docs/cli/join.go

84 lines
2.1 KiB
Go

package cli
import (
"math/rand"
"net"
"strconv"
"time"
log "github.com/Sirupsen/logrus"
"github.com/codegangsta/cli"
"github.com/docker/docker/pkg/discovery"
)
func checkAddrFormat(addr string) bool {
// validate addr is in host:port form. Use net function to handle both IPv4/IPv6 cases.
_, port, err := net.SplitHostPort(addr)
if err != nil {
return false
}
portNum, err := strconv.Atoi(port)
return err == nil && portNum > 0 && portNum <= 65535
}
func join(c *cli.Context) {
dflag := getDiscovery(c)
if dflag == "" {
log.Fatalf("discovery required to join a cluster. See '%s join --help'.", c.App.Name)
}
addr := c.String("advertise")
if addr == "" {
log.Fatal("missing mandatory --advertise flag")
}
if !checkAddrFormat(addr) {
log.Fatal("--advertise should be of the form ip:port or hostname:port")
}
joinDelay, err := time.ParseDuration(c.String("delay"))
if err != nil {
log.Fatalf("invalid --delay: %v", err)
}
if joinDelay < time.Duration(0)*time.Second {
log.Fatalf("--delay should not be a negative number")
}
hb, err := time.ParseDuration(c.String("heartbeat"))
if err != nil {
log.Fatalf("invalid --heartbeat: %v", err)
}
if hb < 1*time.Second {
log.Fatal("--heartbeat should be at least one second")
}
ttl, err := time.ParseDuration(c.String("ttl"))
if err != nil {
log.Fatalf("invalid --ttl: %v", err)
}
if ttl <= hb {
log.Fatal("--ttl must be strictly superior to the heartbeat value")
}
d, err := discovery.New(dflag, hb, ttl, getDiscoveryOpt(c))
if err != nil {
log.Fatal(err)
}
// if joinDelay is 0, no delay will be executed
// if joinDelay is larger than 0,
// add a random delay between 0s and joinDelay at start to avoid synchronized registration
if joinDelay > 0 {
r := rand.New(rand.NewSource(time.Now().UTC().UnixNano()))
delay := time.Duration(r.Int63n(int64(joinDelay)))
log.Infof("Add a random delay %s to avoid synchronized registration", delay)
time.Sleep(delay)
}
for {
log.WithFields(log.Fields{"addr": addr, "discovery": dflag}).Infof("Registering on the discovery service every %s...", hb)
if err := d.Register(addr); err != nil {
log.Error(err)
}
time.Sleep(hb)
}
}