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Diffstat (limited to 'modules/caddyhttp/reverseproxy/reverseproxy.go')
-rw-r--r--[-rwxr-xr-x]modules/caddyhttp/reverseproxy/reverseproxy.go846
1 files changed, 566 insertions, 280 deletions
diff --git a/modules/caddyhttp/reverseproxy/reverseproxy.go b/modules/caddyhttp/reverseproxy/reverseproxy.go
index 68393de..e312d71 100755..100644
--- a/modules/caddyhttp/reverseproxy/reverseproxy.go
+++ b/modules/caddyhttp/reverseproxy/reverseproxy.go
@@ -15,7 +15,9 @@
package reverseproxy
import (
+ "bytes"
"context"
+ "encoding/json"
"fmt"
"io"
"log"
@@ -24,219 +26,229 @@ import (
"net/url"
"strings"
"sync"
+ "sync/atomic"
"time"
+ "github.com/caddyserver/caddy/v2"
+ "github.com/caddyserver/caddy/v2/modules/caddyhttp"
"golang.org/x/net/http/httpguts"
)
-// 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 must not access the provided Request
- // after returning.
- 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.
- // A negative value means to flush immediately
- // after each write to the client.
- // The FlushInterval is ignored when ReverseProxy
- // recognizes a response as a streaming response;
- // for such responses, writes are flushed to the client
- // immediately.
- FlushInterval time.Duration
-
- // ErrorLog specifies an optional logger for errors
- // that occur when attempting to proxy the request.
- // If nil, logging goes to os.Stderr via the log package's
- // standard logger.
- ErrorLog *log.Logger
-
- // BufferPool optionally specifies a buffer pool to
- // get byte slices for use by io.CopyBuffer when
- // copying HTTP response bodies.
- BufferPool BufferPool
-
- // ModifyResponse is an optional function that modifies the
- // Response from the backend. It is called if the backend
- // returns a response at all, with any HTTP status code.
- // If the backend is unreachable, the optional ErrorHandler is
- // called without any call to ModifyResponse.
- //
- // If ModifyResponse returns an error, ErrorHandler is called
- // with its error value. If ErrorHandler is nil, its default
- // implementation is used.
- ModifyResponse func(*http.Response) error
-
- // ErrorHandler is an optional function that handles errors
- // reaching the backend or errors from ModifyResponse.
- //
- // If nil, the default is to log the provided error and return
- // a 502 Status Bad Gateway response.
- ErrorHandler func(http.ResponseWriter, *http.Request, error)
-}
-
-// A BufferPool is an interface for getting and returning temporary
-// byte slices for use by io.CopyBuffer.
-type BufferPool interface {
- Get() []byte
- Put([]byte)
+func init() {
+ caddy.RegisterModule(Handler{})
}
-func singleJoiningSlash(a, b string) string {
- aslash := strings.HasSuffix(a, "/")
- bslash := strings.HasPrefix(b, "/")
- switch {
- case aslash && bslash:
- return a + b[1:]
- case !aslash && !bslash:
- return a + "/" + b
+type Handler struct {
+ TransportRaw json.RawMessage `json:"transport,omitempty"`
+ LoadBalancing *LoadBalancing `json:"load_balancing,omitempty"`
+ HealthChecks *HealthChecks `json:"health_checks,omitempty"`
+ // UpstreamStorageRaw json.RawMessage `json:"upstream_storage,omitempty"` // TODO:
+ Upstreams HostPool `json:"upstreams,omitempty"`
+
+ // UpstreamProvider UpstreamProvider `json:"-"` // TODO:
+ Transport http.RoundTripper `json:"-"`
+}
+
+// CaddyModule returns the Caddy module information.
+func (Handler) CaddyModule() caddy.ModuleInfo {
+ return caddy.ModuleInfo{
+ Name: "http.handlers.reverse_proxy",
+ New: func() caddy.Module { return new(Handler) },
}
- return a + b
}
-// NewSingleHostReverseProxy returns a new ReverseProxy that routes
-// 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.
-// NewSingleHostReverseProxy does not rewrite the Host header.
-// To rewrite Host headers, use ReverseProxy directly with a custom
-// Director policy.
-func NewSingleHostReverseProxy(target *url.URL) *ReverseProxy {
- targetQuery := target.RawQuery
- director := func(req *http.Request) {
- req.URL.Scheme = target.Scheme
- req.URL.Host = target.Host
- req.URL.Path = singleJoiningSlash(target.Path, req.URL.Path)
- if targetQuery == "" || req.URL.RawQuery == "" {
- req.URL.RawQuery = targetQuery + req.URL.RawQuery
- } else {
- req.URL.RawQuery = targetQuery + "&" + req.URL.RawQuery
+func (h *Handler) Provision(ctx caddy.Context) error {
+ if h.TransportRaw != nil {
+ val, err := ctx.LoadModuleInline("protocol", "http.handlers.reverse_proxy.transport", h.TransportRaw)
+ if err != nil {
+ return fmt.Errorf("loading transport module: %s", err)
}
- if _, ok := req.Header["User-Agent"]; !ok {
- // explicitly disable User-Agent so it's not set to default value
- req.Header.Set("User-Agent", "")
+ h.Transport = val.(http.RoundTripper)
+ h.TransportRaw = nil // allow GC to deallocate - TODO: Does this help?
