Timeout after 10 seconds on address resolution.

niemeyer · niemeyer · commit e15707acad38 · 2014-07-21T01:36:40.000-03:00
Fixes MGO-34, reported by Cailin Nelson.
diff --git a/cluster.go b/cluster.go
@@ -395,11 +395,14 @@ func (cluster *mongoCluster) server(addr string, tcpaddr *net.TCPAddr) *mongoSer
 }
 
 func resolveAddr(addr string) (*net.TCPAddr, error) {
-	tcpaddr, err := net.ResolveTCPAddr("tcp", addr)
+	// This hack allows having a timeout on resolution.
+	conn, err := net.DialTimeout("udp", addr, 10 * time.Second)
 	if err != nil {
-		log("SYNC Failed to resolve ", addr, ": ", err.Error())
-		return nil, err
+		log("SYNC Failed to resolve server address: ", addr)
+		return nil, errors.New("failed to resolve server address: " + addr)
 	}
+	tcpaddr := (*net.TCPAddr)(conn.RemoteAddr().(*net.UDPAddr))
+	conn.Close()
 	if tcpaddr.String() != addr {
 		debug("SYNC Address ", addr, " resolved as ", tcpaddr.String())
 	}

Original file line number	Diff line number	Diff line change
`@@ -395,11 +395,14 @@ func (cluster mongoCluster) server(addr string, tcpaddr net.TCPAddr) *mongoSer`
`395`	`395`	`}`
`396`	`396`
`397`	`397`	`func resolveAddr(addr string) (*net.TCPAddr, error) {`
`398`		`- tcpaddr, err := net.ResolveTCPAddr("tcp", addr)`
	`398`	`+ // This hack allows having a timeout on resolution.`
	`399`	`+ conn, err := net.DialTimeout("udp", addr, 10 * time.Second)`
`399`	`400`	`if err != nil {`
`400`		`- log("SYNC Failed to resolve ", addr, ": ", err.Error())`
`401`		`- return nil, err`
	`401`	`+ log("SYNC Failed to resolve server address: ", addr)`
	`402`	`+ return nil, errors.New("failed to resolve server address: " + addr)`
`402`	`403`	`}`
	`404`	`+ tcpaddr := (net.TCPAddr)(conn.RemoteAddr().(net.UDPAddr))`
	`405`	`+ conn.Close()`
`403`	`406`	`if tcpaddr.String() != addr {`
`404`	`407`	`debug("SYNC Address ", addr, " resolved as ", tcpaddr.String())`
`405`	`408`	`}`