github.com/mendersoftware/go-lib-micro@v0.0.0-20240304135804-e8e39c59b148/requestid/middleware.go (about)

     1  // Copyright 2023 Northern.tech AS
     2  //
     3  //	Licensed under the Apache License, Version 2.0 (the "License");
     4  //	you may not use this file except in compliance with the License.
     5  //	You may obtain a copy of the License at
     6  //
     7  //	    http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  //	Unless required by applicable law or agreed to in writing, software
    10  //	distributed under the License is distributed on an "AS IS" BASIS,
    11  //	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  //	See the License for the specific language governing permissions and
    13  //	limitations under the License.
    14  package requestid
    15  
    16  import (
    17  	"github.com/ant0ine/go-json-rest/rest"
    18  	"github.com/gin-gonic/gin"
    19  	"github.com/google/uuid"
    20  
    21  	"github.com/mendersoftware/go-lib-micro/log"
    22  	"github.com/mendersoftware/go-lib-micro/requestlog"
    23  )
    24  
    25  const RequestIdHeader = "X-MEN-RequestID"
    26  
    27  type MiddlewareOptions struct {
    28  	// GenerateRequestID decides whether a request ID should
    29  	// be generated when none exists. (default: true)
    30  	GenerateRequestID *bool
    31  }
    32  
    33  func NewMiddlewareOptions() *MiddlewareOptions {
    34  	return new(MiddlewareOptions)
    35  }
    36  
    37  func (opt *MiddlewareOptions) SetGenerateRequestID(gen bool) *MiddlewareOptions {
    38  	opt.GenerateRequestID = &gen
    39  	return opt
    40  }
    41  
    42  // Middleware provides requestid middleware for the gin-gonic framework.
    43  func Middleware(opts ...*MiddlewareOptions) gin.HandlerFunc {
    44  	opt := NewMiddlewareOptions().
    45  		SetGenerateRequestID(true)
    46  	for _, o := range opts {
    47  		if o == nil {
    48  			continue
    49  		}
    50  		if o.GenerateRequestID != nil {
    51  			opt.GenerateRequestID = o.GenerateRequestID
    52  		}
    53  	}
    54  	return func(c *gin.Context) {
    55  		ctx := c.Request.Context()
    56  
    57  		requestID := c.GetHeader(RequestIdHeader)
    58  		if requestID == "" && *opt.GenerateRequestID {
    59  			uid, _ := uuid.NewRandom()
    60  			requestID = uid.String()
    61  		}
    62  		ctx = WithContext(ctx, requestID)
    63  
    64  		logger := log.FromContext(ctx)
    65  		if logger != nil {
    66  			logger = logger.F(log.Ctx{"request_id": requestID})
    67  			ctx = log.WithContext(ctx, logger)
    68  		}
    69  		c.Header(RequestIdHeader, requestID)
    70  		c.Request = c.Request.WithContext(ctx)
    71  	}
    72  }
    73  
    74  // RequestIdMiddleware sets the X-MEN-RequestID header if it's not present, and and adds the request id to the request's logger's context.
    75  type RequestIdMiddleware struct {
    76  }
    77  
    78  // MiddlewareFunc makes RequestIdMiddleware implement the Middleware interface.
    79  func (mw *RequestIdMiddleware) MiddlewareFunc(h rest.HandlerFunc) rest.HandlerFunc {
    80  	return func(w rest.ResponseWriter, r *rest.Request) {
    81  		logger := requestlog.GetRequestLogger(r)
    82  
    83  		reqId := r.Header.Get(RequestIdHeader)
    84  		if reqId == "" {
    85  			uid, _ := uuid.NewRandom()
    86  			reqId = uid.String()
    87  		}
    88  
    89  		r = SetReqId(r, reqId)
    90  
    91  		// enrich log context
    92  		if logger != nil {
    93  			logger = logger.F(log.Ctx{"request_id": reqId})
    94  			r = requestlog.SetRequestLogger(r, logger)
    95  		}
    96  
    97  		//return the reuqest ID in response too, the client can log it
    98  		//for end-to-end req tracing
    99  		w.Header().Add(RequestIdHeader, reqId)
   100  
   101  		h(w, r)
   102  	}
   103  }