util.go

package cluster

import (
	"fmt"
	"os"
	"sort"
	"sync/atomic"
	"time"

	"github.com/Shopify/sarama"
)

/* Claims map */

type Claims map[int32]*sarama.PartitionConsumer

// PartitionIDs returns the associated partition IDs
func (c Claims) PartitionIDs() []int32 {
	ids := make(int32Slice, 0, len(c))
	for id, _ := range c {
		ids = append(ids, id)
	}
	return ids.Sorted()
}

/* GUID generator */

// Global UID config
var cGUID struct {
	hostname string
	pid      int
	inc      uint32
}

// Init GUID configuration
func init() {
	cGUID.hostname, _ = os.Hostname()
	cGUID.pid = os.Getpid()
	cGUID.inc = 0xffffffff
	if cGUID.hostname == "" {
		cGUID.hostname = "localhost"
	}
}

// Create a new GUID
func newGUID(prefix string) string {
	return newGUIDAt(prefix, time.Now())
}

// Create a new GUID for a certain time
func newGUIDAt(prefix string, at time.Time) string {
	inc := atomic.AddUint32(&cGUID.inc, 1)
	uts := at.Unix()
	ins := fmt.Sprintf("%08x", inc)
	return fmt.Sprintf("%s:%s:%08x-%04x-%s-%s", prefix, cGUID.hostname, uts, cGUID.pid, ins[:4], ins[4:])
}

/* Sortable int32Slice */

type int32Slice []int32

func (s int32Slice) Len() int           { return len(s) }
func (s int32Slice) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
func (s int32Slice) Less(i, j int) bool { return s[i] < s[j] }
func (s int32Slice) Sorted() []int32    { sort.Sort(s); return []int32(s) }