Add health checks to OTLP service (#18)

A new constant, ExposeHealthChecks, was added to OtlpLiterals.cs to allow the toggling of health checks through the environment variable "OTEL_EXPOSE_HEALTHCHECKS". Also, MapDefaultEndpoints method was added to OtlpServiceExtensions.cs to map health check endpoints if ExposeHealthChecks is enabled.

src/SimCube.Aspire/Features/Otlp/OtlpLiterals.cs

@@ -6,4 +6,5 @@ public static class OtlpLiterals
     public const string Headers = "OTEL_EXPORTER_OTLP_HEADERS";
     public const string ResourceAttributes = "OTEL_RESOURCE_ATTRIBUTES";
     public const string ServiceName = "OTEL_SERVICE_NAME";
-}
+    public const string ExposeHealthChecks = "OTEL_EXPOSE_HEALTHCHECKS";
+}

src/SimCube.Aspire/Features/Otlp/OtlpServiceExtensions.cs

@@ -56,6 +56,21 @@ public static LoggerConfiguration GetLoggerConfiguration(this IConfiguration con
 
         return config;
     }
+
+    public static void MapDefaultEndpoints(this WebApplication app)
+    {
+        if (string.IsNullOrEmpty(Environment.GetEnvironmentVariable("OTEL_EXPOSE_HEALTHCHECKS")))
+        {
+            return;
+        }
+
+        app.MapHealthChecks("/health");
+
+        app.MapHealthChecks("/alive", new()
+        {
+            Predicate = r => r.Tags.Contains("live")
+        });
+    }
 
     private static void ConfigureSerilog(this IHostApplicationBuilder builder)
     {