+ }
+ if h.LoadBalancing != nil && h.LoadBalancing.SelectionPolicyRaw != nil {
+ val, err := ctx.LoadModuleInline("policy",
+ "http.handlers.reverse_proxy.selection_policies",
+ h.LoadBalancing.SelectionPolicyRaw)
+ if err != nil {
+ return fmt.Errorf("loading load balancing selection module: %s", err)
}
+ h.LoadBalancing.SelectionPolicy = val.(Selector)
+ h.LoadBalancing.SelectionPolicyRaw = nil // allow GC to deallocate - TODO: Does this help?
}
- return &ReverseProxy{Director: director}
-}
-func copyHeader(dst, src http.Header) {
- for k, vv := range src {
- for _, v := range vv {
- dst.Add(k, v)
- }
+ if h.Transport == nil {
+ h.Transport = defaultTransport
}
-}
-func cloneHeader(h http.Header) http.Header {
- h2 := make(http.Header, len(h))
- for k, vv := range h {
- vv2 := make([]string, len(vv))
- copy(vv2, vv)
- h2[k] = vv2
+ if h.LoadBalancing == nil {
+ h.LoadBalancing = new(LoadBalancing)
+ }
+ if h.LoadBalancing.SelectionPolicy == nil {
+ h.LoadBalancing.SelectionPolicy = RandomSelection{}
+ }
+ if h.LoadBalancing.TryDuration > 0 && h.LoadBalancing.TryInterval == 0 {
+ // a non-zero try_duration with a zero try_interval
+ // will always spin the CPU for try_duration if the
+ // upstream is local or low-latency; default to some
+ // sane waiting period before try attempts
+ h.LoadBalancing.TryInterval = caddy.Duration(250 * time.Millisecond)
}
- return h2
-}
-// Hop-by-hop headers. These are removed when sent to the backend.
-// As of RFC 7230, hop-by-hop headers are required to appear in the
-// Connection header field. These are the headers defined by the
-// obsoleted RFC 2616 (section 13.5.1) and are used for backward
-// compatibility.
-var hopHeaders = []string{
- "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; https://www.rfc-editor.org/errata_search.php?eid=4522
- "Transfer-Encoding",
- "Upgrade",
-}
+ for _, upstream := range h.Upstreams {
+ // url parser requires a scheme
+ if !strings.Contains(upstream.Address, "://") {
+ upstream.Address = "http://" + upstream.Address
+ }
+ u, err := url.Parse(upstream.Address)
+ if err != nil {
+ return fmt.Errorf("invalid upstream address %s: %v", upstream.Address, err)
+ }
+ upstream.hostURL = u
+
+ // if host already exists from a current config,
+ // use that instead; otherwise, add it
+ // TODO: make hosts modular, so that their state can be distributed in enterprise for example
+ // TODO: If distributed, the pool should be stored in storage...
+ var host Host = new(upstreamHost)
+ activeHost, loaded := hosts.LoadOrStore(u.String(), host)
+ if loaded {
+ host = activeHost.(Host)
+ }
+ upstream.Host = host
+
+ // if the passive health checker has a non-zero "unhealthy
+ // request count" but the upstream has no MaxRequests set
+ // (they are the same thing, but one is a default value for
+ // for upstreams with a zero MaxRequests), copy the default
+ // value into this upstream, since the value in the upstream
+ // is what is used during availability checks
+ if h.HealthChecks != nil &&
+ h.HealthChecks.Passive != nil &&
+ h.HealthChecks.Passive.UnhealthyRequestCount > 0 &&
+ upstream.MaxRequests == 0 {
+ upstream.MaxRequests = h.HealthChecks.Passive.UnhealthyRequestCount
+ }
-func (p *ReverseProxy) defaultErrorHandler(rw http.ResponseWriter, req *http.Request, err error) {
- p.logf("http: proxy error: %v", err)
- rw.WriteHeader(http.StatusBadGateway)
-}
+ // TODO: active health checks
-func (p *ReverseProxy) getErrorHandler() func(http.ResponseWriter, *http.Request, error) {
- if p.ErrorHandler != nil {
- return p.ErrorHandler
+ if h.HealthChecks != nil {
+ // upstreams need independent access to the passive
+ // health check policy so they can, you know, passively
+ // do health checks
+ upstream.healthCheckPolicy = h.HealthChecks.Passive
+ }
}
- return p.defaultErrorHandler
+
+ return nil
}
-// modifyResponse conditionally runs the optional ModifyResponse hook
-// and reports whether the request should proceed.
