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added ability to register custom log formatter (#131)
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* added ability to register custom log formatter

* changed function type declaration to work on older versions of Go

* changed to an args struct per PR, refactored logging tests to make it easier to see the scenarios

* fixed formatting and linting issues

* split logging into its own file

* removed writer from the LogFormatterParams struct

* split all logging tests into a separate file

* fixed formatting
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@mlsquires @kisielk
mlsquires authored and kisielk committed Jul 27, 2018
1 parent 6257a58 commit 7e0847f
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Showing 4 changed files with 563 additions and 455 deletions.
225 changes: 0 additions & 225 deletions handlers.go
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Expand Up @@ -7,15 +7,10 @@ package handlers
import (
"bufio"
"fmt"
"io"
"net"
"net/http"
"net/url"
"sort"
"strconv"
"strings"
"time"
"unicode/utf8"
)

// MethodHandler is an http.Handler that dispatches to a handler whose key in the
Expand Down Expand Up @@ -48,59 +43,6 @@ func (h MethodHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
}
}

// loggingHandler is the http.Handler implementation for LoggingHandlerTo and its
// friends
type loggingHandler struct {
writer io.Writer
handler http.Handler
}

// combinedLoggingHandler is the http.Handler implementation for LoggingHandlerTo
// and its friends
type combinedLoggingHandler struct {
writer io.Writer
handler http.Handler
}

func (h loggingHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
t := time.Now()
logger := makeLogger(w)
url := *req.URL
h.handler.ServeHTTP(logger, req)
writeLog(h.writer, req, url, t, logger.Status(), logger.Size())
}

func (h combinedLoggingHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
t := time.Now()
logger := makeLogger(w)
url := *req.URL
h.handler.ServeHTTP(logger, req)
writeCombinedLog(h.writer, req, url, t, logger.Status(), logger.Size())
}

func makeLogger(w http.ResponseWriter) loggingResponseWriter {
var logger loggingResponseWriter = &responseLogger{w: w, status: http.StatusOK}
if _, ok := w.(http.Hijacker); ok {
logger = &hijackLogger{responseLogger{w: w, status: http.StatusOK}}
}
h, ok1 := logger.(http.Hijacker)
c, ok2 := w.(http.CloseNotifier)
if ok1 && ok2 {
return hijackCloseNotifier{logger, h, c}
}
if ok2 {
return &closeNotifyWriter{logger, c}
}
return logger
}

type commonLoggingResponseWriter interface {
http.ResponseWriter
http.Flusher
Status() int
Size() int
}

// responseLogger is wrapper of http.ResponseWriter that keeps track of its HTTP
// status code and body size
type responseLogger struct {
Expand Down Expand Up @@ -165,173 +107,6 @@ type hijackCloseNotifier struct {
http.CloseNotifier
}

const lowerhex = "0123456789abcdef"

func appendQuoted(buf []byte, s string) []byte {
var runeTmp [utf8.UTFMax]byte
for width := 0; len(s) > 0; s = s[width:] {
r := rune(s[0])
width = 1
if r >= utf8.RuneSelf {
r, width = utf8.DecodeRuneInString(s)
}
if width == 1 && r == utf8.RuneError {
buf = append(buf, `\x`...)
buf = append(buf, lowerhex[s[0]>>4])
buf = append(buf, lowerhex[s[0]&0xF])
continue
}
if r == rune('"') || r == '\\' { // always backslashed
buf = append(buf, '\\')
buf = append(buf, byte(r))
continue
}
if strconv.IsPrint(r) {
n := utf8.EncodeRune(runeTmp[:], r)
buf = append(buf, runeTmp[:n]...)
continue
}
switch r {
case '\a':
buf = append(buf, `\a`...)
case '\b':
buf = append(buf, `\b`...)
case '\f':
buf = append(buf, `\f`...)
case '\n':
buf = append(buf, `\n`...)
case '\r':
buf = append(buf, `\r`...)
case '\t':
buf = append(buf, `\t`...)
case '\v':
buf = append(buf, `\v`...)
default:
switch {
case r < ' ':
buf = append(buf, `\x`...)
buf = append(buf, lowerhex[s[0]>>4])
buf = append(buf, lowerhex[s[0]&0xF])
case r > utf8.MaxRune:
r = 0xFFFD
fallthrough
case r < 0x10000:
buf = append(buf, `\u`...)
for s := 12; s >= 0; s -= 4 {
buf = append(buf, lowerhex[r>>uint(s)&0xF])
}
default:
buf = append(buf, `\U`...)
for s := 28; s >= 0; s -= 4 {
buf = append(buf, lowerhex[r>>uint(s)&0xF])
}
}
}
}
return buf

