forked from nsqio/nsq
/
queue.go
114 lines (96 loc) · 2.09 KB
/
queue.go
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package main
import (
"../nsq"
"../util/pqueue"
"bytes"
"log"
)
// BackendQueue represents the behavior for the secondary message
// storage system
type BackendQueue interface {
Put([]byte) error
ReadChan() chan []byte // this is expected to be an *unbuffered* channel
Close() error
Depth() int64
Empty() error
}
type Queue interface {
MemoryChan() chan *nsq.Message
BackendQueue() BackendQueue
InFlight() map[nsq.MessageID]*pqueue.Item
Deferred() map[nsq.MessageID]*pqueue.Item
}
type DummyBackendQueue struct {
readChan chan []byte
}
func NewDummyBackendQueue() BackendQueue {
return &DummyBackendQueue{readChan: make(chan []byte)}
}
func (d *DummyBackendQueue) Put([]byte) error {
return nil
}
func (d *DummyBackendQueue) ReadChan() chan []byte {
return d.readChan
}
func (d *DummyBackendQueue) Close() error {
return nil
}
func (d *DummyBackendQueue) Depth() int64 {
return int64(0)
}
func (d *DummyBackendQueue) Empty() error {
return nil
}
func EmptyQueue(q Queue) error {
for {
select {
case <-q.MemoryChan():
default:
goto disk
}
}
disk:
return q.BackendQueue().Empty()
}
func FlushQueue(q Queue) error {
var msgBuf bytes.Buffer
for {
select {
case msg := <-q.MemoryChan():
err := WriteMessageToBackend(&msgBuf, msg, q)
if err != nil {
log.Printf("ERROR: failed to write message to backend - %s", err.Error())
}
default:
goto finish
}
}
finish:
for _, item := range q.InFlight() {
msg := item.Value.(*inFlightMessage).msg
err := WriteMessageToBackend(&msgBuf, msg, q)
if err != nil {
log.Printf("ERROR: failed to write message to backend - %s", err.Error())
}
}
for _, item := range q.Deferred() {
msg := item.Value.(*nsq.Message)
err := WriteMessageToBackend(&msgBuf, msg, q)
if err != nil {
log.Printf("ERROR: failed to write message to backend - %s", err.Error())
}
}
return nil
}
func WriteMessageToBackend(buf *bytes.Buffer, msg *nsq.Message, q Queue) error {
buf.Reset()
err := msg.Write(buf)
if err != nil {
return err
}
err = q.BackendQueue().Put(buf.Bytes())
if err != nil {
return err
}
return nil
}