Fix bug where tracing span name isnt set (#480)

This fixes an issue where the Tracing middleware wasn't updating the span name with the correct endpoint path when using RouterBuilder

Sources/Hummingbird/Middleware/TracingMiddleware.swift

@@ -43,12 +43,8 @@ public struct TracingMiddleware<Context: RequestContext>: RouterMiddleware {
         var serviceContext = ServiceContext.current ?? ServiceContext.topLevel
         InstrumentationSystem.instrument.extract(request.headers, into: &serviceContext, using: HTTPHeadersExtractor())
 
-        let operationName: String = {
-            guard let endpointPath = context.endpointPath else {
-                return "HTTP \(request.method.rawValue) route not found"
-            }
-            return endpointPath
-        }()
+        // span name is updated after route has run
+        let operationName = "HTTP \(request.method.rawValue) route not found"
 
         let span = InstrumentationSystem.tracer.startSpan(operationName, context: serviceContext, ofKind: .server)
         span.updateAttributes { attributes in
@@ -85,6 +81,9 @@ public struct TracingMiddleware<Context: RequestContext>: RouterMiddleware {
         do {
             return try await ServiceContext.$current.withValue(span.context) {
                 var response = try await next(request, context)
+                if let endpointPath = context.endpointPath {
+                    span.operationName = endpointPath
+                }
                 span.updateAttributes { attributes in
                     attributes = self.recordHeaders(response.headers, toSpanAttributes: attributes, withPrefix: "http.response.header.")
 
@@ -98,6 +97,9 @@ public struct TracingMiddleware<Context: RequestContext>: RouterMiddleware {
                 return response
             }
         } catch {
+            if let endpointPath = context.endpointPath {
+                span.operationName = endpointPath
+            }
             let statusCode = (error as? HTTPResponseError)?.status.code ?? 500
             span.attributes["http.status_code"] = statusCode
             if 500..<600 ~= statusCode {

Tests/HummingbirdTests/TracingTests.swift

@@ -14,6 +14,7 @@
 
 import HTTPTypes
 import Hummingbird
+import HummingbirdRouter
 import HummingbirdTesting
 @testable import Instrumentation
 import Tracing
@@ -67,6 +68,44 @@ final class TracingTests: XCTestCase {
         ])
     }
 
+    func testTracingMiddlewareWithRouterBuilder() async throws {
+        let expectation = expectation(description: "Expected span to be ended.")
+
+        let tracer = TestTracer()
+        tracer.onEndSpan = { _ in expectation.fulfill() }
+        InstrumentationSystem.bootstrapInternal(tracer)
+
+        let router = RouterBuilder(context: BasicRouterRequestContext.self) {
+            TracingMiddleware(attributes: ["net.host.name": "127.0.0.1", "net.host.port": 8080])
+            Get("users/{id}") { _, _ in "42" }
+        }
+        let app = Application(responder: router.buildResponder())
+        try await app.test(.router) { client in
+            try await client.execute(uri: "/users/42", method: .get) { response in
+                XCTAssertEqual(response.status, .ok)
+                XCTAssertEqual(String(buffer: response.body), "42")
+            }
+        }
+
+        await self.wait(for: [expectation], timeout: 1)
+
+        let span = try XCTUnwrap(tracer.spans.first)
+
+        XCTAssertEqual(span.operationName, "/users/{id}")
+        XCTAssertEqual(span.kind, .server)
+        XCTAssertNil(span.status)
+        XCTAssertTrue(span.recordedErrors.isEmpty)
+
+        XCTAssertSpanAttributesEqual(span.attributes, [
+            "http.method": "GET",
+            "http.target": "/users/42",
+            "http.status_code": 200,
+            "http.response_content_length": 2,
+            "net.host.name": "127.0.0.1",
+            "net.host.port": 8080,
+        ])
+    }
+
     func testTracingMiddlewareServerError() async throws {
         let expectation = expectation(description: "Expected span to be ended.")