}

// buildCommonLogLine builds a log entry for req in Apache Common Log Format.
// ts is the timestamp with which the entry should be logged.
// status and size are used to provide the response HTTP status and size.
func buildCommonLogLine(req *http.Request, url url.URL, ts time.Time, status int, size int) []byte {
username := "-"
if url.User != nil {
if name := url.User.Username(); name != "" {
username = name
}
}

host, _, err := net.SplitHostPort(req.RemoteAddr)

if err != nil {
host = req.RemoteAddr
}

uri := req.RequestURI

// Requests using the CONNECT method over HTTP/2.0 must use
// the authority field (aka r.Host) to identify the target.
// Refer: https://httpwg.github.io/specs/rfc7540.html#CONNECT
if req.ProtoMajor == 2 && req.Method == "CONNECT" {
uri = req.Host
}
if uri == "" {
uri = url.RequestURI()
}

buf := make([]byte, 0, 3*(len(host)+len(username)+len(req.Method)+len(uri)+len(req.Proto)+50)/2)
buf = append(buf, host...)
buf = append(buf, " - "...)
buf = append(buf, username...)
buf = append(buf, " ["...)
buf = append(buf, ts.Format("02/Jan/2006:15:04:05 -0700")...)
buf = append(buf, `] "`...)
buf = append(buf, req.Method...)
buf = append(buf, " "...)
buf = appendQuoted(buf, uri)
buf = append(buf, " "...)
buf = append(buf, req.Proto...)
buf = append(buf, `" `...)
buf = append(buf, strconv.Itoa(status)...)
buf = append(buf, " "...)
buf = append(buf, strconv.Itoa(size)...)
return buf
}

// writeLog writes a log entry for req to w in Apache Common Log Format.
// ts is the timestamp with which the entry should be logged.
// status and size are used to provide the response HTTP status and size.
func writeLog(w io.Writer, req *http.Request, url url.URL, ts time.Time, status, size int) {
buf := buildCommonLogLine(req, url, ts, status, size)
buf = append(buf, '\n')
w.Write(buf)
}

// writeCombinedLog writes a log entry for req to w in Apache Combined Log Format.
// ts is the timestamp with which the entry should be logged.
// status and size are used to provide the response HTTP status and size.
func writeCombinedLog(w io.Writer, req *http.Request, url url.URL, ts time.Time, status, size int) {
buf := buildCommonLogLine(req, url, ts, status, size)
buf = append(buf, ` "`...)
buf = appendQuoted(buf, req.Referer())
buf = append(buf, `" "`...)
buf = appendQuoted(buf, req.UserAgent())
buf = append(buf, '"', '\n')
w.Write(buf)
}

// CombinedLoggingHandler return a http.Handler that wraps h and logs requests to out in
// Apache Combined Log Format.
//
// See http://httpd.apache.org/docs/2.2/logs.html#combined for a description of this format.
//
// LoggingHandler always sets the ident field of the log to -
func CombinedLoggingHandler(out io.Writer, h http.Handler) http.Handler {
return combinedLoggingHandler{out, h}
}

// LoggingHandler return a http.Handler that wraps h and logs requests to out in
// Apache Common Log Format (CLF).
//
// See http://httpd.apache.org/docs/2.2/logs.html#common for a description of this format.
//
// LoggingHandler always sets the ident field of the log to -
//
// Example:
//
// r := mux.NewRouter()
// r.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
// w.Write([]byte("This is a catch-all route"))
// })
// loggedRouter := handlers.LoggingHandler(os.Stdout, r)
// http.ListenAndServe(":1123", loggedRouter)
//
func LoggingHandler(out io.Writer, h http.Handler) http.Handler {
return loggingHandler{out, h}
}

// isContentType validates the Content-Type header matches the supplied
// contentType. That is, its type and subtype match.
func isContentType(h http.Header, contentType string) bool {
Expand Down

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