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tyk_reverse_proxy_clone.go
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tyk_reverse_proxy_clone.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// HTTP reverse proxy handler
package main
import (
"bytes"
"crypto/tls"
"github.com/TykTechnologies/logrus"
"github.com/gorilla/context"
"github.com/pmylund/go-cache"
"io"
"io/ioutil"
"net"
"net/http"
"net/url"
"strconv"
"strings"
"sync"
"time"
"github.com/TykTechnologies/tykcommon"
)
var ServiceCache *cache.Cache
func GetURLFromService(spec *APISpec) (*tykcommon.HostList, error) {
doCacheRefresh := func () (*tykcommon.HostList, error) {
log.Debug("--> Refreshing")
spec.ServiceRefreshInProgress = true
sd := ServiceDiscovery{}
sd.New(&spec.Proxy.ServiceDiscovery)
data, err := sd.GetTarget(spec.Proxy.ServiceDiscovery.QueryEndpoint)
if err == nil {
// Set the cached value
if data.Len() == 0 {
spec.HasRun = true
spec.ServiceRefreshInProgress = false
log.Warning("[PROXY][SD] Service Discovery returned empty host list! Returning last good set.")
return spec.LastGoodHostList, nil
}
ServiceCache.Set(spec.APIID, data, cache.DefaultExpiration)
// Stash it too
spec.LastGoodHostList = data
spec.HasRun = true
spec.ServiceRefreshInProgress = false
return data, err
}
spec.ServiceRefreshInProgress = false
return nil, err
}
// First time? Refresh the cache and return that
if !spec.HasRun {
log.Debug("First run! Setting cache")
return doCacheRefresh()
}
// Not first run - check the cache
cachedServiceData, found := ServiceCache.Get(spec.APIID)
if !found {
if spec.ServiceRefreshInProgress {
// Are we already refreshing the cache? skip and return last good conf
log.Debug("Cache expired! But service refresh in progress")
return spec.LastGoodHostList, nil
} else {
// Refresh the spec
log.Debug("Cache expired! Refreshing...")
return doCacheRefresh()
}
}
log.Debug("Returning from cache.")
return cachedServiceData.(*tykcommon.HostList), nil
}
func EnsureTransport(host string) string {
if strings.HasPrefix(host, "https://") {
return host
}
if strings.HasPrefix(host, "http://") {
return host
}
// no prototcol, assum ehttp
host = "http://" + host
return host
}
func GetNextTarget(targetData *tykcommon.HostList, spec *APISpec) string {
if spec.Proxy.EnableLoadBalancing {
log.Debug("[PROXY] [LOAD BALANCING] Load balancer enabled, getting upstream target")
// Use a HostList
spec.RoundRobin.Lock()
spec.RoundRobin.SetMax(targetData)
startPos := spec.RoundRobin.GetPos()
spec.RoundRobin.Unlock()
pos := startPos
for {
gotHost, err := targetData.GetIndex(pos)
if err != nil {
log.Error("[PROXY] [LOAD BALANCING] ", err)
return gotHost
}
host := EnsureTransport(gotHost)
if !spec.Proxy.CheckHostAgainstUptimeTests {
return host // we don't care if it's up
}
if !GlobalHostChecker.IsHostDown(host) {
return host // we do care and it's up
}
// if the host is down, keep trying all the rest
// in order from where we started.
if pos = (pos + 1) % targetData.Len(); pos == startPos {
log.Error("[PROXY] [LOAD BALANCING] All hosts seem to be down, all uptime tests are failing!")
