API: Add health check endpoint

BTCPayServer.Client/BTCPayServerClient.Health.cs

@@ -0,0 +1,15 @@
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace BTCPayServer.Client
+{
+    public partial class BTCPayServerClient
+    {
+        public virtual async Task<bool> IsHealthy(CancellationToken token = default)
+        {
+            var response = await _httpClient.SendAsync(CreateHttpRequest("api/v1/health"), token);
+            return response.IsSuccessStatusCode;
+        }
+    }
+}

BTCPayServer.Tests/GreenfieldAPITests.cs

@@ -228,5 +228,19 @@ namespace BTCPayServer.Tests
 
             }
         }
+        
+        [Fact(Timeout = TestTimeout)]
+        [Trait("Integration", "Integration")]
+        public async Task HealthControllerTests()
+        {
+            using (var tester = ServerTester.Create())
+            {
+                await tester.StartAsync();
+                var unauthClient = new BTCPayServerClient(tester.PayTester.ServerUri);
+
+                var isHealthy = await unauthClient.IsHealthy();
+                Assert.True(isHealthy);
+            }
+        }
     }
 }

BTCPayServer/Controllers/GreenField/HealthController.cs

@@ -0,0 +1,16 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+
+namespace BTCPayServer.Controllers.GreenField
+{
+    [ApiController]
+    public class HealthController : ControllerBase
+    {
+        [AllowAnonymous]
+        [HttpGet("~/api/v1/health")]
+        public ActionResult GetHealth()
+        {
+            return Ok();
+        }
+    }
+}

BTCPayServer/wwwroot/swagger/v1/swagger.template.health.json

@@ -0,0 +1,26 @@
+{
+    "paths": {
+        "/api/v1/health": {
+            "get": {
+                "tags": [
+                    "Health"
+                ],
+                "summary": "Get health status",
+                "description": "Check whether of not the instance is up",
+                "operationId": "Health_GetHealth",
+                "responses": {
+                    "200": {
+                        "description": "Instance is up",
+                        "content": {}
+                    }
+                },
+                "security": []
+            }
+        }
+    },
+    "tags": [
+        {
+            "name": "Health"
+        }
+    ]
+}