github.com/google/martian/v3@v3.3.3/api/forwarder.go (about)

     1  // Copyright 2016 Google Inc. All rights reserved.
     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  
    15  // Package api contains a forwarder to route system HTTP requests to the
    16  // local API server.
    17  package api
    18  
    19  import (
    20  	"fmt"
    21  	"net/http"
    22  
    23  	"github.com/google/martian/v3"
    24  	"github.com/google/martian/v3/log"
    25  )
    26  
    27  // Forwarder is a request modifier that routes the request to the API server and
    28  // marks the request for skipped logging.
    29  type Forwarder struct {
    30  	host string
    31  	port int
    32  }
    33  
    34  // NewForwarder returns a Forwarder that rewrites requests to host.
    35  func NewForwarder(host string, port int) *Forwarder {
    36  	if host == "" {
    37  		host = "localhost"
    38  	}
    39  	return &Forwarder{
    40  		host: host,
    41  		port: port,
    42  	}
    43  }
    44  
    45  // ModifyRequest forwards the request to the local API server running at f.port,
    46  // downgrades the scheme to http and marks the request context for skipped logging.
    47  // API requests are marked for skipping the roundtrip.
    48  func (f *Forwarder) ModifyRequest(req *http.Request) error {
    49  	ctx := martian.NewContext(req)
    50  	ctx.APIRequest()
    51  	ctx.SkipLogging()
    52  
    53  	in := req.URL.String()
    54  	req.URL.Scheme = "http"
    55  	req.URL.Host = fmt.Sprintf("%s:%d", f.host, f.port)
    56  	out := req.URL.String()
    57  	log.Infof("api.Forwarder: forwarding %s to %s", in, out)
    58  
    59  	return nil
    60  }