return host
}
}
}
// Use standard target - might still be service data
log.Debug("TARGET DATA:", targetData)
gotHost, err := targetData.GetIndex(0)
if err != nil {
log.Error("[PROXY] ", err)
return gotHost
}
return EnsureTransport(gotHost)
}
// TykNewSingleHostReverseProxy returns a new ReverseProxy that rewrites
// URLs to the scheme, host, and base path provided in target. If the
// target's path is "/base" and the incoming request was for "/dir",
// the target request will be for /base/dir. This version modifies the
// stdlib version by also setting the host to the target, this allows
// us to work with heroku and other such providers
func TykNewSingleHostReverseProxy(target *url.URL, spec *APISpec) *ReverseProxy {
// initalise round robin
spec.RoundRobin = &RoundRobin{}
spec.RoundRobin.SetMax(tykcommon.NewHostList())
if spec.Proxy.ServiceDiscovery.UseDiscoveryService {
log.Debug("[PROXY] Service discovery enabled")
if ServiceCache == nil {
log.Debug("[PROXY] Service cache initialising")
expiry := 120
if config.ServiceDiscovery.DefaultCacheTimeout > 0 {
expiry = config.ServiceDiscovery.DefaultCacheTimeout
}
ServiceCache = cache.New(time.Duration(expiry)*time.Second, 15*time.Second)
}
}
targetQuery := target.RawQuery
director := func(req *http.Request) {
var targetSet bool
if spec.Proxy.ServiceDiscovery.UseDiscoveryService {
tempTargetURL, tErr := GetURLFromService(spec)
if tErr != nil {
log.Error("[PROXY] [SERVICE DISCOVERY] Failed target lookup: ", tErr)
} else {
// No error, replace the target
if spec.Proxy.EnableLoadBalancing {
remote, err := url.Parse(GetNextTarget(tempTargetURL, spec))
if err != nil {
log.Error("[PROXY] [SERVICE DISCOVERY] Couldn't parse target URL:", err)
} else {
// Only replace target if everything is OK
target = remote
targetQuery = target.RawQuery
}
} else {
remote, err := url.Parse(GetNextTarget(tempTargetURL, spec))
if err != nil {
log.Error("[PROXY] [SERVICE DISCOVERY] Couldn't parse target URL:", err)
} else {
// Only replace target if everything is OK
target = remote
targetQuery = target.RawQuery
}
}
}
// We've overriden remote now, don;t need to do it again
targetSet = true
}
if !targetSet {
// no override, better check if LB is enabled
if spec.Proxy.EnableLoadBalancing {
// it is, lets get that target data
lbRemote, lbErr := url.Parse(GetNextTarget(spec.Proxy.StructuredTargetList, spec))
if lbErr != nil {
log.Error("[PROXY] [LOAD BALANCING] Couldn't parse target URL:", lbErr)
} else {
// Only replace target if everything is OK
target = lbRemote
targetQuery = target.RawQuery
}
}
}
// Specifically override with a URL rewrite
var newTarget *url.URL
switchTargets := false
if spec.URLRewriteEnabled {
URLRewriteContainsTarget, found := context.GetOk(req, RetainHost)
if found {
if URLRewriteContainsTarget.(bool) {
log.Debug("Detected host rewrite, overriding target")
tmpTarget, pErr := url.Parse(req.URL.String())
if pErr != nil {
log.Error("Failed to parse URL! Err: ", pErr)
} else {
newTarget = tmpTarget
switchTargets = true
}
context.Clear(req)
}
}
}
// No override, and no load balancing? Use the existing target
var targetToUse *url.URL = target
if switchTargets {
targetToUse = newTarget
}
if targetToUse == target {
req.URL.Scheme = targetToUse.Scheme
req.URL.Host = targetToUse.Host
req.URL.Path = singleJoiningSlash(targetToUse.Path, req.URL.Path)
}
if !spec.Proxy.PreserveHostHeader {
req.Host = targetToUse.Host
}
if targetQuery == "" || req.URL.RawQuery == "" {
req.URL.RawQuery = targetQuery + req.URL.RawQuery
} else {
req.URL.RawQuery = targetQuery + "&" + req.URL.RawQuery
}
}
return &ReverseProxy{Director: director, TykAPISpec: spec, FlushInterval: time.Duration(config.HttpServerOptions.FlushInterval) * time.Millisecond}
}
// onExitFlushLoop is a callback set by tests to detect the state of the
// flushLoop() goroutine.
var onExitFlushLoop func()
// ReverseProxy is an HTTP Handler that takes an incoming request and
// sends it to another server, proxying the response back to the
// client.
type ReverseProxy struct {
// Director must be a function which modifies
// the request into a new request to be sent
// using Transport. Its response is then copied
// back to the original client unmodified.
Director func(*http.Request)
// The transport used to perform proxy requests.
// If nil, http.DefaultTransport is used.
Transport http.RoundTripper
// FlushInterval specifies the flush interval
// to flush to the client while copying the
// response body.
// If zero, no periodic flushing is done.
FlushInterval time.Duration
// TLSClientConfig specifies the TLS configuration to use for 'wss'.
// If nil, the default configuration is used.
