rename metrics to meter

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

meter/wrapper/metrics_wrapper.go

@@ -0,0 +1,50 @@
+package wrapper
+
+import (
+	"context"
+	"time"
+
+	"github.com/unistack-org/micro/v3/metadata"
+	"github.com/unistack-org/micro/v3/meter"
+	"github.com/unistack-org/micro/v3/server"
+)
+
+// Wrapper provides a HandlerFunc for meter.Reporter implementations:
+type Wrapper struct {
+	reporter meter.Reporter
+}
+
+// New returns a *Wrapper configured with the given meter.Reporter:
+func New(reporter meter.Reporter) *Wrapper {
+	return &Wrapper{
+		reporter: reporter,
+	}
+}
+
+// HandlerFunc instruments handlers registered to a service:
+func (w *Wrapper) HandlerFunc(handlerFunction server.HandlerFunc) server.HandlerFunc {
+	return func(ctx context.Context, req server.Request, rsp interface{}) error {
+
+		// Build some tags to describe the call:
+		tags := metadata.New(2)
+		tags.Set("method", req.Method())
+
+		// Start the clock:
+		callTime := time.Now()
+
+		// Run the handlerFunction:
+		err := handlerFunction(ctx, req, rsp)
+
+		// Add a result tag:
+		if err != nil {
+			tags["status"] = "failure"
+		} else {
+			tags["status"] = "success"
+		}
+
+		// Instrument the result (if the DefaultClient has been configured):
+		w.reporter.Timing("service.handler", time.Since(callTime), tags)
+
+		return err
+	}
+}