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Some cleanup and godoc

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This commit is contained in:
Matthew Holt 2019-09-03 16:56:09 -06:00
parent 4a1e1649bc
commit 652460e03e
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GPG key ID: 2A349DD577D586A5
6 changed files with 428 additions and 362 deletions
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12
modules/caddyhttp/reverseproxy/healthchecks.go
View file

@ -30,11 +30,15 @@ import (
"github.com/caddyserver/caddy/v2/modules/caddyhttp"
)
// HealthChecks holds configuration related to health checking.
type HealthChecks struct {
Active *ActiveHealthChecks `json:"active,omitempty"`
Passive *PassiveHealthChecks `json:"passive,omitempty"`
}
// ActiveHealthChecks holds configuration related to active
// health checks (that is, health checks which occur in a
// background goroutine independently).
type ActiveHealthChecks struct {
Path string `json:"path,omitempty"`
Port int `json:"port,omitempty"`
@ -49,6 +53,9 @@ type ActiveHealthChecks struct {
bodyRegexp *regexp.Regexp
}
// PassiveHealthChecks holds configuration related to passive
// health checks (that is, health checks which occur during
// the normal flow of request proxying).
type PassiveHealthChecks struct {
MaxFails int `json:"max_fails,omitempty"`
FailDuration caddy.Duration `json:"fail_duration,omitempty"`
@ -57,6 +64,9 @@ type PassiveHealthChecks struct {
UnhealthyLatency caddy.Duration `json:"unhealthy_latency,omitempty"`
}
// activeHealthChecker runs active health checks on a
// regular basis and blocks until
// h.HealthChecks.Active.stopChan is closed.
func (h *Handler) activeHealthChecker() {
ticker := time.NewTicker(time.Duration(h.HealthChecks.Active.Interval))
h.doActiveHealthChecksForAllHosts()
@ -71,6 +81,8 @@ func (h *Handler) activeHealthChecker() {
}
}
// doActiveHealthChecksForAllHosts immediately performs a
// health checks for all hosts in the global repository.
func (h *Handler) doActiveHealthChecksForAllHosts() {
hosts.Range(func(key, value interface{}) bool {
addr := key.(string)

