mirror of
https://github.com/caddyserver/caddy.git
synced 2024-12-16 21:56:40 -05:00
862 lines
25 KiB
Go
862 lines
25 KiB
Go
// Copyright 2015 Matthew Holt and The Caddy Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package reverseproxy
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import (
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"bytes"
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"context"
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"encoding/json"
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"fmt"
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"io"
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"log"
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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"
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"sync/atomic"
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"time"
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"github.com/caddyserver/caddy/v2"
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"github.com/caddyserver/caddy/v2/modules/caddyhttp"
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"golang.org/x/net/http/httpguts"
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)
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func init() {
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caddy.RegisterModule(Handler{})
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}
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type Handler struct {
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TransportRaw json.RawMessage `json:"transport,omitempty"`
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LoadBalancing *LoadBalancing `json:"load_balancing,omitempty"`
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HealthChecks *HealthChecks `json:"health_checks,omitempty"`
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// UpstreamStorageRaw json.RawMessage `json:"upstream_storage,omitempty"` // TODO:
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Upstreams HostPool `json:"upstreams,omitempty"`
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// UpstreamProvider UpstreamProvider `json:"-"` // TODO:
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Transport http.RoundTripper `json:"-"`
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}
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// CaddyModule returns the Caddy module information.
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func (Handler) CaddyModule() caddy.ModuleInfo {
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return caddy.ModuleInfo{
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Name: "http.handlers.reverse_proxy",
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New: func() caddy.Module { return new(Handler) },
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}
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}
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func (h *Handler) Provision(ctx caddy.Context) error {
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if h.TransportRaw != nil {
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val, err := ctx.LoadModuleInline("protocol", "http.handlers.reverse_proxy.transport", h.TransportRaw)
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if err != nil {
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return fmt.Errorf("loading transport module: %s", err)
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}
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h.Transport = val.(http.RoundTripper)
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h.TransportRaw = nil // allow GC to deallocate - TODO: Does this help?
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}
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if h.LoadBalancing != nil && h.LoadBalancing.SelectionPolicyRaw != nil {
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val, err := ctx.LoadModuleInline("policy",
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"http.handlers.reverse_proxy.selection_policies",
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h.LoadBalancing.SelectionPolicyRaw)
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if err != nil {
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return fmt.Errorf("loading load balancing selection module: %s", err)
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}
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h.LoadBalancing.SelectionPolicy = val.(Selector)
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h.LoadBalancing.SelectionPolicyRaw = nil // allow GC to deallocate - TODO: Does this help?
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}
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if h.Transport == nil {
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h.Transport = defaultTransport
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}
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if h.LoadBalancing == nil {
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h.LoadBalancing = new(LoadBalancing)
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}
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if h.LoadBalancing.SelectionPolicy == nil {
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h.LoadBalancing.SelectionPolicy = RandomSelection{}
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}
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if h.LoadBalancing.TryDuration > 0 && h.LoadBalancing.TryInterval == 0 {
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// a non-zero try_duration with a zero try_interval
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// will always spin the CPU for try_duration if the
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// upstream is local or low-latency; default to some
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// sane waiting period before try attempts
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h.LoadBalancing.TryInterval = caddy.Duration(250 * time.Millisecond)
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}
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for _, upstream := range h.Upstreams {
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// url parser requires a scheme
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if !strings.Contains(upstream.Address, "://") {
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upstream.Address = "http://" + upstream.Address
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}
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u, err := url.Parse(upstream.Address)
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if err != nil {
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return fmt.Errorf("invalid upstream address %s: %v", upstream.Address, err)
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}
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upstream.hostURL = u
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// if host already exists from a current config,
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// use that instead; otherwise, add it
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// TODO: make hosts modular, so that their state can be distributed in enterprise for example
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// TODO: If distributed, the pool should be stored in storage...
