sourcegraph/cmd/github-proxy/github-proxy.go at master · IntelDan/sourcegraph · GitHub

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package main

import (

"bytes"

"io"

"io/ioutil"

"log"

"net"

"net/http"

"net/url"

"os"

"os/signal"

"strconv"

"strings"

"sync"

"syscall"

"github.com/gorilla/handlers"

"github.com/prometheus/client_golang/prometheus"

log15 "gopkg.in/inconshreveable/log15.v2"

"github.com/sourcegraph/sourcegraph/pkg/conf"

"github.com/sourcegraph/sourcegraph/pkg/debugserver"

"github.com/sourcegraph/sourcegraph/pkg/env"

"github.com/sourcegraph/sourcegraph/pkg/tracer"

)

var (

logRequests, _ = strconv.ParseBool(env.Get("LOG_REQUESTS", "", "log HTTP requests"))

)

const port = "3180"

// requestMu ensures we only do one request at a time to prevent tripping abuse detection.

var requestMu sync.Mutex

var rateLimitRemainingGauge = prometheus.NewGaugeVec(prometheus.GaugeOpts{

Namespace: "src",

Subsystem: "github",

Name: "rate_limit_remaining",

Help: "Number of calls to GitHub's API remaining before hitting the rate limit.",

}, []string{"resource"})

func init() {

rateLimitRemainingGauge.WithLabelValues("core").Set(5000)

rateLimitRemainingGauge.WithLabelValues("search").Set(30)

prometheus.MustRegister(rateLimitRemainingGauge)

}

// list obtained from httputil of headers not to forward.

var hopHeaders = map[string]struct{}{

"Connection": {},

"Proxy-Connection": {}, // non-standard but still sent by libcurl and rejected by e.g. google

"Keep-Alive": {},

"Proxy-Authenticate": {},

"Proxy-Authorization": {},

"Te": {}, // canonicalized version of "TE"

"Trailer": {}, // not Trailers per URL above; http://www.rfc-editor.org/errata_search.php?eid=4522

"Transfer-Encoding": {},

"Upgrade": {},

}

func main() {

env.Lock()

env.HandleHelpFlag()

tracer.Init()

go func() {

c := make(chan os.Signal, 1)

signal.Notify(c, syscall.SIGINT, syscall.SIGHUP)

<-c

os.Exit(0)

}()

go debugserver.Start()

var (

authenticateRequestMu sync.RWMutex

authenticateRequest func(query url.Values, header http.Header)

)

conf.Watch(func() {

cfg := conf.Get()

if clientID, clientSecret := cfg.GithubClientID, cfg.GithubClientSecret; clientID != "" && clientSecret != "" {

authenticateRequestMu.Lock()

authenticateRequest = func(query url.Values, header http.Header) {

query.Set("client_id", clientID)

query.Set("client_secret", clientSecret)

}

authenticateRequestMu.Unlock()

}

})

var h http.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {

q2 := r.URL.Query()

h2 := make(http.Header)

for k, v := range r.Header {

if _, found := hopHeaders[k]; !found {

h2[k] = v

}

// Authenticate for higher rate limits.

authenticateRequestMu.RLock()

authRequest := authenticateRequest

authenticateRequestMu.RUnlock()

if authRequest != nil {

authRequest(q2, h2)

}

req2 := &http.Request{

Method: r.Method,

Body: r.Body,

URL: &url.URL{

Scheme: "https",

Host: "api.github.com",

Path: r.URL.Path,

RawQuery: q2.Encode(),

Header: h2,

}

requestMu.Lock()

resp, err := http.DefaultClient.Do(req2)

requestMu.Unlock()

if err != nil {

log.Print(err)

http.Error(w, err.Error(), http.StatusInternalServerError)

return

}

defer resp.Body.Close()

if limit := resp.Header.Get("X-Ratelimit-Remaining"); limit != "" {

limit, _ := strconv.Atoi(limit)

resource := "core"

if strings.HasPrefix(r.URL.Path, "/search/") {

resource = "search"

} else if r.URL.Path == "/graphql" {

resource = "graphql"

}

rateLimitRemainingGauge.WithLabelValues(resource).Set(float64(limit))

}

for k, v := range resp.Header {

w.Header()[k] = v

}

w.WriteHeader(resp.StatusCode)

if resp.StatusCode < 400 || !logRequests {

io.Copy(w, resp.Body)

return

}

b, err := ioutil.ReadAll(resp.Body)

log15.Warn("proxy error", "status", resp.StatusCode, "body", string(b), "bodyErr", err)

io.Copy(w, bytes.NewReader(b))

})

if logRequests {

h = handlers.LoggingHandler(os.Stdout, h)

}

h = prometheus.InstrumentHandler("github-proxy", h)

http.Handle("/", h)

host := ""

if env.InsecureDev {

host = "127.0.0.1"

}

addr := net.JoinHostPort(host, port)

log15.Info("github-proxy: listening", "addr", addr)

log.Fatal(http.ListenAndServe(addr, nil))

}

sourcegraph/cmd/github-proxy/github-proxy.go at master · IntelDan/sourcegraph · GitHub

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