-func (p *ReverseProxy) modifyResponse(rw http.ResponseWriter, res *http.Response, req *http.Request) bool {
- if p.ModifyResponse == nil {
- return true
- }
- if err := p.ModifyResponse(res); err != nil {
- res.Body.Close()
- p.getErrorHandler()(rw, req, err)
- return false
+func (h *Handler) Cleanup() error {
+ // TODO: finish this up, make sure it takes care of any active health checkers or whatever
+ for _, upstream := range h.Upstreams {
+ hosts.Delete(upstream.hostURL.String())
}
- return true
+ return nil
}
-func (p *ReverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) (*http.Response, error) {
- transport := p.Transport
- if transport == nil {
- transport = http.DefaultTransport
+func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
+ // prepare the request for proxying; this is needed only once
+ err := h.prepareRequest(r)
+ if err != nil {
+ return caddyhttp.Error(http.StatusInternalServerError,
+ fmt.Errorf("preparing request for upstream round-trip: %v", err))
}
- ctx := req.Context()
- if cn, ok := rw.(http.CloseNotifier); ok {
- var cancel context.CancelFunc
- ctx, cancel = context.WithCancel(ctx)
- defer cancel()
- notifyChan := cn.CloseNotify()
- go func() {
- select {
- case <-notifyChan:
- cancel()
- case <-ctx.Done():
+ start := time.Now()
+
+ var proxyErr error
+ for {
+ // choose an available upstream
+ upstream := h.LoadBalancing.SelectionPolicy.Select(h.Upstreams, r)
+ if upstream == nil {
+ if proxyErr == nil {
+ proxyErr = fmt.Errorf("no available upstreams")
+ }
+ if !h.tryAgain(start, proxyErr) {
+ break
}
- }()
+ continue
+ }
+
+ // proxy the request to that upstream
+ proxyErr = h.reverseProxy(w, r, upstream)
+ if proxyErr == nil {
+ return nil
+ }
+
+ // remember this failure (if enabled)
+ h.countFailure(upstream)
+
+ // if we've tried long enough, break
+ if !h.tryAgain(start, proxyErr) {
+ break
+ }
}
- outreq := req.WithContext(ctx) // includes shallow copies of maps, but okay
+ return caddyhttp.Error(http.StatusBadGateway, proxyErr)
+}
+
+// prepareRequest modifies req so that it is ready to be proxied,
+// except for directing to a specific upstream. This method mutates
+// headers and other necessary properties of the request and should
+// be done just once (before proxying) regardless of proxy retries.
+// This assumes that no mutations of the request are performed
+// by h during or after proxying.
+func (h Handler) prepareRequest(req *http.Request) error {
+ // ctx := req.Context()
+ // TODO: do we need to support CloseNotifier? It was deprecated years ago.
+ // All this does is wrap CloseNotify with context cancel, for those responsewriters
+ // which didn't support context, but all the ones we'd use should nowadays, right?
+ // if cn, ok := rw.(http.CloseNotifier); ok {
+ // var cancel context.CancelFunc
+ // ctx, cancel = context.WithCancel(ctx)
+ // defer cancel()
+ // notifyChan := cn.CloseNotify()
+ // go func() {
+ // select {
+ // case <-notifyChan:
+ // cancel()
+ // case <-ctx.Done():
+ // }
+ // }()
+ // }
+
+ // TODO: do we need to call WithContext, since we won't be changing req.Context() above if we remove the CloseNotifier stuff?
+ // TODO: (This is where references to req were originally "outreq", a shallow clone, which I think is unnecessary in our case)
+ // req = req.WithContext(ctx) // includes shallow copies of maps, but okay
if req.ContentLength == 0 {
- outreq.Body = nil // Issue 16036: nil Body for http.Transport retries
+ req.Body = nil // Issue golang/go#16036: nil Body for http.Transport retries
}
- outreq.Header = cloneHeader(req.Header)
+ // TODO: is this needed?