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var host Host = new(upstreamHost)
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activeHost, loaded := hosts.LoadOrStore(u.String(), host)
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if loaded {
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host = activeHost.(Host)
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}
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upstream.Host = host
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// if the passive health checker has a non-zero "unhealthy
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// request count" but the upstream has no MaxRequests set
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// (they are the same thing, but one is a default value for
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// for upstreams with a zero MaxRequests), copy the default
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// value into this upstream, since the value in the upstream
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// is what is used during availability checks
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if h.HealthChecks != nil &&
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h.HealthChecks.Passive != nil &&
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h.HealthChecks.Passive.UnhealthyRequestCount > 0 &&
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upstream.MaxRequests == 0 {
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upstream.MaxRequests = h.HealthChecks.Passive.UnhealthyRequestCount
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}
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// TODO: active health checks
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if h.HealthChecks != nil {
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// upstreams need independent access to the passive
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// health check policy so they can, you know, passively
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// do health checks
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upstream.healthCheckPolicy = h.HealthChecks.Passive
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}
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}
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return nil
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}
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func (h *Handler) Cleanup() error {
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// TODO: finish this up, make sure it takes care of any active health checkers or whatever
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for _, upstream := range h.Upstreams {
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hosts.Delete(upstream.hostURL.String())
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}
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return nil
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}
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func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
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// prepare the request for proxying; this is needed only once
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err := h.prepareRequest(r)
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if err != nil {
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return caddyhttp.Error(http.StatusInternalServerError,
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fmt.Errorf("preparing request for upstream round-trip: %v", err))
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}
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start := time.Now()
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var proxyErr error
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for {
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// choose an available upstream
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upstream := h.LoadBalancing.SelectionPolicy.Select(h.Upstreams, r)
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if upstream == nil {
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if proxyErr == nil {
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proxyErr = fmt.Errorf("no available upstreams")
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}
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if !h.tryAgain(start, proxyErr) {
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break
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}
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continue
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}
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// proxy the request to that upstream
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proxyErr = h.reverseProxy(w, r, upstream)
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if proxyErr == nil {
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return nil
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}
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// remember this failure (if enabled)
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h.countFailure(upstream)
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// if we've tried long enough, break
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if !h.tryAgain(start, proxyErr) {
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break
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}
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}
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return caddyhttp.Error(http.StatusBadGateway, proxyErr)
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}
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// prepareRequest modifies req so that it is ready to be proxied,
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// except for directing to a specific upstream. This method mutates
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// headers and other necessary properties of the request and should
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// be done just once (before proxying) regardless of proxy retries.
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// This assumes that no mutations of the request are performed
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// by h during or after proxying.
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func (h Handler) prepareRequest(req *http.Request) error {
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// ctx := req.Context()
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// TODO: do we need to support CloseNotifier? It was deprecated years ago.
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// All this does is wrap CloseNotify with context cancel, for those responsewriters
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// which didn't support context, but all the ones we'd use should nowadays, right?
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// if cn, ok := rw.(http.CloseNotifier); ok {
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// var cancel context.CancelFunc
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// ctx, cancel = context.WithCancel(ctx)
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// defer cancel()
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// notifyChan := cn.CloseNotify()
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// go func() {
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// select {
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// case <-notifyChan:
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// cancel()
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// case <-ctx.Done():
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// }
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// }()
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// }
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// TODO: do we need to call WithContext, since we won't be changing req.Context() above if we remove the CloseNotifier stuff?
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// TODO: (This is where references to req were originally "outreq", a shallow clone, which I think is unnecessary in our case)
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// req = req.WithContext(ctx) // includes shallow copies of maps, but okay
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if req.ContentLength == 0 {
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req.Body = nil // Issue golang/go#16036: nil Body for http.Transport retries
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}
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// TODO: is this needed?
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// req.Header = cloneHeader(req.Header)
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req.Close = false
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// if User-Agent is not set by client, then explicitly
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// disable it so it's not set to default value by std lib
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if _, ok := req.Header["User-Agent"]; !ok {
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req.Header.Set("User-Agent", "")
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}
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reqUpType := upgradeType(req.Header)
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removeConnectionHeaders(req.Header)
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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.
