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package handlers
import (
"bytes"
"context"
"errors"
"io"
"io/ioutil"
"log"
"net/http"
"net/url"
"path"
"strconv"
"github.com/coreos/discovery.etcd.io/handlers/httperror"
"github.com/prometheus/client_golang/prometheus"
)
func init() {
tokenCounter = prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "endpoint_token_requests_total",
Help: "How many /token requests processed, partitioned by status code and HTTP method.",
},
[]string{"code", "method"},
)
prometheus.MustRegister(tokenCounter)
}
var tokenCounter *prometheus.CounterVec
func (st *State) proxyRequest(r *http.Request) (*http.Response, error) {
body, _ := ioutil.ReadAll(r.Body)
for i := 0; i <= 10; i++ {
u := url.URL{
Scheme: "http",
Host: st.getCurrentLeader(),
Path: path.Join("v2", "keys", "_etcd", "registry", r.URL.Path),
RawQuery: r.URL.RawQuery,
}
buf := bytes.NewBuffer(body)
outreq, err := http.NewRequest(r.Method, u.String(), buf)
if err != nil {
return nil, err
}
copyHeader(outreq.Header, r.Header)
client := http.Client{}
resp, err := client.Do(outreq)
if err != nil {
return nil, err
}
// Try again on the next host
if resp.StatusCode == 307 &&
(r.Method == "PUT" || r.Method == "DELETE") {
u, err := resp.Location()
if err != nil {
return nil, err
}
st.setCurrentLeader(u.Host)
continue
}
return resp, nil
}
return nil, errors.New("All attempts at proxying to etcd failed")
}
// copyHeader copies all of the headers from dst to src.
func copyHeader(dst, src http.Header) {
for k, v := range src {
for _, q := range v {
dst.Add(k, q)
}
}
}
func TokenHandler(ctx context.Context, w http.ResponseWriter, r *http.Request) {
st := ctx.Value(stateKey).(*State)
resp, err := st.proxyRequest(r)
if err != nil {
log.Printf("Error making request: %v", err)
httperror.Error(w, r, "", 500, tokenCounter)
}
copyHeader(w.Header(), resp.Header)
w.WriteHeader(resp.StatusCode)
io.Copy(w, resp.Body)
tokenCounter.WithLabelValues(strconv.Itoa(resp.StatusCode), r.Method).Add(1)
}
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