+ // req.Header = cloneHeader(req.Header)
- p.Director(outreq)
- outreq.Close = false
+ req.Close = false
- reqUpType := upgradeType(outreq.Header)
- removeConnectionHeaders(outreq.Header)
+ // if User-Agent is not set by client, then explicitly
+ // disable it so it's not set to default value by std lib
+ if _, ok := req.Header["User-Agent"]; !ok {
+ req.Header.Set("User-Agent", "")
+ }
+
+ reqUpType := upgradeType(req.Header)
+ removeConnectionHeaders(req.Header)
// 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.
for _, h := range hopHeaders {
- hv := outreq.Header.Get(h)
+ hv := req.Header.Get(h)
if hv == "" {
continue
}
if h == "Te" && hv == "trailers" {
- // Issue 21096: tell backend applications that
+ // Issue golang/go#21096: tell backend applications that
// care about trailer support that we support
// trailers. (We do, but we don't go out of
// our way to advertise that unless the
@@ -244,40 +256,65 @@ func (p *ReverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) (*ht
// worth mentioning)
continue
}
- outreq.Header.Del(h)
+ req.Header.Del(h)
}
// After stripping all the hop-by-hop connection headers above, add back any
// necessary for protocol upgrades, such as for websockets.
if reqUpType != "" {
- outreq.Header.Set("Connection", "Upgrade")
- outreq.Header.Set("Upgrade", reqUpType)
+ req.Header.Set("Connection", "Upgrade")
+ req.Header.Set("Upgrade", reqUpType)
}
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 {
+ if prior, ok := req.Header["X-Forwarded-For"]; ok {
clientIP = strings.Join(prior, ", ") + ", " + clientIP
}
- outreq.Header.Set("X-Forwarded-For", clientIP)
+ req.Header.Set("X-Forwarded-For", clientIP)
}
- res, err := transport.RoundTrip(outreq)
+ return nil
+}
+
+// TODO:
+// this code is the entry point to what was borrowed from the net/http/httputil package in the standard library.
+func (h *Handler) reverseProxy(rw http.ResponseWriter, req *http.Request, upstream *Upstream) error {
+ // TODO: count this active request
+
+ // point the request to this upstream
+ h.directRequest(req, upstream)
+
+ // do the round-trip
+ start := time.Now()
+ res, err := h.Transport.RoundTrip(req)
+ latency := time.Since(start)
if err != nil {
- p.getErrorHandler()(rw, outreq, err)
- return nil, err
+ return err
}
- // Deal with 101 Switching Protocols responses: (WebSocket, h2c, etc)
- if res.StatusCode == http.StatusSwitchingProtocols {
- if !p.modifyResponse(rw, res, outreq) {
- return res, nil
+ // perform passive health checks (if enabled)
+ if h.HealthChecks != nil && h.HealthChecks.Passive != nil {
+ // strike if the status code matches one that is "bad"
+ for _, badStatus := range h.HealthChecks.Passive.UnhealthyStatus {
+ if caddyhttp.StatusCodeMatches(res.StatusCode, badStatus) {
+ h.countFailure(upstream)
+ }
}
- p.handleUpgradeResponse(rw, outreq, res)
- return res, nil
+ // strike if the roundtrip took too long
+ if h.HealthChecks.Passive.UnhealthyLatency > 0 &&
+ latency >= time.Duration(h.HealthChecks.Passive.UnhealthyLatency) {
+ h.countFailure(upstream)
+ }
+ }
+
+ // Deal with 101 Switching Protocols responses: (WebSocket, h2c, etc)
+ if res.StatusCode == http.StatusSwitchingProtocols {
+ h.handleUpgradeResponse(rw, req, res)
+ return nil
}
removeConnectionHeaders(res.Header)
@@ -286,10 +323,6 @@ func (p *ReverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) (*ht
res.Header.Del(h)
}
- if !p.modifyResponse(rw, res, outreq) {
- return res, nil
- }
-
copyHeader(rw.Header(), res.Header)
// The "Trailer" header isn't included in the Transport's response,
@@ -305,15 +338,16 @@ func (p *ReverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) (*ht
rw.WriteHeader(res.StatusCode)
- err = p.copyResponse(rw, res.Body, p.flushInterval(req, res))
+ err = h.copyResponse(rw, res.Body, h.flushInterval(req, res))
if err != nil {
defer res.Body.Close()
// Since we're streaming the response, if we run into an error all we can do
- // is abort the request. Issue 23643: ReverseProxy should use ErrAbortHandler
+ // is abort the request. Issue golang/go#23643: ReverseProxy should use ErrAbortHandler
// on read error while copying body.
+ // TODO: Look into whether we want to panic at all in our case...
if !shouldPanicOnCopyError(req) {
- p.logf("suppressing panic for copyResponse error in test; copy error: %v", err)
- return nil, err
+ // p.logf("suppressing panic for copyResponse error in test; copy error: %v", err)
+ return err
}
panic(http.ErrAbortHandler)
@@ -331,7 +365,7 @@ func (p *ReverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) (*ht
if len(res.Trailer) == announcedTrailers {
copyHeader(rw.Header(), res.Trailer)
- return res, nil
+ return nil
}
for k, vv := range res.Trailer {
@@ -341,46 +375,90 @@ func (p *ReverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) (*ht
}
}
- return res, nil
+ return nil
}
-var inOurTests bool // whether we're in our own tests
-
-// shouldPanicOnCopyError reports whether the reverse proxy should
-// panic with http.ErrAbortHandler. This is the right thing to do by
-// default, but Go 1.10 and earlier did not, so existing unit tests
-// weren't expecting panics. Only panic in our own tests, or when
-// running under the HTTP server.
