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proxy: Move handling of headers around to prevent memory usage spikes (#784)
* Move handling of headers around to prevent memory use spikes While debugging #782, I noticed that using http2 and max_fails=0, X-Forwarded-For grew infinitely when an upstream request failed after refreshing the test page. This change ensures that headers are only set once per request rather than appending in a time-terminated loop. * Refactor some code into its own function
This commit is contained in:
Matt Holt
parent
f561dc0bc1
commit
81e26970a3
2 changed files with 95 additions and 95 deletions
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@ -3,8 +3,10 @@ package proxy
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import (
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"errors"
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"net"
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"net/http"
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"net/url"
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"strings"
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"sync/atomic"
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"time"
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@ -75,71 +77,108 @@ var tryDuration = 60 * time.Second
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// ServeHTTP satisfies the middleware.Handler interface.
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func (p Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
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for _, upstream := range p.Upstreams {
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if middleware.Path(r.URL.Path).Matches(upstream.From()) && upstream.AllowedPath(r.URL.Path) {
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var replacer middleware.Replacer
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start := time.Now()
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requestHost := r.Host
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if !middleware.Path(r.URL.Path).Matches(upstream.From()) ||
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!upstream.AllowedPath(r.URL.Path) {
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continue
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}
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// Since Select() should give us "up" hosts, keep retrying
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// hosts until timeout (or until we get a nil host).
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for time.Now().Sub(start) < tryDuration {
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host := upstream.Select()
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if host == nil {
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return http.StatusBadGateway, errUnreachable
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}
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proxy := host.ReverseProxy
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r.Host = host.Name
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if rr, ok := w.(*middleware.ResponseRecorder); ok && rr.Replacer != nil {
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rr.Replacer.Set("upstream", host.Name)
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}
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var replacer middleware.Replacer
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start := time.Now()
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if baseURL, err := url.Parse(host.Name); err == nil {
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r.Host = baseURL.Host
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if proxy == nil {
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proxy = NewSingleHostReverseProxy(baseURL, host.WithoutPathPrefix)
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}
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} else if proxy == nil {
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return http.StatusInternalServerError, err
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outreq := createUpstreamRequest(r)
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// Since Select() should give us "up" hosts, keep retrying
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// hosts until timeout (or until we get a nil host).
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for time.Now().Sub(start) < tryDuration {
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host := upstream.Select()
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if host == nil {
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return http.StatusBadGateway, errUnreachable
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}
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if rr, ok := w.(*middleware.ResponseRecorder); ok && rr.Replacer != nil {
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rr.Replacer.Set("upstream", host.Name)
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}
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outreq.Host = host.Name
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if host.ExtraHeaders != nil {
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extraHeaders := make(http.Header)
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if replacer == nil {
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rHost := r.Host
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replacer = middleware.NewReplacer(r, nil, "")
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outreq.Host = rHost
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}
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var extraHeaders http.Header
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if host.ExtraHeaders != nil {
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extraHeaders = make(http.Header)
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if replacer == nil {
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rHost := r.Host
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r.Host = requestHost
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replacer = middleware.NewReplacer(r, nil, "")
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r.Host = rHost
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}
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for header, values := range host.ExtraHeaders {
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for _, value := range values {
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extraHeaders.Add(header,
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replacer.Replace(value))
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if header == "Host" {
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r.Host = replacer.Replace(value)
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}
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for header, values := range host.ExtraHeaders {
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for _, value := range values {
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extraHeaders.Add(header, replacer.Replace(value))
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if header == "Host" {
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outreq.Host = replacer.Replace(value)
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}
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}
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}
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atomic.AddInt64(&host.Conns, 1)
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backendErr := proxy.ServeHTTP(w, r, extraHeaders)
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atomic.AddInt64(&host.Conns, -1)
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if backendErr == nil {
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return 0, nil
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for k, v := range extraHeaders {
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outreq.Header[k] = v
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}
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timeout := host.FailTimeout
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if timeout == 0 {
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timeout = 10 * time.Second
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}
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atomic.AddInt32(&host.Fails, 1)
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go func(host *UpstreamHost, timeout time.Duration) {
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time.Sleep(timeout)
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atomic.AddInt32(&host.Fails, -1)
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}(host, timeout)
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}
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return http.StatusBadGateway, errUnreachable
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proxy := host.ReverseProxy
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if baseURL, err := url.Parse(host.Name); err == nil {
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r.Host = baseURL.Host
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if proxy == nil {
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proxy = NewSingleHostReverseProxy(baseURL, host.WithoutPathPrefix)
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}
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} else if proxy == nil {
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return http.StatusInternalServerError, err
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}
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atomic.AddInt64(&host.Conns, 1)
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backendErr := proxy.ServeHTTP(w, outreq)
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atomic.AddInt64(&host.Conns, -1)
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if backendErr == nil {
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return 0, nil
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}
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timeout := host.FailTimeout
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if timeout == 0 {
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timeout = 10 * time.Second
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}
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atomic.AddInt32(&host.Fails, 1)
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go func(host *UpstreamHost, timeout time.Duration) {
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time.Sleep(timeout)
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atomic.AddInt32(&host.Fails, -1)
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}(host, timeout)
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}
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return http.StatusBadGateway, errUnreachable
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}
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return p.Next.ServeHTTP(w, r)
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}
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// createUpstremRequest shallow-copies r into a new request
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// that can be sent upstream.
