -2,9 +2,11 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using Aspire.Components.Common.Tests;
+using Aspire.Hosting.ApplicationModel;
 using Aspire.Hosting.Utils;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Diagnostics.HealthChecks;
 using Microsoft.Extensions.Hosting;
 using Polly;
 using StackExchange.Redis;
@@ -15,6 +17,46 @@ namespace Aspire.Hosting.Garnet.Tests;
 
 public class GarnetFunctionalTests(ITestOutputHelper testOutputHelper)
 {
+    [Fact]
+    [RequiresDocker]
+    public async Task VerifyWaitForOnGarnetBlocksDependentResources()
+    {
+        var cts = new CancellationTokenSource(TimeSpan.FromMinutes(3));
+        using var builder = TestDistributedApplicationBuilder.Create().WithTestAndResourceLogging(testOutputHelper);
+
+        var healthCheckTcs = new TaskCompletionSource<HealthCheckResult>();
+        builder.Services.AddHealthChecks().AddAsyncCheck("blocking_check", () =>
+        {
+            return healthCheckTcs.Task;
+        });
+
+        var resource = builder.AddGarnet("resource")
+                              .WithHealthCheck("blocking_check");
+
+        var dependentResource = builder.AddGarnet("dependentresource")
+                                       .WaitFor(resource);
+
+        using var app = builder.Build();
+
+        var pendingStart = app.StartAsync(cts.Token);
+
+        var rns = app.Services.GetRequiredService<ResourceNotificationService>();
+
+        await rns.WaitForResourceAsync(resource.Resource.Name, KnownResourceStates.Running, cts.Token);
+
+        await rns.WaitForResourceAsync(dependentResource.Resource.Name, KnownResourceStates.Waiting, cts.Token);
+
+        healthCheckTcs.SetResult(HealthCheckResult.Healthy());
+
+        await rns.WaitForResourceAsync(resource.Resource.Name, (re => re.Snapshot.HealthStatus == HealthStatus.Healthy), cts.Token);
+
+        await rns.WaitForResourceAsync(dependentResource.Resource.Name, KnownResourceStates.Running, cts.Token);
+
+        await pendingStart;
+
+        await app.StopAsync();
+    }
+
     [Fact]
     [RequiresDocker]
     public async Task VerifyGarnetResource()