+// Copyright (C) The Arvados Authors. All rights reserved.
+//
+// SPDX-License-Identifier: AGPL-3.0
+
package main
import (
+ "context"
"io"
- "net/http"
+ "sync"
"time"
+
+ "git.curoverse.com/arvados.git/sdk/go/arvados"
+ "git.curoverse.com/arvados.git/sdk/go/stats"
)
-type handler interface {
- Handle(wsConn, <-chan *event)
+type handler struct {
+ Client arvados.Client
+ PingTimeout time.Duration
+ QueueSize int
+
+ mtx sync.Mutex
+ lastDelay map[chan interface{}]stats.Duration
+ setupOnce sync.Once
+}
+
+type handlerStats struct {
+ QueueDelayNs time.Duration
+ WriteDelayNs time.Duration
+ EventBytes uint64
+ EventCount uint64
+}
+
+func (h *handler) Handle(ws wsConn, eventSource eventSource, newSession func(wsConn, chan<- interface{}) (session, error)) (hStats handlerStats) {
+ h.setupOnce.Do(h.setup)
+
+ ctx, cancel := context.WithCancel(ws.Request().Context())
+ defer cancel()
+ log := logger(ctx)
+
+ incoming := eventSource.NewSink()
+ defer incoming.Stop()
+
+ queue := make(chan interface{}, h.QueueSize)
+ h.mtx.Lock()
+ h.lastDelay[queue] = 0
+ h.mtx.Unlock()
+ defer func() {
+ h.mtx.Lock()
+ delete(h.lastDelay, queue)
+ h.mtx.Unlock()
+ }()
+
+ sess, err := newSession(ws, queue)
+ if err != nil {
+ log.WithError(err).Error("newSession failed")
+ return
+ }
+
+ // Receive websocket frames from the client and pass them to
+ // sess.Receive().
+ go func() {
+ buf := make([]byte, 2<<20)
+ for {
+ select {
+ case <-ctx.Done():
+ return
+ default:
+ }
+ ws.SetReadDeadline(time.Now().Add(24 * 365 * time.Hour))
+ n, err := ws.Read(buf)
+ buf := buf[:n]
+ log.WithField("frame", string(buf[:n])).Debug("received frame")
+ if err == nil && n == cap(buf) {
+ err = errFrameTooBig
+ }
+ if err != nil {
+ if err != io.EOF {
+ log.WithError(err).Info("read error")
+ }
+ cancel()
+ return
+ }
+ err = sess.Receive(buf)
+ if err != nil {
+ log.WithError(err).Error("sess.Receive() failed")
+ cancel()
+ return
+ }
+ }
+ }()
+
+ // Take items from the outgoing queue, serialize them using
+ // sess.EventMessage() as needed, and send them to the client
+ // as websocket frames.
+ go func() {
+ for {
+ var ok bool
+ var data interface{}
+ select {
+ case <-ctx.Done():
+ return
+ case data, ok = <-queue:
+ if !ok {
+ return
+ }
+ }
+ var e *event
+ var buf []byte
+ var err error
+ log := log
+
+ switch data := data.(type) {
+ case []byte:
+ buf = data
+ case *event:
+ e = data
+ log = log.WithField("serial", e.Serial)
+ buf, err = sess.EventMessage(e)
+ if err != nil {
+ log.WithError(err).Error("EventMessage failed")
+ cancel()
+ break
+ } else if len(buf) == 0 {
+ log.Debug("skip")
+ continue
+ }
+ default:
+ log.WithField("data", data).Error("bad object in client queue")
+ continue
+ }
+
+ log.WithField("frame", string(buf)).Debug("send event")
+ ws.SetWriteDeadline(time.Now().Add(h.PingTimeout))
+ t0 := time.Now()
+ _, err = ws.Write(buf)
+ if err != nil {
+ log.WithError(err).Error("write failed")
+ cancel()
+ break
+ }
+ log.Debug("sent")
+
+ if e != nil {
+ hStats.QueueDelayNs += t0.Sub(e.Ready)
+ h.mtx.Lock()
+ h.lastDelay[queue] = stats.Duration(time.Since(e.Ready))
+ h.mtx.Unlock()
+ }
+ hStats.WriteDelayNs += time.Since(t0)
+ hStats.EventBytes += uint64(len(buf))
+ hStats.EventCount++
+ }
+ }()
+
+ // Filter incoming events against the current subscription
+ // list, and forward matching events to the outgoing message
+ // queue. Close the queue and return when the request context
+ // is done/cancelled or the incoming event stream ends. Shut
+ // down the handler if the outgoing queue fills up.
+ go func() {
+ ticker := time.NewTicker(h.PingTimeout)
+ defer ticker.Stop()
+
+ for {
+ select {
+ case <-ctx.Done():
+ return
+ case <-ticker.C:
+ // If the outgoing queue is empty,
+ // send an empty message. This can
+ // help detect a disconnected network
+ // socket, and prevent an idle socket
+ // from being closed.
+ if len(queue) == 0 {
+ select {
+ case queue <- []byte(`{}`):
+ default:
+ }
+ }
+ continue
+ case e, ok := <-incoming.Channel():
+ if !ok {
+ cancel()
+ return
+ }
+ if !sess.Filter(e) {
+ continue
+ }
+ select {
+ case queue <- e:
+ default:
+ log.WithError(errQueueFull).Error("terminate")
+ cancel()
+ return
+ }
+ }
+ }
+ }()
+
+ <-ctx.Done()
+ return
+}
+
+func (h *handler) DebugStatus() interface{} {
+ h.mtx.Lock()
+ defer h.mtx.Unlock()
+
+ var s struct {
+ QueueCount int
+ QueueMin int
+ QueueMax int
+ QueueTotal uint64
+ QueueDelayMin stats.Duration
+ QueueDelayMax stats.Duration
+ }
+ for q, lastDelay := range h.lastDelay {
+ s.QueueCount++
+ n := len(q)
+ s.QueueTotal += uint64(n)
+ if s.QueueMax < n {
+ s.QueueMax = n
+ }
+ if s.QueueMin > n || s.QueueCount == 1 {
+ s.QueueMin = n
+ }
+ if (s.QueueDelayMin > lastDelay || s.QueueDelayMin == 0) && lastDelay > 0 {
+ s.QueueDelayMin = lastDelay
+ }
+ if s.QueueDelayMax < lastDelay {
+ s.QueueDelayMax = lastDelay
+ }
+ }
+ return &s
}
-type wsConn interface {
- io.ReadWriter
- Request() *http.Request
- SetReadDeadline(time.Time) error
- SetWriteDeadline(time.Time) error
+func (h *handler) setup() {
+ h.lastDelay = make(map[chan interface{}]stats.Duration)
}
projects / arvados.git / blobdiff