packet-manager: sort incoming request ID queue
Incoming queue is not guaranteed to contain request IDs in ascending
order. Such state may be achieved by using a single sftp.Client
connection from multiple goroutines. Sort incoming queue to avoid
livelock due to different request/response order, like this:
2017/03/27 18:29:07 incoming: [55 56 54 57 58]
2017/03/27 18:29:07 outgoing: [54 55 56 57 58]
For single-threaded clients request/response order will remain intact
and nothing should break.
Signed-off-by: Pavel Borzenkov <pavel.borzenkov@gmail.com>
diff --git a/packet-manager.go b/packet-manager.go
index 7969d37..ded3a8f 100644
--- a/packet-manager.go
+++ b/packet-manager.go
@@ -14,7 +14,7 @@
requests chan requestPacket
responses chan responsePacket
fini chan struct{}
- incoming []uint32
+ incoming requestPacketIDs
outgoing responsePackets
sender packetSender // connection object
}
@@ -55,6 +55,9 @@
case pkt := <-s.requests:
debug("incoming id: %v", pkt.id())
s.incoming = append(s.incoming, pkt.id())
+ if len(s.incoming) > 1 {
+ s.incoming.Sort()
+ }
case pkt := <-s.responses:
debug("outgoing pkt: %v", pkt.id())
s.outgoing = append(s.outgoing, pkt)
diff --git a/packet-manager_go1.8.go b/packet-manager_go1.8.go
index c784adc..ccae8c1 100644
--- a/packet-manager_go1.8.go
+++ b/packet-manager_go1.8.go
@@ -11,3 +11,11 @@
return r[i].id() < r[j].id()
})
}
+
+type requestPacketIDs []uint32
+
+func (r requestPacketIDs) Sort() {
+ sort.Slice(r, func(i, j int) bool {
+ return r[i] < r[j]
+ })
+}
diff --git a/packet-manager_legacy.go b/packet-manager_legacy.go
index c54502e..97f0ff0 100644
--- a/packet-manager_legacy.go
+++ b/packet-manager_legacy.go
@@ -4,10 +4,18 @@
import "sort"
-// for sorting/ordering incoming/outgoing
+// for sorting/ordering outgoing
type responsePackets []responsePacket
func (r responsePackets) Len() int { return len(r) }
func (r responsePackets) Swap(i, j int) { r[i], r[j] = r[j], r[i] }
func (r responsePackets) Less(i, j int) bool { return r[i].id() < r[j].id() }
func (r responsePackets) Sort() { sort.Sort(r) }
+
+// for sorting/ordering incoming
+type requestPacketIDs []uint32
+
+func (r requestPacketIDs) Len() int { return len(r) }
+func (r requestPacketIDs) Swap(i, j int) { r[i], r[j] = r[j], r[i] }
+func (r requestPacketIDs) Less(i, j int) bool { return r[i] < r[j] }
+func (r requestPacketIDs) Sort() { sort.Sort(r) }