161
modules/caddyhttp/reverseproxy/hosts.go Normal file
View file

@ -0,0 +1,161 @@
// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package reverseproxy
import (
"fmt"
"net/url"
"sync/atomic"
"github.com/caddyserver/caddy/v2"
)
// Host represents a remote host which can be proxied to.
// Its methods must be safe for concurrent use.
type Host interface {
// NumRequests returns the numnber of requests
// currently in process with the host.
NumRequests() int
// Fails returns the count of recent failures.
Fails() int
// Unhealthy returns true if the backend is unhealthy.
Unhealthy() bool
// CountRequest counts the given number of requests
// as currently in process with the host. The count
// should not go below 0.
CountRequest(int) error
// CountFail counts the given number of failures
// with the host. The count should not go below 0.
CountFail(int) error
// SetHealthy marks the host as either healthy (true)
// or unhealthy (false). If the given status is the
// same, this should be a no-op. It returns true if
// the given status was different, false otherwise.
SetHealthy(bool) (bool, error)
}
// UpstreamPool is a collection of upstreams.
type UpstreamPool []*Upstream
// Upstream bridges this proxy's configuration to the
// state of the backend host it is correlated with.
type Upstream struct {
Host `json:"-"`
Address string `json:"address,omitempty"`
MaxRequests int `json:"max_requests,omitempty"`
// TODO: This could be really useful, to bind requests
// with certain properties to specific backends
// HeaderAffinity string
// IPAffinity string
healthCheckPolicy *PassiveHealthChecks
hostURL *url.URL
}
// Available returns true if the remote host
// is available to receive requests.
func (u *Upstream) Available() bool {
return u.Healthy() && !u.Full()
}
// Healthy returns true if the remote host
// is currently known to be healthy or "up".
func (u *Upstream) Healthy() bool {
healthy := !u.Host.Unhealthy()
if healthy && u.healthCheckPolicy != nil {
healthy = u.Host.Fails() < u.healthCheckPolicy.MaxFails
}
return healthy
}
// Full returns true if the remote host
// cannot receive more requests at this time.
func (u *Upstream) Full() bool {
return u.MaxRequests > 0 && u.Host.NumRequests() >= u.MaxRequests
}
// URL returns the upstream host's endpoint URL.
func (u *Upstream) URL() *url.URL {
return u.hostURL
}
// upstreamHost is the basic, in-memory representation
// of the state of a remote host. It implements the
// Host interface.
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
}
// NumRequests returns the number of active requests to the upstream.
func (uh *upstreamHost) NumRequests() int {
return int(atomic.LoadInt64(&uh.numRequests))
}
// Fails returns the number of recent failures with the upstream.
func (uh *upstreamHost) Fails() int {
return int(atomic.LoadInt64(&uh.fails))
}
// Unhealthy returns whether the upstream is healthy.
func (uh *upstreamHost) Unhealthy() bool {
return atomic.LoadInt32(&uh.unhealthy) == 1
}
// CountRequest mutates the active request count by
// delta. It returns an error if the adjustment fails.
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
}
// CountFail mutates the recent failures count by
// delta. It returns an error if the adjustment fails.
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
}
