Adds measurer middleware

middleware/request/measure.go

@@ -0,0 +1,26 @@
+package request
+
+import (
+	"time"
+
+	"github.com/ksysoev/wasabi"
+	"github.com/ksysoev/wasabi/dispatch"
+)
+
+// NewMeasurer returns a middleware function that measures the duration of each request and saves the metric using the provided `saveMetric` function.
+// The `saveMetric` function takes three parameters: the request, the error (if any), and the duration of the request.
+// The middleware function wraps the provided `next` request handler and measures the duration of the request by calculating the time elapsed between the start and end of the request.
+// After the request is handled, the metric is saved using the `saveMetric` function.
+// The middleware function returns the wrapped request handler.
+func NewMeasurer(saveMetric func(req wasabi.Request, err error, duration time.Duration)) func(next wasabi.RequestHandler) wasabi.RequestHandler {
+	return func(next wasabi.RequestHandler) wasabi.RequestHandler {
+		return dispatch.RequestHandlerFunc(func(conn wasabi.Connection, req wasabi.Request) error {
+			start := time.Now()
+			err := next.Handle(conn, req)
+			duration := time.Since(start)
+
+			saveMetric(req, err, duration)
+			return err
+		})
+	}
+}

middleware/request/measure_test.go

@@ -0,0 +1,57 @@
+package request
+
+import (
+	"testing"
+	"time"
+
+	"github.com/ksysoev/wasabi"
+	"github.com/ksysoev/wasabi/dispatch"
+	"github.com/ksysoev/wasabi/mocks"
+)
+
+func TestNewMeasurer(t *testing.T) {
+	// Define a mock saveMetric function
+	var savedMetric wasabi.Request
+	var savedError error
+	var savedDuration time.Duration
+	saveMetric := func(req wasabi.Request, err error, duration time.Duration) {
+		savedMetric = req
+		savedError = err
+		savedDuration = duration
+	}
+
+	// Define a mock request handler
+	mockHandler := dispatch.RequestHandlerFunc(func(conn wasabi.Connection, req wasabi.Request) error {
+		// Simulate some processing time
+		time.Sleep(100 * time.Microsecond)
+		return nil
+	})
+
+	// Create the measurer middleware
+	measurer := NewMeasurer(saveMetric)
+
+	// Create a mock connection and request
+	mockConn := mocks.NewMockConnection(t)
+	mockReq := mocks.NewMockRequest(t)
+
+	// Call the measurer middleware with the mock handler
+	err := measurer(mockHandler).Handle(mockConn, mockReq)
+
+	// Check if the metric was saved correctly
+	if savedMetric != mockReq {
+		t.Errorf("Expected saved metric to be %v, but got %v", mockReq, savedMetric)
+	}
+
+	if savedError != nil {
+		t.Errorf("Expected saved error to be nil, but got %v", savedError)
+	}
+
+	if savedDuration < 100*time.Microsecond {
+		t.Errorf("Expected saved duration to be greater than 100ms, but got %v", savedDuration)
+	}
+
+	// Check if the error is propagated correctly
+	if err != nil {
+		t.Errorf("Expected error to be nil, but got %v", err)
+	}
+}