-func shouldPanicOnCopyError(req *http.Request) bool {
- if inOurTests {
- // Our tests know to handle this panic.
- return true
+// tryAgain takes the time that the handler was initially invoked
+// as well as any error currently obtained and returns true if
+// another attempt should be made at proxying the request. If
+// true is returned, it has already blocked long enough before
+// the next retry (i.e. no more sleeping is needed). If false is
+// returned, the handler should stop trying to proxy the request.
+func (h Handler) tryAgain(start time.Time, proxyErr error) bool {
+ // if downstream has canceled the request, break
+ if proxyErr == context.Canceled {
+ return false
}
- if req.Context().Value(http.ServerContextKey) != nil {
- // We seem to be running under an HTTP server, so
- // it'll recover the panic.
- return true
+ // if we've tried long enough, break
+ if time.Since(start) >= time.Duration(h.LoadBalancing.TryDuration) {
+ return false
}
- // Otherwise act like Go 1.10 and earlier to not break
- // existing tests.
- return false
+ // otherwise, wait and try the next available host
+ time.Sleep(time.Duration(h.LoadBalancing.TryInterval))
+ return true
}
-// removeConnectionHeaders removes hop-by-hop headers listed in the "Connection" header of h.
-// See RFC 7230, section 6.1
-func removeConnectionHeaders(h http.Header) {
- if c := h.Get("Connection"); c != "" {
- for _, f := range strings.Split(c, ",") {
- if f = strings.TrimSpace(f); f != "" {
- h.Del(f)
- }
- }
+// directRequest modifies only req.URL so that it points to the
+// given upstream host. It must modify ONLY the request URL.
+func (h Handler) directRequest(req *http.Request, upstream *Upstream) {
+ target := upstream.hostURL
+ req.URL.Scheme = target.Scheme
+ req.URL.Host = target.Host
+ req.URL.Path = singleJoiningSlash(target.Path, req.URL.Path) // TODO: This might be a bug (if any part of the path was augmented from a previously-tried upstream; need to start from clean original path of request, same for query string!)
+ if target.RawQuery == "" || req.URL.RawQuery == "" {
+ req.URL.RawQuery = target.RawQuery + req.URL.RawQuery
+ } else {
+ req.URL.RawQuery = target.RawQuery + "&" + req.URL.RawQuery
}
}
+func (h Handler) handleUpgradeResponse(rw http.ResponseWriter, req *http.Request, res *http.Response) {
+ reqUpType := upgradeType(req.Header)
+ resUpType := upgradeType(res.Header)
+ if reqUpType != resUpType {
+ // p.getErrorHandler()(rw, req, fmt.Errorf("backend tried to switch protocol %q when %q was requested", resUpType, reqUpType))
+ return
+ }
+
+ copyHeader(res.Header, rw.Header())
+
+ hj, ok := rw.(http.Hijacker)
+ if !ok {
+ // p.getErrorHandler()(rw, req, fmt.Errorf("can't switch protocols using non-Hijacker ResponseWriter type %T", rw))
+ return
+ }
+ backConn, ok := res.Body.(io.ReadWriteCloser)
+ if !ok {
+ // p.getErrorHandler()(rw, req, fmt.Errorf("internal error: 101 switching protocols response with non-writable body"))
+ return
+ }
+ defer backConn.Close()
+ conn, brw, err := hj.Hijack()
+ if err != nil {
+ // p.getErrorHandler()(rw, req, fmt.Errorf("Hijack failed on protocol switch: %v", err))
+ return
+ }
+ defer conn.Close()
+ res.Body = nil // so res.Write only writes the headers; we have res.Body in backConn above
+ if err := res.Write(brw); err != nil {
+ // p.getErrorHandler()(rw, req, fmt.Errorf("response write: %v", err))
+ return
+ }
+ if err := brw.Flush(); err != nil {
+ // p.getErrorHandler()(rw, req, fmt.Errorf("response flush: %v", err))
+ return
+ }
+ errc := make(chan error, 1)
+ spc := switchProtocolCopier{user: conn, backend: backConn}
+ go spc.copyToBackend(errc)
+ go spc.copyFromBackend(errc)
+ <-errc
+ return
+}
+
// flushInterval returns the p.FlushInterval value, conditionally
// overriding its value for a specific request/response.
-func (p *ReverseProxy) flushInterval(req *http.Request, res *http.Response) time.Duration {
+func (h Handler) flushInterval(req *http.Request, res *http.Response) time.Duration {
resCT := res.Header.Get("Content-Type")
// For Server-Sent Events responses, flush immediately.
