[#149] Move middlewares to separate package

Signed-off-by: Denis Kirillov <d.kirillov@yadro.com>

api/middleware/middleware.go

@@ -0,0 +1,27 @@
+package middleware
+
+import (
+	"context"
+	"net/http"
+
+	"go.uber.org/zap"
+)
+
+type Func func(h http.Handler) http.Handler
+
+func WrapHandler(handler http.HandlerFunc) Func {
+	return func(h http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			handler(w, r)
+			h.ServeHTTP(w, r)
+		})
+	}
+}
+
+func reqLogOrDefault(ctx context.Context, log *zap.Logger) *zap.Logger {
+	reqLog := GetReqLog(ctx)
+	if reqLog != nil {
+		return reqLog
+	}
+	return log
+}