Add KeepAlive Support

This adds support for KeepAlive to queries.
Each query must set KeepAlive to keep the connection open. The
connection will be closed on the first Query without KeepAlive
set.

livestatus.go

@@ -8,10 +8,24 @@ type Livestatus struct {
 	network string
 	address string
 	dialer  func() (net.Conn, error)
+
+	keepalive bool
+	keepConn  net.Conn
+}
+
+// Close any open connection from a KeepAlive
+func (l *Livestatus) Close() error {
+	l.keepalive = false
+	if l.keepConn != nil {
+		l.keepConn = nil
+		return l.keepConn.Close()
+	}
+	return nil
 }
 
 // Query creates a new query instance on a spacific table.
 func (l *Livestatus) Query(table string) *Query {
+	l.keepalive = false
 	return newQuery(table, l)
 }
 

query.go

@@ -26,6 +26,12 @@ func (q *Query) Columns(names ...string) *Query {
 	return q
 }
 
+// KeepAlive keeps the connection open after the query, for re-use
+func (q *Query) KeepAlive() *Query {
+	q.headers = append(q.headers, "KeepAlive: on")
+	return q
+}
+
 // Filter sets a new filter to apply to the query.
 func (q *Query) Filter(rule string) *Query {
 	q.headers = append(q.headers, "Filter: "+rule)
@@ -108,12 +114,25 @@ func (q *Query) WaitTimeout(t time.Duration) *Query {
 func (q *Query) Exec() (*Response, error) {
 	resp := &Response{}
 
-	// Connect to socket
-	conn, err := q.dial()
-	if err != nil {
-		return nil, err
+	var err error
+	var conn net.Conn
+
+	if q.ls.keepConn != nil {
+		conn = q.ls.keepConn
+	} else {
+		// Connect to socket
+		conn, err = q.dial()
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if !q.ls.keepalive {
+		q.ls.keepConn = nil
+		defer conn.Close()
+	} else {
+		q.ls.keepConn = conn
 	}
-	defer conn.Close()
 
 	// Send command data
 	conn.Write([]byte(q.buildCmd()))