// SetHealthy sets the upstream has healthy or unhealthy
// and returns true if the value was different from before,
// or an error if the adjustment failed.
func (uh *upstreamHost) SetHealthy(healthy bool) (bool, error) {
var unhealthy, compare int32 = 1, 0
if healthy {
unhealthy, compare = 0, 1
}
swapped := atomic.CompareAndSwapInt32(&uh.unhealthy, compare, unhealthy)
return swapped, nil
}
// hosts is the global repository for hosts that are
// currently in use by active configuration(s). This
// allows the state of remote hosts to be preserved
// through config reloads.
var hosts = caddy.NewUsagePool()

21
modules/caddyhttp/reverseproxy/httptransport.go
View file

@ -31,14 +31,13 @@ func init() {
caddy.RegisterModule(HTTPTransport{})
}
// TODO: This is the default transport, basically just http.Transport, but we define JSON struct tags...
// HTTPTransport is essentially a configuration wrapper for http.Transport.
// It defines a JSON structure useful when configuring the HTTP transport
// for Caddy's reverse proxy.
type HTTPTransport struct {
// TODO: Actually this is where the TLS config should go, technically...
// as well as keepalives and dial timeouts...
// TODO: It's possible that other transports (like fastcgi) might be
// able to borrow/use at least some of these config fields; if so,
// move them into a type called CommonTransport and embed it
TLS *TLSConfig `json:"tls,omitempty"`
KeepAlive *KeepAlive `json:"keep_alive,omitempty"`
Compression *bool `json:"compression,omitempty"`
@ -50,7 +49,6 @@ type HTTPTransport struct {
MaxResponseHeaderSize int64 `json:"max_response_header_size,omitempty"`
WriteBufferSize int `json:"write_buffer_size,omitempty"`
ReadBufferSize int `json:"read_buffer_size,omitempty"`
// TODO: ProxyConnectHeader?
RoundTripper http.RoundTripper `json:"-"`
}
@ -63,6 +61,8 @@ func (HTTPTransport) CaddyModule() caddy.ModuleInfo {
}
}
// Provision sets up h.RoundTripper with a http.Transport
// that is ready to use.
func (h *HTTPTransport) Provision(ctx caddy.Context) error {
dialer := &net.Dialer{
Timeout: time.Duration(h.DialTimeout),
@ -109,16 +109,13 @@ func (h *HTTPTransport) Provision(ctx caddy.Context) error {
return nil
}
// RoundTrip implements http.RoundTripper with h.RoundTripper.
func (h HTTPTransport) RoundTrip(req *http.Request) (*http.Response, error) {
return h.RoundTripper.RoundTrip(req)
}
func defaultTLSConfig() *tls.Config {
return &tls.Config{
NextProtos: []string{"h2", "http/1.1"}, // TODO: ensure this makes HTTP/2 work
}
}
// TLSConfig holds configuration related to the
// TLS configuration for the transport/client.
type TLSConfig struct {
RootCAPool []string `json:"root_ca_pool,omitempty"`
// TODO: Should the client cert+key config use caddytls.CertificateLoader modules?
@ -186,6 +183,7 @@ func decodeBase64DERCert(certStr string) (*x509.Certificate, error) {
return x509.ParseCertificate(derBytes)
}
// KeepAlive holds configuration pertaining to HTTP Keep-Alive.
type KeepAlive struct {
Enabled *bool `json:"enabled,omitempty"`
ProbeInterval caddy.Duration `json:"probe_interval,omitempty"`
@ -200,7 +198,6 @@ var (
KeepAlive: 30 * time.Second,
}
// TODO: does this need to be configured to enable HTTP/2?
defaultTransport = &http.Transport{
DialContext: defaultDialer.DialContext,
TLSHandshakeTimeout: 5 * time.Second,

