github.com/m3db/m3@v1.5.0/src/query/api/v1/middleware/source.go (about)

     1  // Copyright (c) 2021 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package middleware
    22  
    23  import (
    24  	"fmt"
    25  	"net/http"
    26  
    27  	"github.com/gorilla/mux"
    28  	"go.uber.org/zap"
    29  
    30  	"github.com/m3db/m3/src/query/source"
    31  	"github.com/m3db/m3/src/query/util/logging"
    32  	"github.com/m3db/m3/src/x/headers"
    33  	xhttp "github.com/m3db/m3/src/x/net/http"
    34  )
    35  
    36  var errInvalidSourceHeader = xhttp.NewError(
    37  	fmt.Errorf("invalid %s header", headers.SourceHeader),
    38  	http.StatusBadRequest)
    39  
    40  // SourceOptions are the options for the source middleware.
    41  type SourceOptions struct {
    42  	Deserializer source.Deserializer
    43  }
    44  
    45  // Source adds the headers.SourceHeader value to the request context.
    46  // Installing this middleware function allows application code to access the typed source value using FromContext.
    47  // Additionally a source log field is added to the request scope logger.
    48  func Source(opts Options) mux.MiddlewareFunc {
    49  	return func(base http.Handler) http.Handler {
    50  		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    51  			hs := r.Header.Get(headers.SourceHeader)
    52  			if len(hs) == 0 {
    53  				// bail early if the header is not set on the request.
    54  				base.ServeHTTP(w, r)
    55  				return
    56  			}
    57  			iOpts := opts.InstrumentOpts
    58  			s := []byte(hs)
    59  			ctx := logging.NewContext(r.Context(), iOpts, zap.ByteString("source", s))
    60  			l := logging.WithContext(ctx, iOpts)
    61  			ctx, err := source.NewContext(ctx, s, opts.Source.Deserializer)
    62  			if err != nil {
    63  				l.Error("failed to deserialize source", zap.Error(err))
    64  				xhttp.WriteError(w, errInvalidSourceHeader)
    65  				return
    66  			}
    67  			base.ServeHTTP(w, r.WithContext(ctx))
    68  		})
    69  	}
    70  }