TLSClientConfig *tls.Config
TykAPISpec *APISpec
ErrorHandler ErrorHandler
ResponseHandler ResponseChain
}
type TykTransporter struct {
http.Transport
}
func (t *TykTransporter) SetDialFunc(Dial func(string, string) (net.Conn, error)) {
t.Dial = Dial
}
func (t *TykTransporter) SetTimeout(timeOut int) {
//t.Dial.Timeout = time.Duration(timeOut) * time.Second
t.ResponseHeaderTimeout = time.Duration(timeOut) * time.Second
}
func getMaxIdleConns() int {
return config.MaxIdleConnsPerHost
}
var TykDefaultTransport *TykTransporter = &TykTransporter{http.Transport{
Proxy: http.ProxyFromEnvironment,
MaxIdleConnsPerHost: getMaxIdleConns(),
Dial: (&net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
}).Dial,
TLSHandshakeTimeout: 10 * time.Second,
TLSClientConfig: &tls.Config{},
}}
func cleanSlashes(a string) string {
endSlash := strings.HasSuffix(a, "//")
startSlash := strings.HasPrefix(a, "//")
if startSlash {
a = "/" + strings.TrimPrefix(a, "//")
}
if endSlash {
a = strings.TrimSuffix(a, "//") + "/"
}
return a
}
func singleJoiningSlash(a, b string) string {
a = cleanSlashes(a)
b = cleanSlashes(b)
aslash := strings.HasSuffix(a, "/")
bslash := strings.HasPrefix(b, "/")
switch {
case aslash && bslash:
log.Debug(a + b)
return a + b[1:]
case !aslash && !bslash:
if len(b) > 0 {
log.Debug(a + b)
return a + "/" + b
} else {
log.Debug(a + b)
return a
}
}
log.Debug(a + b)
return a + b
}
func copyHeader(dst, src http.Header) {
for k, vv := range src {
for _, v := range vv {
dst.Add(k, v)
}
}
}
// Hop-by-hop headers. These are removed when sent to the backend.
// http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html
var hopHeaders = []string{
"Connection",
"Keep-Alive",
"Proxy-Authenticate",
"Proxy-Authorization",
"Te", // canonicalized version of "TE"
"Trailers",
"Transfer-Encoding",
"Upgrade",
}
func (p *ReverseProxy) ReturnRequestServeHttp(rw http.ResponseWriter, req *http.Request) *http.Request {
outreq := new(http.Request)
p.ServeHTTP(rw, req)
return outreq
}
func (p *ReverseProxy) New(c interface{}, spec *APISpec) (TykResponseHandler, error) {
p.ErrorHandler = ErrorHandler{TykMiddleware: &TykMiddleware{spec, p}}
return nil, nil
}
func (p *ReverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) *http.Response {
return p.WrappedServeHTTP(rw, req, RecordDetail(req))
// return nil
}
func (p *ReverseProxy) ServeHTTPForCache(rw http.ResponseWriter, req *http.Request) *http.Response {
return p.WrappedServeHTTP(rw, req, true)
}
func (p *ReverseProxy) CheckHardTimeoutEnforced(spec *APISpec, req *http.Request) (bool, int) {
if !spec.EnforcedTimeoutEnabled {
return false, config.ProxyDefaultTimeout
}
var stat RequestStatus
var meta interface{}
var found bool
_, versionPaths, _, _ := spec.GetVersionData(req)
found, meta = spec.CheckSpecMatchesStatus(req.URL.Path, req.Method, versionPaths, HardTimeout)
if found {
stat = StatusHardTimeout
}
if stat == StatusHardTimeout {
thisMeta := meta.(*int)
log.Debug("HARD TIMEOUT ENFORCED: ", *thisMeta)
return true, *thisMeta
}
return false, config.ProxyDefaultTimeout
}
func (p *ReverseProxy) CheckCircuitBreakerEnforced(spec *APISpec, req *http.Request) (bool, *ExtendedCircuitBreakerMeta) {
if !spec.CircuitBreakerEnabled {
return false, nil
}
var stat RequestStatus
var meta interface{}
var found bool
_, versionPaths, _, _ := spec.GetVersionData(req)
found, meta = spec.CheckSpecMatchesStatus(req.URL.Path, req.Method, versionPaths, CircuitBreaker)
if found {
stat = StatusCircuitBreaker
}
if stat == StatusCircuitBreaker {
thisMeta := meta.(*ExtendedCircuitBreakerMeta)
log.Debug("CB Enforced for path: ", *thisMeta)