355
modules/caddyhttp/reverseproxy/reverseproxy.go
View file

@ -18,14 +18,11 @@ import (
"context"
"encoding/json"
"fmt"
"io"
"net"
"net/http"
"net/url"
"regexp"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/caddyserver/caddy/v2"
@ -37,14 +34,14 @@ func init() {
caddy.RegisterModule(Handler{})
}
// Handler implements a highly configurable and production-ready reverse proxy.
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"`
Upstreams UpstreamPool `json:"upstreams,omitempty"`
FlushInterval caddy.Duration `json:"flush_interval,omitempty"`
// UpstreamProvider UpstreamProvider `json:"-"` // TODO:
Transport http.RoundTripper `json:"-"`
}
@ -56,6 +53,7 @@ func (Handler) CaddyModule() caddy.ModuleInfo {
}
}
// Provision ensures that h is set up properly before use.
func (h *Handler) Provision(ctx caddy.Context) error {
if h.TransportRaw != nil {
val, err := ctx.LoadModuleInline("protocol", "http.handlers.reverse_proxy.transport", h.TransportRaw)
@ -236,34 +234,10 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyht
// 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 {
req.Body = nil // Issue golang/go#16036: nil Body for http.Transport retries
}
// TODO: is this needed?
// req.Header = cloneHeader(req.Header)
req.Close = false
// if User-Agent is not set by client, then explicitly
@ -315,10 +289,12 @@ func (h Handler) prepareRequest(req *http.Request) error {
return nil
}
// TODO:
// this code is the entry point to what was borrowed from the net/http/httputil package in the standard library.
// reverseProxy performs a round-trip to the given backend and processes the response with the client.
// (This method is mostly the beginning of what was borrowed from the net/http/httputil package in the
// Go standard library which was used as the foundation.)
func (h *Handler) reverseProxy(rw http.ResponseWriter, req *http.Request, upstream *Upstream) error {
// TODO: count this active request
upstream.Host.CountRequest(1)
defer upstream.Host.CountRequest(-1)
// point the request to this upstream
h.directRequest(req, upstream)
@ -448,202 +424,6 @@ func (h Handler) directRequest(req *http.Request, upstream *Upstream) {
}
}
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 (h Handler) flushInterval(req *http.Request, res *http.Response) time.Duration {
resCT := res.Header.Get("Content-Type")
// For Server-Sent Events responses, flush immediately.
// The MIME type is defined in https://www.w3.org/TR/eventsource/#text-event-stream
if resCT == "text/event-stream" {
return -1 // negative means immediately
}
// TODO: more specific cases? e.g. res.ContentLength == -1?
// return h.FlushInterval
return 0
}
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{
dst: wf,
latency: flushInterval,
}
defer mlw.stop()
dst = mlw
}
}
// 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 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 (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
}
}
}
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
@ -714,6 +494,7 @@ func removeConnectionHeaders(h http.Header) {
}
}
// LoadBalancing has parameters related to load balancing.
type LoadBalancing struct {
SelectionPolicyRaw json.RawMessage `json:"selection_policy,omitempty"`
TryDuration caddy.Duration `json:"try_duration,omitempty"`
@ -722,8 +503,9 @@ type LoadBalancing struct {
SelectionPolicy Selector `json:"-"`
}
// Selector selects an available upstream from the pool.
type Selector interface {
Select(HostPool, *http.Request) *Upstream
Select(UpstreamPool, *http.Request) *Upstream
}
// Hop-by-hop headers. These are removed when sent to the backend.
@ -743,117 +525,6 @@ var hopHeaders = []string{
"Upgrade",
}
// Host represents a remote host which can be proxied to.
// Its methods must be safe for concurrent use.
type Host interface {
// NumRequests returns the numnber of requests
// currently in process with the host.
NumRequests() int
// Fails returns the count of recent failures.
Fails() int
// Unhealthy returns true if the backend is unhealthy.
Unhealthy() bool
// CountRequest counts the given number of requests
// as currently in process with the host. The count
// should not go below 0.
CountRequest(int) error
// CountFail counts the given number of failures
// with the host. The count should not go below 0.
CountFail(int) error
// SetHealthy marks the host as either healthy (true)
// or unhealthy (false). If the given status is the
// same, this should be a no-op. It returns true if
// the given status was different, false otherwise.
SetHealthy(bool) (bool, 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
}
func (uh *upstreamHost) SetHealthy(healthy bool) (bool, error) {
var unhealthy, compare int32 = 1, 0
if healthy {
unhealthy, compare = 0, 1
}
swapped := atomic.CompareAndSwapInt32(&uh.unhealthy, compare, unhealthy)
return swapped, 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 {
}
// TODO: see if we can use this
// var bufPool = sync.Pool{
// New: func() interface{} {
@ -863,7 +534,7 @@ type UpstreamProvider interface {
// Interface guards
var (
_ caddyhttp.MiddlewareHandler = (*Handler)(nil)
_ caddy.Provisioner = (*Handler)(nil)
_ caddy.CleanerUpper = (*Handler)(nil)
_ caddyhttp.MiddlewareHandler = (*Handler)(nil)
)

