Notify slack before draining a node

Fixes #12

cmd/kured/main.go

@@ -173,6 +173,13 @@ func release(lock *daemonsetlock.DaemonSetLock) {
 
 func drain(nodeID string) {
 	log.Infof("Draining node %s", nodeID)
+
+	if slackHookURL != "" {
+		if err := slack.NotifyDrain(slackHookURL, slackUsername, nodeID); err != nil {
+			log.Warnf("Error notifying slack: %v", err)
+		}
+	}
+
 	drainCmd := newCommand("/usr/bin/kubectl", "drain",
 		"--ignore-daemonsets", "--delete-local-data", "--force", nodeID)
 

pkg/notifications/slack/slack.go

@@ -17,9 +17,9 @@ type body struct {
 	Username string `json:"username,omitempty"`
 }
 
-func NotifyReboot(hookURL, username, nodeID string) error {
+func notify(hookURL, username, message string) error {
 	msg := body{
-		Text:     fmt.Sprintf("Rebooting node %s", nodeID),
+		Text:     message,
 		Username: username,
 	}
 
@@ -40,3 +40,11 @@ func NotifyReboot(hookURL, username, nodeID string) error {
 
 	return nil
 }
+
+func NotifyDrain(hookURL, username, nodeID string) error {
+	return notify(hookURL, username, fmt.Sprintf("Draining node %s", nodeID))
+}
+
+func NotifyReboot(hookURL, username, nodeID string) error {
+	return notify(hookURL, username, fmt.Sprintf("Rebooting node %s", nodeID))
+}