@@ -390,10 +468,11 @@ func (p *ReverseProxy) flushInterval(req *http.Request, res *http.Response) time
}
// TODO: more specific cases? e.g. res.ContentLength == -1?
- return p.FlushInterval
+ // return h.FlushInterval
+ return 0
}
-func (p *ReverseProxy) copyResponse(dst io.Writer, src io.Reader, flushInterval time.Duration) error {
+func (h Handler) copyResponse(dst io.Writer, src io.Reader, flushInterval time.Duration) error {
if flushInterval != 0 {
if wf, ok := dst.(writeFlusher); ok {
mlw := &maxLatencyWriter{
@@ -405,18 +484,25 @@ func (p *ReverseProxy) copyResponse(dst io.Writer, src io.Reader, flushInterval
}
}
+ // TODO: Figure out how we want to do this... using custom buffer pool type seems unnecessary
+ // or maybe it is, depending on how we want to handle errors,
+ // see: https://github.com/golang/go/issues/21814
+ // buf := bufPool.Get().(*bytes.Buffer)
+ // buf.Reset()
+ // defer bufPool.Put(buf)
+ // _, err := io.CopyBuffer(dst, src, )
var buf []byte
- if p.BufferPool != nil {
- buf = p.BufferPool.Get()
- defer p.BufferPool.Put(buf)
- }
- _, err := p.copyBuffer(dst, src, buf)
+ // if h.BufferPool != nil {
+ // buf = h.BufferPool.Get()
+ // defer h.BufferPool.Put(buf)
+ // }
+ _, err := h.copyBuffer(dst, src, buf)
return err
}
// copyBuffer returns any write errors or non-EOF read errors, and the amount
// of bytes written.
-func (p *ReverseProxy) copyBuffer(dst io.Writer, src io.Reader, buf []byte) (int64, error) {
+func (h Handler) copyBuffer(dst io.Writer, src io.Reader, buf []byte) (int64, error) {
if len(buf) == 0 {
buf = make([]byte, 32*1024)
}
@@ -424,7 +510,13 @@ func (p *ReverseProxy) copyBuffer(dst io.Writer, src io.Reader, buf []byte) (int
for {
nr, rerr := src.Read(buf)
if rerr != nil && rerr != io.EOF && rerr != context.Canceled {
- p.logf("httputil: ReverseProxy read error during body copy: %v", rerr)
+ // TODO: this could be useful to know (indeed, it revealed an error in our
+ // fastcgi PoC earlier; but it's this single error report here that necessitates
+ // a function separate from io.CopyBuffer, since io.CopyBuffer does not distinguish
+ // between read or write errors; in a reverse proxy situation, write errors are not
+ // something we need to report to the client, but read errors are a problem on our
+ // end for sure. so we need to decide what we want.)
+ // p.logf("copyBuffer: ReverseProxy read error during body copy: %v", rerr)
}
if nr > 0 {
nw, werr := dst.Write(buf[:nr])
@@ -447,12 +539,36 @@ func (p *ReverseProxy) copyBuffer(dst io.Writer, src io.Reader, buf []byte) (int
}
}
-func (p *ReverseProxy) logf(format string, args ...interface{}) {
- if p.ErrorLog != nil {
- p.ErrorLog.Printf(format, args...)
- } else {
- log.Printf(format, args...)
+// countFailure remembers 1 failure for upstream for the
+// configured duration. If passive health checks are
+// disabled or failure expiry is 0, this is a no-op.
+func (h Handler) countFailure(upstream *Upstream) {
+ // only count failures if passive health checking is enabled
+ // and if failures are configured have a non-zero expiry
+ if h.HealthChecks == nil || h.HealthChecks.Passive == nil {
+ return
+ }
+ failDuration := time.Duration(h.HealthChecks.Passive.FailDuration)
+ if failDuration == 0 {
+ return
+ }
+
+ // count failure immediately
+ err := upstream.Host.CountFail(1)
+ if err != nil {
+ log.Printf("[ERROR] proxy: upstream %s: counting failure: %v",
+ upstream.hostURL, err)
}
+
+ // forget it later
+ go func(host Host, failDuration time.Duration) {
+ time.Sleep(failDuration)
+ err := host.CountFail(-1)
+ if err != nil {
+ log.Printf("[ERROR] proxy: upstream %s: expiring failure: %v",
+ upstream.hostURL, err)
+ }
+ }(upstream.Host, failDuration)
}
type writeFlusher interface {
@@ -508,6 +624,61 @@ func (m *maxLatencyWriter) stop() {
}
}
+// switchProtocolCopier exists so goroutines proxying data back and
+// forth have nice names in stacks.