18
modules/caddyhttp/reverseproxy/selectionpolicies.go
View file

@ -52,7 +52,7 @@ func (RandomSelection) CaddyModule() caddy.ModuleInfo {
}
// Select returns an available host, if any.
func (r RandomSelection) Select(pool HostPool, request *http.Request) *Upstream {
func (r RandomSelection) Select(pool UpstreamPool, request *http.Request) *Upstream {
// use reservoir sampling because the number of available
// hosts isn't known: https://en.wikipedia.org/wiki/Reservoir_sampling
var randomHost *Upstream
@ -87,6 +87,7 @@ func (RandomChoiceSelection) CaddyModule() caddy.ModuleInfo {
}
}
// Provision sets up r.
func (r *RandomChoiceSelection) Provision(ctx caddy.Context) error {
if r.Choose == 0 {
r.Choose = 2
@ -94,6 +95,7 @@ func (r *RandomChoiceSelection) Provision(ctx caddy.Context) error {
return nil
}
// Validate ensures that r's configuration is valid.
func (r RandomChoiceSelection) Validate() error {
if r.Choose < 2 {
return fmt.Errorf("choose must be at least 2")
@ -102,7 +104,7 @@ func (r RandomChoiceSelection) Validate() error {
}
// Select returns an available host, if any.
func (r RandomChoiceSelection) Select(pool HostPool, _ *http.Request) *Upstream {
func (r RandomChoiceSelection) Select(pool UpstreamPool, _ *http.Request) *Upstream {
k := r.Choose
if k > len(pool) {
k = len(pool)
@ -142,7 +144,7 @@ func (LeastConnSelection) CaddyModule() caddy.ModuleInfo {
// Select selects the up host with the least number of connections in the
// pool. If more than one host has the same least number of connections,
// one of the hosts is chosen at random.
func (LeastConnSelection) Select(pool HostPool, _ *http.Request) *Upstream {
func (LeastConnSelection) Select(pool UpstreamPool, _ *http.Request) *Upstream {
var bestHost *Upstream
var count int
var leastReqs int
@ -185,7 +187,7 @@ func (RoundRobinSelection) CaddyModule() caddy.ModuleInfo {
}
// Select returns an available host, if any.
func (r *RoundRobinSelection) Select(pool HostPool, _ *http.Request) *Upstream {
func (r *RoundRobinSelection) Select(pool UpstreamPool, _ *http.Request) *Upstream {
n := uint32(len(pool))
if n == 0 {
return nil
@ -213,7 +215,7 @@ func (FirstSelection) CaddyModule() caddy.ModuleInfo {
}
// Select returns an available host, if any.
func (FirstSelection) Select(pool HostPool, _ *http.Request) *Upstream {
func (FirstSelection) Select(pool UpstreamPool, _ *http.Request) *Upstream {
for _, host := range pool {
if host.Available() {
return host
@ -235,7 +237,7 @@ func (IPHashSelection) CaddyModule() caddy.ModuleInfo {
}
// Select returns an available host, if any.
func (IPHashSelection) Select(pool HostPool, req *http.Request) *Upstream {
func (IPHashSelection) Select(pool UpstreamPool, req *http.Request) *Upstream {
clientIP, _, err := net.SplitHostPort(req.RemoteAddr)
if err != nil {
clientIP = req.RemoteAddr
@ -256,7 +258,7 @@ func (URIHashSelection) CaddyModule() caddy.ModuleInfo {
}
// Select returns an available host, if any.
func (URIHashSelection) Select(pool HostPool, req *http.Request) *Upstream {
func (URIHashSelection) Select(pool UpstreamPool, req *http.Request) *Upstream {
return hostByHashing(pool, req.RequestURI)
}
@ -275,7 +277,7 @@ func (HeaderHashSelection) CaddyModule() caddy.ModuleInfo {
}
// Select returns an available host, if any.
func (s HeaderHashSelection) Select(pool HostPool, req *http.Request) *Upstream {
func (s HeaderHashSelection) Select(pool UpstreamPool, req *http.Request) *Upstream {
if s.Field == "" {
return nil
}

223
modules/caddyhttp/reverseproxy/streaming.go Normal file
View file

@ -0,0 +1,223 @@
// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Most of the code in this file was initially borrowed from the Go
// standard library, which has this copyright notice:
// Copyright 2011 The Go Authors.
package reverseproxy
import (
"context"
"io"
"net/http"
"sync"
"time"
)
func (h Handler) handleUpgradeResponse(rw http.ResponseWriter, req *http.Request, res *http.Response) {
reqUpType := upgradeType(req.Header)
resUpType := upgradeType(res.Header)
if reqUpType != resUpType {
// TODO: figure out our own error handling
// 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 (h Handler) flushInterval(req *http.Request, res *http.Response) time.Duration {
resCT := res.Header.Get("Content-Type")
// For Server-Sent Events responses, flush immediately.
// The MIME type is defined in https://www.w3.org/TR/eventsource/#text-event-stream
if resCT == "text/event-stream" {
return -1 // negative means immediately
}
// TODO: more specific cases? e.g. res.ContentLength == -1? (this TODO is from the std lib)
return time.Duration(h.FlushInterval)
}
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{
dst: wf,
latency: flushInterval,
}
defer mlw.stop()
dst = mlw
}
}
// 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 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 (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
}
}
}
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
}