/*
Copyright 2016 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package system

import (
	"strings"
)

// IsMasterNode returns true if given node is a registered master.
// TODO: find a better way of figuring out if given node is a registered master.
func IsMasterNode(nodeName string) bool {
	// We are trying to capture "master(-...)?$" regexp.
	// However, using regexp.MatchString() results even in more than 35%
	// of all space allocations in ControllerManager spent in this function.
	// That's why we are trying to be a bit smarter.
	if strings.HasSuffix(nodeName, "master") {
		return true
	}
	if len(nodeName) >= 10 {
		return strings.HasSuffix(nodeName[:len(nodeName)-3], "master-")
	}
	return false
}
