github.com/aacfactory/fns@v1.2.86-0.20240310083819-80d667fc0a17/transports/middlewares/latency/middleware.go (about)

     1  /*
     2   * Copyright 2023 Wang Min Xiang
     3   *
     4   * Licensed under the Apache License, Version 2.0 (the "License");
     5   * you may not use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   *
     8   * 	http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   *
    16   */
    17  
    18  package latency
    19  
    20  import (
    21  	"github.com/aacfactory/errors"
    22  	"github.com/aacfactory/fns/commons/bytex"
    23  	"github.com/aacfactory/fns/transports"
    24  	"time"
    25  )
    26  
    27  func Middleware() transports.Middleware {
    28  	return &middleware{}
    29  }
    30  
    31  type Config struct {
    32  	Enabled bool `json:"enabled"`
    33  }
    34  
    35  type middleware struct {
    36  	enabled bool
    37  }
    38  
    39  func (m *middleware) Name() string {
    40  	return "latency"
    41  }
    42  
    43  func (m *middleware) Construct(options transports.MiddlewareOptions) error {
    44  	config := Config{}
    45  	err := options.Config.As(&config)
    46  	if err != nil {
    47  		err = errors.Warning("fns: construct latency middleware failed").WithCause(err)
    48  		return err
    49  	}
    50  	m.enabled = config.Enabled
    51  	return nil
    52  }
    53  
    54  func (m *middleware) Handler(next transports.Handler) transports.Handler {
    55  	return transports.HandlerFunc(func(w transports.ResponseWriter, r transports.Request) {
    56  		beg := time.Time{}
    57  		if m.enabled {
    58  			beg = time.Now()
    59  		}
    60  		next.Handle(w, r)
    61  		if w.Hijacked() {
    62  			return
    63  		}
    64  		latency := time.Now().Sub(beg)
    65  		w.Header().Set(transports.HandleLatencyHeaderName, bytex.FromString(latency.String()))
    66  	})
    67  }
    68  
    69  func (m *middleware) Close() (err error) {
    70  	return
    71  }