Added a healthcheck to the OpenTelemetry Collector container (#858)

* Added a healthcheck to the OpenTelemetry Collector container

* Adding basic tests

* Added healthchecks to the otel collector

* Fixing some broken tests

---------

Co-authored-by: Aaron Powell <[email protected]>

Author: martinjt

src/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector/OpenTelemetryCollectorExtensions.cs

@@ -69,6 +69,18 @@ public static IResourceBuilder<OpenTelemetryCollectorResource> AddOpenTelemetryC
                     $@"--config=yaml:receivers::otlp::protocols::grpc::tls::key_file: ""{certKeyPath}""");
             }
         }
+
+        if (!settings.DisableHealthcheck)
+        {
+            const int healthPort = 13233;
+            resourceBuilder.WithEndpoint(targetPort: healthPort, name: "health", scheme: "http")
+                .WithHttpHealthCheck("/health", endpointName: "health")
+                .WithArgs(
+                    "--feature-gates=confmap.enableMergeAppendOption",
+                    $"--config=yaml:extensions::health_check/aspire::endpoint: 0.0.0.0:{healthPort}",
+                    "--config=yaml:service::extensions: [ health_check/aspire ]"
+                    );
+        }
         return resourceBuilder;
     }
 

src/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector/OpenTelemetryCollectorSettings.cs

@@ -43,4 +43,9 @@ public class OpenTelemetryCollectorSettings
     /// Note: this will also setup SSL if Aspire is configured for HTTPS
     /// </summary>
     public bool EnableHttpEndpoint { get; set; } = true;
+
+    /// <summary>
+    /// Disable the healthcheck on the collector container
+    /// </summary>
+    public bool DisableHealthcheck { get; set; } = false;
 }

tests/CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector.Tests/ResourceCreationTests.cs

@@ -30,7 +30,11 @@ public void CanCreateTheCollectorResource()
     public async Task CanCreateTheCollectorResourceWithCustomConfig()
     {
         var builder = DistributedApplication.CreateBuilder();
-        builder.AddOpenTelemetryCollector("collector")
+        builder.AddOpenTelemetryCollector("collector", settings =>
+        {
+
+            settings.DisableHealthcheck = true;
+        })
             .WithConfig("./config.yaml")
             .WithAppForwarding();
 
@@ -137,6 +141,7 @@ public void CanDisableBothEndpoints()
         {
             settings.EnableHttpEndpoint = false;
             settings.EnableGrpcEndpoint = false;
+            settings.DisableHealthcheck = true;
         })
             .WithAppForwarding();
 
@@ -157,7 +162,10 @@ public async Task ContainerHasAspireEnvironmentVariables()
             .WithTestAndResourceLogging(testOutputHelper);
         builder.Configuration["APPHOST:ContainerHostname"] = "what.ever";
 
-        var collector = builder.AddOpenTelemetryCollector("collector")
+        var collector = builder.AddOpenTelemetryCollector("collector", settings =>
+        {
+            settings.DisableHealthcheck = true;
+        })
             .WithAppForwarding();
 
         using var app = builder.Build();
@@ -259,6 +267,7 @@ public void CanConfigureOnlyGrpcEndpoint()
         {
             settings.EnableGrpcEndpoint = true;
             settings.EnableHttpEndpoint = false;
+            settings.DisableHealthcheck = true;
         })
             .WithAppForwarding();
 
@@ -285,6 +294,7 @@ public void CanConfigureOnlyHttpEndpoint()
         {
             settings.EnableGrpcEndpoint = false;
             settings.EnableHttpEndpoint = true;
+            settings.DisableHealthcheck = true;
         })
             .WithAppForwarding();
 
@@ -618,4 +628,48 @@ public void DevCertificateExecutableResourceHasCorrectConfiguration()
         Assert.Contains("Pem", argsContext.Args);
         Assert.Contains("--no-password", argsContext.Args);
     }
+
+    [Theory]
+    [InlineData(true)]
+    [InlineData(false)]
+    public void CanDisableHealthcheckOnCollectorResource(bool disableHealthcheck)
+    {
+        var builder = DistributedApplication.CreateBuilder();
+
+        builder.AddOpenTelemetryCollector("collector", settings =>
+        {
+            settings.DisableHealthcheck = disableHealthcheck;
+        })
+        .WithAppForwarding();
+
+        using var app = builder.Build();
+
+        var appModel = app.Services.GetRequiredService<DistributedApplicationModel>();
+
+        var collectorResource = appModel.Resources.OfType<OpenTelemetryCollectorResource>().SingleOrDefault();
+        Assert.NotNull(collectorResource);
+
+        var hasHealthCheck = collectorResource.Annotations.OfType<HealthCheckAnnotation>().Any();
+        if (disableHealthcheck)
+        {
+            Assert.False(hasHealthCheck);
+        }
+        else
+        {
+            Assert.True(hasHealthCheck);
+            var argsAnnotations = collectorResource.Annotations.OfType<CommandLineArgsCallbackAnnotation>().ToList();
+            Assert.NotEmpty(argsAnnotations);
+
+            var argsContext = new CommandLineArgsCallbackContext([]);
+            foreach (var arg in argsAnnotations)
+            {
+                arg.Callback(argsContext);
+            }
+
+            Assert.Contains("--feature-gates=confmap.enableMergeAppendOption", argsContext.Args);
+            Assert.Contains("--config=yaml:extensions::health_check/aspire::endpoint: 0.0.0.0:13233", argsContext.Args);
+            Assert.Contains("--config=yaml:service::extensions: [ health_check/aspire ]", argsContext.Args);
+        }
+
+    }
 }