http://stackoverflow.com/questions/32486466/go-best-practices-function-vs-method-with-ambiguous-receiver

probe_worker.go

/*
Copyright 2014 The Kubernetes Authors All rights reserved.

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.
*/

// run periodically probes the container.
func run(pm *probeManager, w *probeWorker) {
	container, ok := <-w.targets
	probeTicker := time.Tick(w.probePeriod)

	// Handle new target container.
newContainer:
	if !ok {
		// No more targets, shutdown the worker.
		if w.probeType == readinessProbe {
			pm.readinessCache.remove(container.ID)
		} else {
			pm.livenessCache.remove(container.ID)
		}
		return
	}

	remainingDelay := time.Now().Unix() - (container.Created + w.spec.InitialDelaySeconds)
	if remainingDelay > 0 {
		if w.probeType == readinessProbe {
			// Readiness probes default to Failure during initial delay.
			pm.reportReadiness(container.ID, Failure)
		}

		select {
		case container, ok = <-targets:
			// Container restarted during initial delay.
			goto newContainer
		case <-time.After(remainingDelay):
			// Carry on.
		}
	}

	for {
		select {
		case container, ok = <-targets:
			// Restart the probe loop with the new target.
			goto newContainer

		case <-probeTicker:
			doProbe(pm, w, container.ID)
		}
	}
}

// doProbe probes the container once and records the result.
func doProbe(pm *probeManager, w *probeWorker, containerID types.UID) {
	status := pm.statusCache.GetPodStatus(w.pod.UID)

	if w.probeType == readinessProbe {
		// TODO: Move error handling out of prober.
		result, _ := pm.prober.probeReadiness(w.pod, status, w.container, containerID)
		pm.readinessCache.set(containerID, result)
	} else { // probeType == livenessProbe
		result, err := pm.prober.probeLiveness(w.pod, status, w.container, containerID)
		// If the liveness probe failed, skip reporting (state unchanged).
		if err == nil {
			prevResult = pm.livenessCache.get(containerID)
			pm.livenessCache.set(containerID, result)
			if result != prevResult {
				// Trigger a (non-blocking) sync if the probe result changed.
				select {
				case pm.syncChan <- struct{}{}:
				default:
				}
			}
		}
	}
}