| /* |
| Copyright 2015 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 leaderelection |
| |
| import ( |
| "net/http" |
| "sync" |
| "time" |
| ) |
| |
| // HealthzAdaptor associates the /healthz endpoint with the LeaderElection object. |
| // It helps deal with the /healthz endpoint being set up prior to the LeaderElection. |
| // This contains the code needed to act as an adaptor between the leader |
| // election code the health check code. It allows us to provide health |
| // status about the leader election. Most specifically about if the leader |
| // has failed to renew without exiting the process. In that case we should |
| // report not healthy and rely on the kubelet to take down the process. |
| type HealthzAdaptor struct { |
| pointerLock sync.Mutex |
| le *LeaderElector |
| timeout time.Duration |
| } |
| |
| // Name returns the name of the health check we are implementing. |
| func (l *HealthzAdaptor) Name() string { |
| return "leaderElection" |
| } |
| |
| // Check is called by the healthz endpoint handler. |
| // It fails (returns an error) if we own the lease but had not been able to renew it. |
| func (l *HealthzAdaptor) Check(req *http.Request) error { |
| l.pointerLock.Lock() |
| defer l.pointerLock.Unlock() |
| if l.le == nil { |
| return nil |
| } |
| return l.le.Check(l.timeout) |
| } |
| |
| // SetLeaderElection ties a leader election object to a HealthzAdaptor |
| func (l *HealthzAdaptor) SetLeaderElection(le *LeaderElector) { |
| l.pointerLock.Lock() |
| defer l.pointerLock.Unlock() |
| l.le = le |
| } |
| |
| // NewLeaderHealthzAdaptor creates a basic healthz adaptor to monitor a leader election. |
| // timeout determines the time beyond the lease expiry to be allowed for timeout. |
| // checks within the timeout period after the lease expires will still return healthy. |
| func NewLeaderHealthzAdaptor(timeout time.Duration) *HealthzAdaptor { |
| result := &HealthzAdaptor{ |
| timeout: timeout, |
| } |
| return result |
| } |