Exemple #1
0
// Problems provides list of instances with known problems
func (this *HttpAPI) Agent(params martini.Params, r render.Render, req *http.Request) {
	if !config.Config.ServeAgentsHttp {
		r.JSON(200, &APIResponse{Code: ERROR, Message: "Agents not served"})
		return
	}

	agent, err := agent.GetAgent(params["host"])

	if err != nil {
		r.JSON(200, &APIResponse{Code: ERROR, Message: fmt.Sprintf("%+v", err)})
		return
	}

	r.JSON(200, agent)
}
// DiscoverInstance will attempt discovering an instance (unless it is already up to date) and will
// list down its master and slaves (if any) for further discovery.
func DiscoverInstance(instanceKey inst.InstanceKey) {
	instanceKey.Formalize()
	if !instanceKey.IsValid() {
		return
	}

	instance, found, err := inst.ReadInstance(&instanceKey)

	if found && instance.IsUpToDate && instance.IsLastCheckValid {
		// we've already discovered this one. Skip!
		goto Cleanup
	}
	// First we've ever heard of this instance. Continue investigation:
	instance, err = inst.ReadTopologyInstance(&instanceKey)
	// panic can occur (IO stuff). Therefore it may happen
	// that instance is nil. Check it.
	if err != nil || instance == nil {
		log.Warningf("instance is nil in DiscoverInstance. key=%+v, error=%+v", instanceKey, err)
		goto Cleanup
	}

	fmt.Printf("host: %+v, master: %+v\n", instance.Key, instance.MasterKey)

	// Investigate slaves:
	for _, slaveKey := range instance.SlaveHosts.GetInstanceKeys() {
		discoveryInstanceKeys <- slaveKey
	}
	// Investigate master:
	discoveryInstanceKeys <- instance.MasterKey

Cleanup:
}

// Start discovery begins a one time asynchronuous discovery process for the given
// instance and all of its topology connected instances.
// That is, the instance will be investigated for master and slaves, and the routines will follow on
// each and every such found master/slave.
// In essense, assuming all slaves in a replication topology are running, and given a single instance
// in such topology, this function will detect the entire topology.
func StartDiscovery(instanceKey inst.InstanceKey) {
	log.Infof("Starting discovery at %+v", instanceKey)
	pendingTokens := make(chan bool, maxConcurrency)
	completedTokens := make(chan bool, maxConcurrency)

	AccountedDiscoverInstance(instanceKey, pendingTokens, completedTokens)
	go handleDiscoveryRequests(pendingTokens, completedTokens)

	// Block until all are complete
	for {
		select {
		case <-pendingTokens:
			<-completedTokens
		default:
			inst.AuditOperation("start-discovery", &instanceKey, "")
			return
		}
	}
}

// ContinuousDiscovery starts an asynchronuous infinite discovery process where instances are
// periodically investigated and their status captured, and long since unseen instances are
// purged and forgotten.
func ContinuousDiscovery() {
	log.Infof("Starting continuous discovery")
	go handleDiscoveryRequests(nil, nil)
	tick := time.Tick(time.Duration(config.Config.DiscoveryPollSeconds) * time.Second)
	forgetUnseenTick := time.Tick(time.Hour)
	for _ = range tick {
		instanceKeys, _ := inst.ReadOutdatedInstanceKeys()
		log.Debugf("outdated keys: %+v", instanceKeys)
		for _, instanceKey := range instanceKeys {
			discoveryInstanceKeys <- instanceKey
		}
		// See if we should also forget instances (lower frequency)
		select {
		case <-forgetUnseenTick:
			inst.ForgetLongUnseenInstances()
		default:
		}
	}
}

func pollAgent(hostname string) error {
	polledAgent, err := agent.GetAgent(hostname)
	agent.UpdateAgentLastChecked(hostname)

	if err != nil {
		return log.Errore(err)
	}

	err = agent.UpdateAgentInfo(hostname, polledAgent)
	if err != nil {
		return log.Errore(err)
	}

	return nil
}

// ContinuousAgentsPoll starts an asynchronuous infinite process where agents are
// periodically investigated and their status captured, and long since unseen agents are
// purged and forgotten.
func ContinuousAgentsPoll() {
	log.Infof("Starting continuous agents poll")

	go discoverSeededAgents()

	tick := time.Tick(time.Duration(config.Config.DiscoveryPollSeconds) * time.Second)
	forgetUnseenTick := time.Tick(time.Hour)
	for _ = range tick {
		agentsHosts, _ := agent.ReadOutdatedAgentsHosts()
		log.Debugf("outdated agents hosts: %+v", agentsHosts)
		for _, hostname := range agentsHosts {
			go pollAgent(hostname)
		}
		// See if we should also forget agents (lower frequency)
		select {
		case <-forgetUnseenTick:
			agent.ForgetLongUnseenAgents()
			agent.FailStaleSeeds()
		default:
		}
	}
}

func discoverSeededAgents() {
	for seededAgent := range agent.SeededAgents {
		instanceKey := inst.InstanceKey{Hostname: seededAgent.Hostname, Port: int(seededAgent.MySQLPort)}
		go StartDiscovery(instanceKey)
	}
}