+type switchProtocolCopier struct {
+ user, backend io.ReadWriter
+}
+
+func (c switchProtocolCopier) copyFromBackend(errc chan<- error) {
+ _, err := io.Copy(c.user, c.backend)
+ errc <- err
+}
+
+func (c switchProtocolCopier) copyToBackend(errc chan<- error) {
+ _, err := io.Copy(c.backend, c.user)
+ errc <- err
+}
+
+// shouldPanicOnCopyError reports whether the reverse proxy should
+// panic with http.ErrAbortHandler. This is the right thing to do by
+// default, but Go 1.10 and earlier did not, so existing unit tests
+// weren't expecting panics. Only panic in our own tests, or when
+// running under the HTTP server.
+// TODO: I don't know if we want this at all...
+func shouldPanicOnCopyError(req *http.Request) bool {
+ // if inOurTests {
+ // // Our tests know to handle this panic.
+ // return true
+ // }
+ if req.Context().Value(http.ServerContextKey) != nil {
+ // We seem to be running under an HTTP server, so
+ // it'll recover the panic.
+ return true
+ }
+ // Otherwise act like Go 1.10 and earlier to not break
+ // existing tests.
+ return false
+}
+
+func copyHeader(dst, src http.Header) {
+ for k, vv := range src {
+ for _, v := range vv {
+ dst.Add(k, v)
+ }
+ }
+}
+
+func cloneHeader(h http.Header) http.Header {
+ h2 := make(http.Header, len(h))
+ for k, vv := range h {
+ vv2 := make([]string, len(vv))
+ copy(vv2, vv)
+ h2[k] = vv2
+ }
+ return h2
+}
+
func upgradeType(h http.Header) string {
if !httpguts.HeaderValuesContainsToken(h["Connection"], "Upgrade") {
return ""
@@ -515,62 +686,177 @@ func upgradeType(h http.Header) string {
return strings.ToLower(h.Get("Upgrade"))
}
-func (p *ReverseProxy) handleUpgradeResponse(rw http.ResponseWriter, req *http.Request, res *http.Response) {
- reqUpType := upgradeType(req.Header)
- resUpType := upgradeType(res.Header)
- if reqUpType != resUpType {
- p.getErrorHandler()(rw, req, fmt.Errorf("backend tried to switch protocol %q when %q was requested", resUpType, reqUpType))
- return
+func singleJoiningSlash(a, b string) string {
+ aslash := strings.HasSuffix(a, "/")
+ bslash := strings.HasPrefix(b, "/")
+ switch {
+ case aslash && bslash:
+ return a + b[1:]
+ case !aslash && !bslash:
+ return a + "/" + b
}
+ return a + b
+}
- copyHeader(res.Header, rw.Header())
-
- hj, ok := rw.(http.Hijacker)
- if !ok {
- p.getErrorHandler()(rw, req, fmt.Errorf("can't switch protocols using non-Hijacker ResponseWriter type %T", rw))
- return
- }
- backConn, ok := res.Body.(io.ReadWriteCloser)
- if !ok {
- p.getErrorHandler()(rw, req, fmt.Errorf("internal error: 101 switching protocols response with non-writable body"))
- return
+// removeConnectionHeaders removes hop-by-hop headers listed in the "Connection" header of h.
+// See RFC 7230, section 6.1
+func removeConnectionHeaders(h http.Header) {
+ if c := h.Get("Connection"); c != "" {
+ for _, f := range strings.Split(c, ",") {
+ if f = strings.TrimSpace(f); f != "" {
+ h.Del(f)
+ }
+ }
}
- defer backConn.Close()
- conn, brw, err := hj.Hijack()
- if err != nil {
- p.getErrorHandler()(rw, req, fmt.Errorf("Hijack failed on protocol switch: %v", err))
- return
+}
+
+type LoadBalancing struct {
+ SelectionPolicyRaw json.RawMessage `json:"selection_policy,omitempty"`
+ TryDuration caddy.Duration `json:"try_duration,omitempty"`
+ TryInterval caddy.Duration `json:"try_interval,omitempty"`
+
+ SelectionPolicy Selector `json:"-"`
+}
+
+type Selector interface {
+ Select(HostPool, *http.Request) *Upstream
+}
+
+type HealthChecks struct {
+ Active *ActiveHealthChecks `json:"active,omitempty"`
+ Passive *PassiveHealthChecks `json:"passive,omitempty"`
+}
+
+type ActiveHealthChecks struct {
+ Path string `json:"path,omitempty"`
+ Port int `json:"port,omitempty"`
+ Interval caddy.Duration `json:"interval,omitempty"`
+ Timeout caddy.Duration `json:"timeout,omitempty"`
+ MaxSize int `json:"max_size,omitempty"`
+ ExpectStatus int `json:"expect_status,omitempty"`
+ ExpectBody string `json:"expect_body,omitempty"`
+}
+
+type PassiveHealthChecks struct {
+ MaxFails int `json:"max_fails,omitempty"`
+ FailDuration caddy.Duration `json:"fail_duration,omitempty"`
+ UnhealthyRequestCount int `json:"unhealthy_request_count,omitempty"`
+ UnhealthyStatus []int `json:"unhealthy_status,omitempty"`
+ UnhealthyLatency caddy.Duration `json:"unhealthy_latency,omitempty"`
+}
+
+// Hop-by-hop headers. These are removed when sent to the backend.