return true, thisMeta
}
return false, nil
}
func GetTransport(timeOut int, rw http.ResponseWriter, req *http.Request, p *ReverseProxy) http.RoundTripper {
var thisTransport *TykTransporter = TykDefaultTransport
thisTransport.TLSClientConfig.InsecureSkipVerify = config.ProxySSLInsecureSkipVerify
// Use the default unless we've modified the timout
if timeOut > 0 {
log.Debug("Setting timeout for outbound request to: ", timeOut)
thisTransport.SetDialFunc((&net.Dialer{
Timeout: time.Duration(timeOut) * time.Second,
KeepAlive: 30 * time.Second,
}).Dial)
thisTransport.SetTimeout(timeOut)
}
if IsWebsocket(req) {
wsTransport := &WSDialer{thisTransport, rw, p.TLSClientConfig}
return wsTransport
}
return thisTransport
}
func (p *ReverseProxy) WrappedServeHTTP(rw http.ResponseWriter, req *http.Request, withCache bool) *http.Response {
transport := p.Transport
// 1. Check if timeouts are set for this endpoint
_, timeout := p.CheckHardTimeoutEnforced(p.TykAPISpec, req)
transport = GetTransport(timeout, rw, req, p)
// Do this before we make a shallow copy
sessVal := context.Get(req, SessionData)
outreq := new(http.Request)
logreq := new(http.Request)
log.Debug("UPSTREAM REQUEST URL: ", req.URL)
// We need to double set the context for the outbound request to reprocess the target
if p.TykAPISpec.URLRewriteEnabled {
URLRewriteContainsTarget, found := context.GetOk(req, RetainHost)
if found {
if URLRewriteContainsTarget.(bool) {
log.Debug("Detected host rewrite, notifying director")
context.Set(outreq, RetainHost, true)
}
}
}
*outreq = *req // includes shallow copies of maps, but okay
*logreq = *req
p.Director(outreq)
outreq.Proto = "HTTP/1.1"
outreq.ProtoMajor = 1
outreq.ProtoMinor = 1
outreq.Close = false
log.Debug("Outbound Request: ", outreq.URL.String())
// Do not modify outbound request headers if they are WS
if !IsWebsocket(outreq) {
// Remove hop-by-hop headers to the backend. Especially
// important is "Connection" because we want a persistent
// connection, regardless of what the client sent to us. This
// is modifying the same underlying map from req (shallow
// copied above) so we only copy it if necessary.
copiedHeaders := false
for _, h := range hopHeaders {
if outreq.Header.Get(h) != "" {
if !copiedHeaders {
outreq.Header = make(http.Header)
logreq.Header = make(http.Header)
copyHeader(outreq.Header, req.Header)
copyHeader(logreq.Header, req.Header)
copiedHeaders = true
}
outreq.Header.Del(h)
logreq.Header.Del(h)
}
}
}
var thisIP string
if clientIP, _, err := net.SplitHostPort(req.RemoteAddr); err == nil {
// If we aren't the first proxy retain prior
// X-Forwarded-For information as a comma+space
// separated list and fold multiple headers into one.
if prior, ok := outreq.Header["X-Forwarded-For"]; ok {
clientIP = strings.Join(prior, ", ") + ", " + clientIP
}
outreq.Header.Set("X-Forwarded-For", clientIP)
thisIP = clientIP
}
// Circuit breaker
breakerEnforced, breakerConf := p.CheckCircuitBreakerEnforced(p.TykAPISpec, req)
var res *http.Response
var err error
if breakerEnforced {
log.Debug("ON REQUEST: Breaker status: ", breakerConf.CB.Ready())
if breakerConf.CB.Ready() {
res, err = transport.RoundTrip(outreq)
if err != nil {
breakerConf.CB.Fail()
} else if res.StatusCode == 500 {
breakerConf.CB.Fail()
} else {
breakerConf.CB.Success()
}
} else {
p.ErrorHandler.HandleError(rw, logreq, "Service temporarily unnavailable.", 503)
return nil
}
} else {
res, err = transport.RoundTrip(outreq)
}
if err != nil {
var authHeaderValue string
contextAuthVal, authOk := context.GetOk(req, AuthHeaderValue)
if authOk {
authHeaderValue = contextAuthVal.(string)
}