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for _, h := range hopHeaders {
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hv := req.Header.Get(h)
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if hv == "" {
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continue
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}
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if h == "Te" && hv == "trailers" {
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// Issue golang/go#21096: tell backend applications that
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// care about trailer support that we support
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// trailers. (We do, but we don't go out of
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// our way to advertise that unless the
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// incoming client request thought it was
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// worth mentioning)
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continue
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}
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req.Header.Del(h)
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}
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// After stripping all the hop-by-hop connection headers above, add back any
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// necessary for protocol upgrades, such as for websockets.
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if reqUpType != "" {
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req.Header.Set("Connection", "Upgrade")
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req.Header.Set("Upgrade", reqUpType)
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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 := req.Header["X-Forwarded-For"]; ok {
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clientIP = strings.Join(prior, ", ") + ", " + clientIP
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}
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req.Header.Set("X-Forwarded-For", clientIP)
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}
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return nil
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}
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// TODO:
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// this code is the entry point to what was borrowed from the net/http/httputil package in the standard library.
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func (h *Handler) reverseProxy(rw http.ResponseWriter, req *http.Request, upstream *Upstream) error {
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// TODO: count this active request
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// point the request to this upstream
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h.directRequest(req, upstream)
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// do the round-trip
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start := time.Now()
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res, err := h.Transport.RoundTrip(req)
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latency := time.Since(start)
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if err != nil {
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return err
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}
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// perform passive health checks (if enabled)
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if h.HealthChecks != nil && h.HealthChecks.Passive != nil {
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// strike if the status code matches one that is "bad"
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for _, badStatus := range h.HealthChecks.Passive.UnhealthyStatus {
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if caddyhttp.StatusCodeMatches(res.StatusCode, badStatus) {
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h.countFailure(upstream)
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}
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}
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// strike if the roundtrip took too long
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if h.HealthChecks.Passive.UnhealthyLatency > 0 &&
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latency >= time.Duration(h.HealthChecks.Passive.UnhealthyLatency) {
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h.countFailure(upstream)
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}
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}
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// Deal with 101 Switching Protocols responses: (WebSocket, h2c, etc)
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if res.StatusCode == http.StatusSwitchingProtocols {
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h.handleUpgradeResponse(rw, req, res)
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return nil
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}
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removeConnectionHeaders(res.Header)
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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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// The "Trailer" header isn't included in the Transport's response,
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// at least for *http.Transport. Build it up from Trailer.
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announcedTrailers := len(res.Trailer)
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if announcedTrailers > 0 {
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trailerKeys := make([]string, 0, len(res.Trailer))
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for k := range res.Trailer {
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trailerKeys = append(trailerKeys, k)
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}
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rw.Header().Add("Trailer", strings.Join(trailerKeys, ", "))
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}
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rw.WriteHeader(res.StatusCode)
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err = h.copyResponse(rw, res.Body, h.flushInterval(req, res))
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if err != nil {
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defer res.Body.Close()
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// Since we're streaming the response, if we run into an error all we can do
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// is abort the request. Issue golang/go#23643: ReverseProxy should use ErrAbortHandler
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// on read error while copying body.
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// TODO: Look into whether we want to panic at all in our case...
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if !shouldPanicOnCopyError(req) {
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// p.logf("suppressing panic for copyResponse error in test; copy error: %v", err)
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return err
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}
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panic(http.ErrAbortHandler)
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}
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res.Body.Close() // close now, instead of defer, to populate res.Trailer
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if len(res.Trailer) > 0 {
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// Force chunking if we saw a response trailer.
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// This prevents net/http from calculating the length for short
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// bodies and adding a Content-Length.
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if fl, ok := rw.(http.Flusher); ok {
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fl.Flush()
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}
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}
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if len(res.Trailer) == announcedTrailers {
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copyHeader(rw.Header(), res.Trailer)
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return nil
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}
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for k, vv := range res.Trailer {
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k = http.TrailerPrefix + k
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for _, v := range vv {
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rw.Header().Add(k, v)
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}
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}
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return nil
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}
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// tryAgain takes the time that the handler was initially invoked
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// as well as any error currently obtained and returns true if
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// another attempt should be made at proxying the request. If
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// true is returned, it has already blocked long enough before
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// the next retry (i.e. no more sleeping is needed). If false is
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// returned, the handler should stop trying to proxy the request.
