From ce9ea55b90f0d2c3306e5f06b51bd75802a5cd4c Mon Sep 17 00:00:00 2001
From: Richard Pringle <richardpringle@gmail.com>
Date: Tue, 7 Feb 2023 18:50:05 +0800
Subject: [PATCH] Simulated health check (#116)

Co-authored-by: Richard Pringle <richard.pringle@gmail.com>
---
 .../IntegrationTests/BasicTests.cs              | 17 +++++++++++++++++
 .../Controllers/HealthController.cs             | 14 ++++++++++++++
 .../Middleware/EventGridMiddleware.cs           | 17 +++++++++++++++++
 3 files changed, 48 insertions(+)
 create mode 100644 src/AzureEventGridSimulator/Controllers/HealthController.cs

diff --git a/src/AzureEventGridSimulator.Tests/IntegrationTests/BasicTests.cs b/src/AzureEventGridSimulator.Tests/IntegrationTests/BasicTests.cs
index 4e99f12..5354875 100644
--- a/src/AzureEventGridSimulator.Tests/IntegrationTests/BasicTests.cs
+++ b/src/AzureEventGridSimulator.Tests/IntegrationTests/BasicTests.cs
@@ -51,4 +51,21 @@ public async Task GivenAValidEvent_WhenPublished_ThenItShouldBeAccepted()
         response.EnsureSuccessStatusCode();
         response.StatusCode.ShouldBe(HttpStatusCode.OK);
     }
+
+    [Fact]
+    public async Task GivenAHealthRequest_ThenItShouldRespondWithOk()
+    {
+        // Arrange
+        var client = _factory.CreateClient(new WebApplicationFactoryClientOptions
+        {
+            BaseAddress = new Uri("https://localhost:60101")
+        });
+
+        // Act
+        var response = await client.GetAsync("/api/health");
+
+        // Assert
+        response.StatusCode.ShouldBe(HttpStatusCode.OK);
+        (await response.Content.ReadAsStringAsync()).ShouldBe("OK");
+    }
 }
diff --git a/src/AzureEventGridSimulator/Controllers/HealthController.cs b/src/AzureEventGridSimulator/Controllers/HealthController.cs
new file mode 100644
index 0000000..8e9909f
--- /dev/null
+++ b/src/AzureEventGridSimulator/Controllers/HealthController.cs
@@ -0,0 +1,14 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace AzureEventGridSimulator.Controllers;
+
+[Route("/api/health")]
+[ApiController]
+public class HealthController : ControllerBase
+{
+    [HttpGet]
+    public IActionResult Get()
+    {
+        return Ok("OK");
+    }
+}
diff --git a/src/AzureEventGridSimulator/Infrastructure/Middleware/EventGridMiddleware.cs b/src/AzureEventGridSimulator/Infrastructure/Middleware/EventGridMiddleware.cs
index 839d7a0..d1efea6 100644
--- a/src/AzureEventGridSimulator/Infrastructure/Middleware/EventGridMiddleware.cs
+++ b/src/AzureEventGridSimulator/Infrastructure/Middleware/EventGridMiddleware.cs
@@ -38,6 +38,12 @@ public async Task InvokeAsync(HttpContext context,
             return;
         }
 
+        if (IsHealthRequest(context))
+        {
+            await ValidateHealthRequest(context);
+            return;
+        }
+
         // This is the end of the line.
         await context.WriteErrorResponse(HttpStatusCode.BadRequest, "Request not supported.", null);
     }
@@ -129,6 +135,11 @@ private async Task ValidateNotificationRequest(HttpContext context,
         await _next(context);
     }
 
+    private async Task ValidateHealthRequest(HttpContext context)
+    {
+        await _next(context);
+    }
+
     private static bool IsNotificationRequest(HttpContext context)
     {
         return context.Request.Headers.Keys.Any(k => string.Equals(k, "Content-Type", StringComparison.OrdinalIgnoreCase)) &&
@@ -144,4 +155,10 @@ private static bool IsValidationRequest(HttpContext context)
                context.Request.Query.Keys.Any(k => string.Equals(k, "id", StringComparison.OrdinalIgnoreCase)) &&
                Guid.TryParse(context.Request.Query["id"], out _);
     }
+
+    private static bool IsHealthRequest(HttpContext context)
+    {
+        return context.Request.Method == HttpMethods.Get &&
+            string.Equals(context.Request.Path, "/api/health", StringComparison.OrdinalIgnoreCase);
+    }
 }