+// As of RFC 7230, hop-by-hop headers are required to appear in the
+// Connection header field. These are the headers defined by the
+// obsoleted RFC 2616 (section 13.5.1) and are used for backward
+// compatibility.
+var hopHeaders = []string{
+ "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; https://www.rfc-editor.org/errata_search.php?eid=4522
+ "Transfer-Encoding",
+ "Upgrade",
+}
+
+var bufPool = sync.Pool{
+ New: func() interface{} {
+ return new(bytes.Buffer)
+ },
+}
+
+//////////////////////////////////
+// TODO:
+
+type Host interface {
+ NumRequests() int
+ Fails() int
+ Unhealthy() bool
+
+ CountRequest(int) error
+ CountFail(int) error
+}
+
+type HostPool []*Upstream
+
+type upstreamHost struct {
+ numRequests int64 // must be first field to be 64-bit aligned on 32-bit systems (see https://golang.org/pkg/sync/atomic/#pkg-note-BUG)
+ fails int64
+ unhealthy int32
+}
+
+func (uh upstreamHost) NumRequests() int {
+ return int(atomic.LoadInt64(&uh.numRequests))
+}
+func (uh upstreamHost) Fails() int {
+ return int(atomic.LoadInt64(&uh.fails))
+}
+func (uh upstreamHost) Unhealthy() bool {
+ return atomic.LoadInt32(&uh.unhealthy) == 1
+}
+func (uh *upstreamHost) CountRequest(delta int) error {
+ result := atomic.AddInt64(&uh.numRequests, int64(delta))
+ if result < 0 {
+ return fmt.Errorf("count below 0: %d", result)
}
- defer conn.Close()
- res.Body = nil // so res.Write only writes the headers; we have res.Body in backConn above
- if err := res.Write(brw); err != nil {
- p.getErrorHandler()(rw, req, fmt.Errorf("response write: %v", err))
- return
+ return nil
+}
+func (uh *upstreamHost) CountFail(delta int) error {
+ result := atomic.AddInt64(&uh.fails, int64(delta))
+ if result < 0 {
+ return fmt.Errorf("count below 0: %d", result)
}
- if err := brw.Flush(); err != nil {
- p.getErrorHandler()(rw, req, fmt.Errorf("response flush: %v", err))
- return
+ return nil
+}
+
+type Upstream struct {
+ Host `json:"-"`
+
+ Address string `json:"address,omitempty"`
+ MaxRequests int `json:"max_requests,omitempty"`
+
+ // TODO: This could be really cool, to say that requests with
+ // certain headers or from certain IPs always go to this upstream
+ // HeaderAffinity string
+ // IPAffinity string
+
+ healthCheckPolicy *PassiveHealthChecks
+
+ hostURL *url.URL
+}
+
+func (u Upstream) Available() bool {
+ return u.Healthy() && !u.Full()
+}
+
+func (u Upstream) Healthy() bool {
+ healthy := !u.Host.Unhealthy()
+ if healthy && u.healthCheckPolicy != nil {
+ healthy = u.Host.Fails() < u.healthCheckPolicy.MaxFails
}
- errc := make(chan error, 1)
- spc := switchProtocolCopier{user: conn, backend: backConn}
- go spc.copyToBackend(errc)
- go spc.copyFromBackend(errc)
- <-errc
- return
+ return healthy
}
-// switchProtocolCopier exists so goroutines proxying data back and
-// forth have nice names in stacks.
-type switchProtocolCopier struct {
- user, backend io.ReadWriter
+func (u Upstream) Full() bool {
+ return u.MaxRequests > 0 && u.Host.NumRequests() >= u.MaxRequests
}
-func (c switchProtocolCopier) copyFromBackend(errc chan<- error) {
- _, err := io.Copy(c.user, c.backend)
- errc <- err
+func (u Upstream) URL() *url.URL {
+ return u.hostURL
}
-func (c switchProtocolCopier) copyToBackend(errc chan<- error) {
- _, err := io.Copy(c.backend, c.user)
- errc <- err
+var hosts = caddy.NewUsagePool()
+
+// TODO: ...
+type UpstreamProvider interface {
}
+
+// Interface guards
+var (
+ _ caddyhttp.MiddlewareHandler = (*Handler)(nil)
+ _ caddy.Provisioner = (*Handler)(nil)
+ _ caddy.CleanerUpper = (*Handler)(nil)
+)
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-10 23:26:28 +0000