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func (h Handler) tryAgain(start time.Time, proxyErr error) bool {
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// if downstream has canceled the request, break
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if proxyErr == context.Canceled {
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return false
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}
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// if we've tried long enough, break
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if time.Since(start) >= time.Duration(h.LoadBalancing.TryDuration) {
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return false
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}
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// otherwise, wait and try the next available host
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time.Sleep(time.Duration(h.LoadBalancing.TryInterval))
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return true
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}
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// directRequest modifies only req.URL so that it points to the
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// given upstream host. It must modify ONLY the request URL.
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func (h Handler) directRequest(req *http.Request, upstream *Upstream) {
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target := upstream.hostURL
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req.URL.Scheme = target.Scheme
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req.URL.Host = target.Host
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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!)
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if target.RawQuery == "" || req.URL.RawQuery == "" {
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req.URL.RawQuery = target.RawQuery + req.URL.RawQuery
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} else {
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req.URL.RawQuery = target.RawQuery + "&" + req.URL.RawQuery
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}
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}
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func (h Handler) handleUpgradeResponse(rw http.ResponseWriter, req *http.Request, res *http.Response) {
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reqUpType := upgradeType(req.Header)
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resUpType := upgradeType(res.Header)
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if reqUpType != resUpType {
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// p.getErrorHandler()(rw, req, fmt.Errorf("backend tried to switch protocol %q when %q was requested", resUpType, reqUpType))
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return
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}
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copyHeader(res.Header, rw.Header())
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hj, ok := rw.(http.Hijacker)
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if !ok {
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// p.getErrorHandler()(rw, req, fmt.Errorf("can't switch protocols using non-Hijacker ResponseWriter type %T", rw))
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return
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}
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backConn, ok := res.Body.(io.ReadWriteCloser)
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if !ok {
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// p.getErrorHandler()(rw, req, fmt.Errorf("internal error: 101 switching protocols response with non-writable body"))
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return
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}
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defer backConn.Close()
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conn, brw, err := hj.Hijack()
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if err != nil {
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// p.getErrorHandler()(rw, req, fmt.Errorf("Hijack failed on protocol switch: %v", err))
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return
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}
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defer conn.Close()
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res.Body = nil // so res.Write only writes the headers; we have res.Body in backConn above
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if err := res.Write(brw); err != nil {
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// p.getErrorHandler()(rw, req, fmt.Errorf("response write: %v", err))
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return
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}
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if err := brw.Flush(); err != nil {
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// p.getErrorHandler()(rw, req, fmt.Errorf("response flush: %v", err))
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return
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}
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errc := make(chan error, 1)
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spc := switchProtocolCopier{user: conn, backend: backConn}
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go spc.copyToBackend(errc)
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go spc.copyFromBackend(errc)
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<-errc
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return
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}
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// flushInterval returns the p.FlushInterval value, conditionally
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// overriding its value for a specific request/response.
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func (h Handler) flushInterval(req *http.Request, res *http.Response) time.Duration {
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resCT := res.Header.Get("Content-Type")
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// For Server-Sent Events responses, flush immediately.
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// The MIME type is defined in https://www.w3.org/TR/eventsource/#text-event-stream
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if resCT == "text/event-stream" {
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return -1 // negative means immediately
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}
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// TODO: more specific cases? e.g. res.ContentLength == -1?
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// return h.FlushInterval
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return 0
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}
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func (h Handler) copyResponse(dst io.Writer, src io.Reader, flushInterval time.Duration) error {
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if flushInterval != 0 {
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if wf, ok := dst.(writeFlusher); ok {
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mlw := &maxLatencyWriter{
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dst: wf,
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latency: flushInterval,
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}
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defer mlw.stop()
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dst = mlw
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}
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}
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// TODO: Figure out how we want to do this... using custom buffer pool type seems unnecessary
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// or maybe it is, depending on how we want to handle errors,
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// see: https://github.com/golang/go/issues/21814
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// buf := bufPool.Get().(*bytes.Buffer)
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// buf.Reset()
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// defer bufPool.Put(buf)
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// _, err := io.CopyBuffer(dst, src, )
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var buf []byte
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// if h.BufferPool != nil {
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// buf = h.BufferPool.Get()
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// defer h.BufferPool.Put(buf)
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// }
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_, err := h.copyBuffer(dst, src, buf)
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return err
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|
}
|
|
|
|
// copyBuffer returns any write errors or non-EOF read errors, and the amount
|
|
// of bytes written.