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func createUpstreamRequest(r *http.Request) *http.Request {
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outreq := new(http.Request)
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*outreq = *r // includes shallow copies of maps, but okay
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// Remove hop-by-hop headers to the backend. Especially
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// important is "Connection" because we want a persistent
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// connection, regardless of what the client sent to us. This
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// is modifying the same underlying map from r (shallow
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// copied above) so we only copy it if necessary.
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for _, h := range hopHeaders {
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if outreq.Header.Get(h) != "" {
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outreq.Header = make(http.Header)
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copyHeader(outreq.Header, r.Header)
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outreq.Header.Del(h)
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}
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}
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if clientIP, _, err := net.SplitHostPort(r.RemoteAddr); err == nil {
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// If we aren't the first proxy, retain prior
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// X-Forwarded-For information as a comma+space
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// separated list and fold multiple headers into one.
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if prior, ok := outreq.Header["X-Forwarded-For"]; ok {
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clientIP = strings.Join(prior, ", ") + ", " + clientIP
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}
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outreq.Header.Set("X-Forwarded-For", clientIP)
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}
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return outreq
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}
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@ -154,54 +154,18 @@ var InsecureTransport http.RoundTripper = &http.Transport{
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TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
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}
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func (p *ReverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request, extraHeaders http.Header) error {
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func (p *ReverseProxy) ServeHTTP(rw http.ResponseWriter, outreq *http.Request) error {
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transport := p.Transport
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if transport == nil {
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transport = http.DefaultTransport
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}
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outreq := new(http.Request)
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*outreq = *req // includes shallow copies of maps, but okay
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p.Director(outreq)
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outreq.Proto = "HTTP/1.1"
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outreq.ProtoMajor = 1
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outreq.ProtoMinor = 1
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outreq.Close = false
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// Remove hop-by-hop headers to the backend. Especially
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// important is "Connection" because we want a persistent
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// connection, regardless of what the client sent to us. This
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// is modifying the same underlying map from req (shallow
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// copied above) so we only copy it if necessary.
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copiedHeaders := false
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for _, h := range hopHeaders {
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if outreq.Header.Get(h) != "" {
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if !copiedHeaders {
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outreq.Header = make(http.Header)
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copyHeader(outreq.Header, req.Header)
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copiedHeaders = true
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}
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outreq.Header.Del(h)
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}
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}
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if clientIP, _, err := net.SplitHostPort(req.RemoteAddr); err == nil {
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// If we aren't the first proxy retain prior
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// X-Forwarded-For information as a comma+space
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// separated list and fold multiple headers into one.
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if prior, ok := outreq.Header["X-Forwarded-For"]; ok {
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clientIP = strings.Join(prior, ", ") + ", " + clientIP
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}
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outreq.Header.Set("X-Forwarded-For", clientIP)
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}
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if extraHeaders != nil {
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for k, v := range extraHeaders {
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outreq.Header[k] = v
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}
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}
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res, err := transport.RoundTrip(outreq)
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if err != nil {
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return err
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@ -237,9 +201,7 @@ func (p *ReverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request, extr
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for _, h := range hopHeaders {
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res.Header.Del(h)
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}
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copyHeader(rw.Header(), res.Header)
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rw.WriteHeader(res.StatusCode)
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p.copyResponse(rw, res.Body)
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}
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@ -260,7 +222,6 @@ func (p *ReverseProxy) copyResponse(dst io.Writer, src io.Reader) {
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dst = mlw
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}
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}
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io.Copy(dst, src)
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}
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