element/events.go
Evan Hazlett 752f9b0d09
initial commit
Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>
2018-06-04 12:40:04 -04:00

60 lines
1.5 KiB
Go

package element
import (
"github.com/hashicorp/memberlist"
)
// NodeEventType is the type of node event
type NodeEventType string
const (
// NodeJoin is the event fired upon a node joining the cluster
NodeJoin NodeEventType = "join"
// NodeLeave is the event fired upon a node leaving the cluster
NodeLeave NodeEventType = "leave"
// NodeUpdate is the event fired upon a node updating in the cluster
NodeUpdate NodeEventType = "update"
)
// NodeEvent stores the event type and node information
type NodeEvent struct {
// EventType is the type of event fired
EventType NodeEventType
// Node is the internal cluster node
Node *memberlist.Node
}
// EventHandler is used for event handling
type EventHandler struct {
ch chan *NodeEvent
}
// NewEventHandler returns an EventHandler that is used to perform actions for the specified event
func NewEventHandler(ch chan *NodeEvent) *EventHandler {
return &EventHandler{
ch: ch,
}
}
// NotifyJoin notifies when a node joins the cluster
func (h *EventHandler) NotifyJoin(n *memberlist.Node) {
go h.notify(NodeJoin, n)
}
// NotifyLeave notifies when a node leaves the cluster
func (h *EventHandler) NotifyLeave(n *memberlist.Node) {
go h.notify(NodeLeave, n)
}
// NotifyUpdate notifies when a node is updated in the cluster
func (h *EventHandler) NotifyUpdate(n *memberlist.Node) {
go h.notify(NodeUpdate, n)
}
func (h *EventHandler) notify(t NodeEventType, n *memberlist.Node) {
// TODO: use context WithTimeout to enable cancel
h.ch <- &NodeEvent{
EventType: t,
Node: n,
}
}