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authorMatthew Holt <mholt@users.noreply.github.com>2019-09-03 16:56:09 -0600
committerMatthew Holt <mholt@users.noreply.github.com>2019-09-03 16:56:09 -0600
commit652460e03e11a037d9f86b09b3546c9e42733d2d (patch)
tree9b1042f3fc880f87ca25949618fea45e6960080a
parent4a1e1649bc985e9658d326ed433a101d7d79ae30 (diff)
Some cleanup and godoc
-rw-r--r--modules/caddyhttp/reverseproxy/healthchecks.go12
-rw-r--r--modules/caddyhttp/reverseproxy/hosts.go161
-rw-r--r--modules/caddyhttp/reverseproxy/httptransport.go21
-rw-r--r--modules/caddyhttp/reverseproxy/reverseproxy.go355
-rw-r--r--modules/caddyhttp/reverseproxy/selectionpolicies.go18
-rw-r--r--modules/caddyhttp/reverseproxy/streaming.go223
6 files changed, 428 insertions, 362 deletions
diff --git a/modules/caddyhttp/reverseproxy/healthchecks.go b/modules/caddyhttp/reverseproxy/healthchecks.go
index 96649a4..0b46d04 100644
--- a/modules/caddyhttp/reverseproxy/healthchecks.go
+++ b/modules/caddyhttp/reverseproxy/healthchecks.go
@@ -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)
diff --git a/modules/caddyhttp/reverseproxy/hosts.go b/modules/caddyhttp/reverseproxy/hosts.go
new file mode 100644
index 0000000..5100936
--- /dev/null
+++ b/modules/caddyhttp/reverseproxy/hosts.go
@@ -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()
diff --git a/modules/caddyhttp/reverseproxy/httptransport.go b/modules/caddyhttp/reverseproxy/httptransport.go
index 999a352..d9dc457 100644
--- a/modules/caddyhttp/reverseproxy/httptransport.go
+++ b/modules/caddyhttp/reverseproxy/httptransport.go
@@ -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,
diff --git a/modules/caddyhttp/reverseproxy/reverseproxy.go b/modules/caddyhttp/reverseproxy/reverseproxy.go
index ebf6ac1..ca54741 100644
--- a/modules/caddyhttp/reverseproxy/reverseproxy.go
+++ b/modules/caddyhttp/reverseproxy/reverseproxy.go
@@ -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)
)
diff --git a/modules/caddyhttp/reverseproxy/selectionpolicies.go b/modules/caddyhttp/reverseproxy/selectionpolicies.go
index e0518c9..9680583 100644
--- a/modules/caddyhttp/reverseproxy/selectionpolicies.go
+++ b/modules/caddyhttp/reverseproxy/selectionpolicies.go
@@ -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
}
diff --git a/modules/caddyhttp/reverseproxy/streaming.go b/modules/caddyhttp/reverseproxy/streaming.go
new file mode 100644
index 0000000..a3b711b
--- /dev/null
+++ b/modules/caddyhttp/reverseproxy/streaming.go
@@ -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
+}