var obfuscated string
if len(authHeaderValue) > 4 {
obfuscated = "****" + authHeaderValue[len(authHeaderValue)-4:]
}
var alias string
if sessVal != nil {
alias = sessVal.(SessionState).Alias
}
log.WithFields(logrus.Fields{
"prefix": "proxy",
"user_ip": thisIP,
"server_name": outreq.Host,
"user_id": obfuscated,
"user_name": alias,
"org_id": p.TykAPISpec.APIDefinition.OrgID,
"api_id": p.TykAPISpec.APIDefinition.APIID,
}).Error("http: proxy error: ", err)
if strings.Contains(err.Error(), "timeout awaiting response headers") {
p.ErrorHandler.HandleError(rw, logreq, "Upstream service reached hard timeout.", 408)
if p.TykAPISpec.Proxy.ServiceDiscovery.UseDiscoveryService {
if ServiceCache != nil {
log.Debug("[PROXY] [SERVICE DISCOVERY] Upstream host failed, refreshing host list")
ServiceCache.Delete(p.TykAPISpec.APIID)
}
}
return nil
}
if strings.Contains(err.Error(), "no such host") {
p.ErrorHandler.HandleError(rw, logreq, "Upstream host lookup failed", 500)
return nil
}
p.ErrorHandler.HandleError(rw, logreq, "There was a problem proxying the request", 500)
return nil
}
if IsWebsocket(req) {
return nil
}
inres := new(http.Response)
if withCache {
*inres = *res // includes shallow copies of maps, but okay
defer res.Body.Close()
// Buffer body data
var bodyBuffer bytes.Buffer
bodyBuffer2 := new(bytes.Buffer)
p.CopyResponse(&bodyBuffer, res.Body)
*bodyBuffer2 = bodyBuffer
// Create new ReadClosers so we can split output
res.Body = ioutil.NopCloser(&bodyBuffer)
inres.Body = ioutil.NopCloser(bodyBuffer2)
}
ses := SessionState{}
if sessVal != nil {
ses = sessVal.(SessionState)
}
if p.TykAPISpec.ResponseHandlersActive {
// Middleware chain handling here - very simple, but should do the trick
chainErr := p.ResponseHandler.Go(p.TykAPISpec.ResponseChain, rw, res, req, &ses)
if chainErr != nil {
log.Error("Response chain failed! ", chainErr)
}
}
// We should at least copy the status code in
inres.StatusCode = res.StatusCode
inres.ContentLength = res.ContentLength
p.HandleResponse(rw, res, req, &ses)
return inres
}
func (p *ReverseProxy) HandleResponse(rw http.ResponseWriter, res *http.Response, req *http.Request, ses *SessionState) error {
for _, h := range hopHeaders {
res.Header.Del(h)
}
defer res.Body.Close()
// Close connections
if config.CloseConnections {
res.Header.Set("Connection", "close")
}
// Add resource headers
if ses != nil {
// We have found a session, lets report back
res.Header.Add("X-RateLimit-Limit", strconv.Itoa(int(ses.QuotaMax)))
res.Header.Add("X-RateLimit-Remaining", strconv.Itoa(int(ses.QuotaRemaining)))
res.Header.Add("X-RateLimit-Reset", strconv.Itoa(int(ses.QuotaRenews)))
}
copyHeader(rw.Header(), res.Header)
rw.WriteHeader(res.StatusCode)
p.CopyResponse(rw, res.Body)
return nil
}
func (p *ReverseProxy) CopyResponse(dst io.Writer, src io.Reader) {
if p.FlushInterval != 0 {
if wf, ok := dst.(writeFlusher); ok {
mlw := &maxLatencyWriter{
dst: wf,
latency: p.FlushInterval,
done: make(chan bool),
}
go mlw.flushLoop()
defer mlw.stop()
dst = mlw
}
}
io.Copy(dst, src)
}
type writeFlusher interface {
io.Writer
http.Flusher
}
type maxLatencyWriter struct {
dst writeFlusher
latency time.Duration
lk sync.Mutex // protects Write + Flush
done chan bool
}
func (m *maxLatencyWriter) Write(p []byte) (int, error) {
m.lk.Lock()
defer m.lk.Unlock()
return m.dst.Write(p)
}
func (m *maxLatencyWriter) flushLoop() {
t := time.NewTicker(m.latency)
defer t.Stop()
for {
select {
case <-m.done:
if onExitFlushLoop != nil {
onExitFlushLoop()
}
return
case <-t.C:
m.lk.Lock()
m.dst.Flush()
m.lk.Unlock()
}
}
}
func (m *maxLatencyWriter) stop() { m.done <- true }