|
|
func (h Handler) copyBuffer(dst io.Writer, src io.Reader, buf []byte) (int64, error) {
|
|
if len(buf) == 0 {
|
|
buf = make([]byte, 32*1024)
|
|
}
|
|
var written int64
|
|
for {
|
|
nr, rerr := src.Read(buf)
|
|
if rerr != nil && rerr != io.EOF && rerr != context.Canceled {
|
|
// 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])
|
|
if nw > 0 {
|
|
written += int64(nw)
|
|
}
|
|
if werr != nil {
|
|
return written, werr
|
|
}
|
|
if nr != nw {
|
|
return written, io.ErrShortWrite
|
|
}
|
|
}
|
|
if rerr != nil {
|
|
if rerr == io.EOF {
|
|
rerr = nil
|
|
}
|
|
return written, rerr
|
|
}
|
|
}
|
|
}
|
|
|
|
// 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 {
|
|
io.Writer
|
|
http.Flusher
|
|
}
|
|
|
|
type maxLatencyWriter struct {
|
|
dst writeFlusher
|
|
latency time.Duration // non-zero; negative means to flush immediately
|
|
|
|
mu sync.Mutex // protects t, flushPending, and dst.Flush
|
|
t *time.Timer
|
|
flushPending bool
|
|
}
|
|
|
|
func (m *maxLatencyWriter) Write(p []byte) (n int, err error) {
|
|
m.mu.Lock()
|
|
defer m.mu.Unlock()
|
|
n, err = m.dst.Write(p)
|
|
if m.latency < 0 {
|
|
m.dst.Flush()
|
|
return
|
|
}
|
|
if m.flushPending {
|
|
return
|
|
}
|
|
if m.t == nil {
|
|
m.t = time.AfterFunc(m.latency, m.delayedFlush)
|
|
} else {
|
|
m.t.Reset(m.latency)
|
|
}
|
|
m.flushPending = true
|
|
return
|
|
}
|
|
|
|
func (m *maxLatencyWriter) delayedFlush() {
|
|
m.mu.Lock()
|
|
defer m.mu.Unlock()
|
|
if !m.flushPending { // if stop was called but AfterFunc already started this goroutine
|
|
return
|
|
}
|
|
m.dst.Flush()
|
|
m.flushPending = false
|
|
}
|
|
|
|
func (m *maxLatencyWriter) stop() {
|
|
m.mu.Lock()
|
|
defer m.mu.Unlock()
|
|
m.flushPending = false
|
|
if m.t != nil {
|
|
m.t.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 ""
|
|
}
|
|
return strings.ToLower(h.Get("Upgrade"))
|
|
}
|
|
|
|
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
|
|
}
|
|
|
|
// 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)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
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)
|
|
}
|
|
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)
|
|
}
|
|
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
|
|
}
|
|
return healthy
|
|
}
|
|
|
|
func (u Upstream) Full() bool {
|
|
return u.MaxRequests > 0 && u.Host.NumRequests() >= u.MaxRequests
|
|
}
|
|
|
|
func (u Upstream) URL() *url.URL {
|
|
return u.hostURL
|
|
}
|
|
|
|
var hosts = caddy.NewUsagePool()
|
|
|
|
// TODO: ...
|
|
type UpstreamProvider interface {
|
|
}
|
|
|
|
// Interface guards
|
|
var (
|
|
_ caddyhttp.MiddlewareHandler = (*Handler)(nil)
|
|
_ caddy.Provisioner = (*Handler)(nil)
|
|
_ caddy.CleanerUpper = (*Handler)(nil)
|
|
)
|