// Campaign handles leader election. Basically this just acquires a lock on the LeadershipKey and whoever gets the lock
// is the leader. A re-election occurs when there are changes in the LeadershipKey.
func (c *Candidate) campaign() {
c.retrieveNode()
c.retrieveSession()
consul := c.consulClient()
logrus.Debugf("%s is running for election with session %s.", c.node, c.session)
kvpair := &consulapi.KVPair{
Key: c.LeadershipKey,
Value: []byte(c.node),
Session: c.session,
}
acquired, _, err := consul.KV().Acquire(kvpair, nil)
if err != nil {
logrus.Errorln("Failed to run Consul KV Acquire:", err)
}
if acquired {
logrus.Infof("%s has become the leader.", c.node)
}
kv, _, _ := consul.KV().Get(c.LeadershipKey, nil)
if kv != nil && kv.Session != "" {
logrus.Debugf("%s is the current leader.", string(kv.Value))
logrus.Debugf("%s is waiting for changes in '%s'.", c.node, c.LeadershipKey)
latestIndex := kv.ModifyIndex
options := &consulapi.QueryOptions{
WaitIndex: latestIndex,
}
consul.KV().Get(c.LeadershipKey, options)
}
time.Sleep(15 * time.Second)
c.campaign()
}
func (beary *BearyNotifier) postToBeary() bool {
data, err := json.Marshal(beary)
if err != nil {
log.Println("Unable to marshal beary payload:", err)
return false
}
log.Debugf("struct = %+v, json = %s", beary, string(data))
b := bytes.NewBuffer(data)
if res, err := http.Post(beary.Url, "application/json", b); err != nil {
log.Println("Unable to send data to beary:", err)
return false
} else {
defer res.Body.Close()
statusCode := res.StatusCode
if statusCode != 200 {
body, _ := ioutil.ReadAll(res.Body)
log.Println("Unable to notify beary:", string(body))
return false
} else {
log.Println("Beary notification sent.")
return true
}
}
}
func (influxdb *InfluxdbNotifier) toBatchPoints(messages Messages, bp client.BatchPoints) {
seriesName := influxdb.SeriesName
for index, message := range messages {
tags := map[string]string{
"node": message.Node,
"service": message.Service,
"status": message.Status,
"serviceId": message.ServiceId,
}
fields := map[string]interface{}{
"checks": message.Check,
"notes": message.Notes,
"output": message.Output,
}
p, err := client.NewPoint(seriesName, tags, fields, message.Timestamp)
if err != nil {
log.Println("Error: ", err.Error())
}
log.Debugf("%s", index)
bp.AddPoint(p)
}
}
// Resign forces the current agent to step down as the leader forcing a re-election. Nothing happens if the agent is not
// the current leader.
func (c *Candidate) Resign() {
if c.IsLeader() {
consul := c.consulClient()
kvpair := &consulapi.KVPair{
Key: c.LeadershipKey,
Value: []byte(c.node),
Session: c.session,
}
success, _, err := consul.KV().Release(kvpair, nil)
if !success || err != nil {
logrus.Warnf("%s was unable to step down as a leader", c.node)
} else {
logrus.Debugf("%s is no longer the leader.", c.node)
}
}
}