oauth2_proxy/logging_handler.go

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// largely adapted from https://github.com/gorilla/handlers/blob/master/handlers.go
// to add logging of request duration as last value (and drop referrer)
package main
import (
"fmt"
"io"
"net"
"net/http"
"net/url"
"time"
)
// responseLogger is wrapper of http.ResponseWriter that keeps track of its HTTP status
// code and body size
type responseLogger struct {
w http.ResponseWriter
status int
size int
upstream string
authInfo string
}
func (l *responseLogger) Header() http.Header {
return l.w.Header()
}
func (l *responseLogger) ExtractGAPMetadata() {
upstream := l.w.Header().Get("GAP-Upstream-Address")
if upstream != "" {
l.upstream = upstream
l.w.Header().Del("GAP-Upstream-Address")
}
authInfo := l.w.Header().Get("GAP-Auth")
if authInfo != "" {
l.authInfo = authInfo
l.w.Header().Del("GAP-Auth")
}
}
func (l *responseLogger) Write(b []byte) (int, error) {
if l.status == 0 {
// The status will be StatusOK if WriteHeader has not been called yet
l.status = http.StatusOK
}
l.ExtractGAPMetadata()
size, err := l.w.Write(b)
l.size += size
return size, err
}
func (l *responseLogger) WriteHeader(s int) {
l.ExtractGAPMetadata()
l.w.WriteHeader(s)
l.status = s
}
func (l *responseLogger) Status() int {
return l.status
}
func (l *responseLogger) Size() int {
return l.size
}
// loggingHandler is the http.Handler implementation for LoggingHandlerTo and its friends
type loggingHandler struct {
writer io.Writer
handler http.Handler
enabled bool
}
func LoggingHandler(out io.Writer, h http.Handler, v bool) http.Handler {
return loggingHandler{out, h, v}
}
func (h loggingHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
t := time.Now()
url := *req.URL
logger := &responseLogger{w: w}
h.handler.ServeHTTP(logger, req)
if !h.enabled {
return
}
logLine := buildLogLine(logger.authInfo, logger.upstream, req, url, t, logger.Status(), logger.Size())
h.writer.Write(logLine)
}
// Log entry for req similar to Apache Common Log Format.
// ts is the timestamp with which the entry should be logged.
// status, size are used to provide the response HTTP status and size.
func buildLogLine(username, upstream string, req *http.Request, url url.URL, ts time.Time, status int, size int) []byte {
if username == "" {
username = "-"
}
if upstream == "" {
upstream = "-"
}
if url.User != nil && username == "-" {
if name := url.User.Username(); name != "" {
username = name
}
}
client := req.Header.Get("X-Real-IP")
if client == "" {
client = req.RemoteAddr
}
if c, _, err := net.SplitHostPort(client); err == nil {
client = c
}
duration := float64(time.Now().Sub(ts)) / float64(time.Second)
logLine := fmt.Sprintf("%s - %s [%s] %s %s %s %q %s %q %d %d %0.3f\n",
client,
username,
ts.Format("02/Jan/2006:15:04:05 -0700"),
req.Host,
req.Method,
upstream,
url.RequestURI(),
req.Proto,
req.UserAgent(),
status,
size,
duration,
)
return []byte(logLine)
}