3b4ba9d1fb
* Upgrade raft library * Update vendor * Update physical/raft/snapshot_test.go Co-authored-by: Calvin Leung Huang <cleung2010@gmail.com> * Update physical/raft/snapshot_test.go Co-authored-by: Calvin Leung Huang <cleung2010@gmail.com>
153 lines
3.3 KiB
Go
153 lines
3.3 KiB
Go
package raft
|
|
|
|
import (
|
|
"bytes"
|
|
crand "crypto/rand"
|
|
"fmt"
|
|
"math"
|
|
"math/big"
|
|
"math/rand"
|
|
"time"
|
|
|
|
"github.com/hashicorp/go-msgpack/codec"
|
|
)
|
|
|
|
func init() {
|
|
// Ensure we use a high-entropy seed for the pseudo-random generator
|
|
rand.Seed(newSeed())
|
|
}
|
|
|
|
// returns an int64 from a crypto random source
|
|
// can be used to seed a source for a math/rand.
|
|
func newSeed() int64 {
|
|
r, err := crand.Int(crand.Reader, big.NewInt(math.MaxInt64))
|
|
if err != nil {
|
|
panic(fmt.Errorf("failed to read random bytes: %v", err))
|
|
}
|
|
return r.Int64()
|
|
}
|
|
|
|
// randomTimeout returns a value that is between the minVal and 2x minVal.
|
|
func randomTimeout(minVal time.Duration) <-chan time.Time {
|
|
if minVal == 0 {
|
|
return nil
|
|
}
|
|
extra := (time.Duration(rand.Int63()) % minVal)
|
|
return time.After(minVal + extra)
|
|
}
|
|
|
|
// min returns the minimum.
|
|
func min(a, b uint64) uint64 {
|
|
if a <= b {
|
|
return a
|
|
}
|
|
return b
|
|
}
|
|
|
|
// max returns the maximum.
|
|
func max(a, b uint64) uint64 {
|
|
if a >= b {
|
|
return a
|
|
}
|
|
return b
|
|
}
|
|
|
|
// generateUUID is used to generate a random UUID.
|
|
func generateUUID() string {
|
|
buf := make([]byte, 16)
|
|
if _, err := crand.Read(buf); err != nil {
|
|
panic(fmt.Errorf("failed to read random bytes: %v", err))
|
|
}
|
|
|
|
return fmt.Sprintf("%08x-%04x-%04x-%04x-%12x",
|
|
buf[0:4],
|
|
buf[4:6],
|
|
buf[6:8],
|
|
buf[8:10],
|
|
buf[10:16])
|
|
}
|
|
|
|
// asyncNotifyCh is used to do an async channel send
|
|
// to a single channel without blocking.
|
|
func asyncNotifyCh(ch chan struct{}) {
|
|
select {
|
|
case ch <- struct{}{}:
|
|
default:
|
|
}
|
|
}
|
|
|
|
// drainNotifyCh empties out a single-item notification channel without
|
|
// blocking, and returns whether it received anything.
|
|
func drainNotifyCh(ch chan struct{}) bool {
|
|
select {
|
|
case <-ch:
|
|
return true
|
|
default:
|
|
return false
|
|
}
|
|
}
|
|
|
|
// asyncNotifyBool is used to do an async notification
|
|
// on a bool channel.
|
|
func asyncNotifyBool(ch chan bool, v bool) {
|
|
select {
|
|
case ch <- v:
|
|
default:
|
|
}
|
|
}
|
|
|
|
// overrideNotifyBool is used to notify on a bool channel
|
|
// but override existing value if value is present.
|
|
// ch must be 1-item buffered channel.
|
|
//
|
|
// This method does not support multiple concurrent calls.
|
|
func overrideNotifyBool(ch chan bool, v bool) {
|
|
select {
|
|
case ch <- v:
|
|
// value sent, all done
|
|
case <-ch:
|
|
// channel had an old value
|
|
select {
|
|
case ch <- v:
|
|
default:
|
|
panic("race: channel was sent concurrently")
|
|
}
|
|
}
|
|
}
|
|
|
|
// Decode reverses the encode operation on a byte slice input.
|
|
func decodeMsgPack(buf []byte, out interface{}) error {
|
|
r := bytes.NewBuffer(buf)
|
|
hd := codec.MsgpackHandle{}
|
|
dec := codec.NewDecoder(r, &hd)
|
|
return dec.Decode(out)
|
|
}
|
|
|
|
// Encode writes an encoded object to a new bytes buffer.
|
|
func encodeMsgPack(in interface{}) (*bytes.Buffer, error) {
|
|
buf := bytes.NewBuffer(nil)
|
|
hd := codec.MsgpackHandle{}
|
|
enc := codec.NewEncoder(buf, &hd)
|
|
err := enc.Encode(in)
|
|
return buf, err
|
|
}
|
|
|
|
// backoff is used to compute an exponential backoff
|
|
// duration. Base time is scaled by the current round,
|
|
// up to some maximum scale factor.
|
|
func backoff(base time.Duration, round, limit uint64) time.Duration {
|
|
power := min(round, limit)
|
|
for power > 2 {
|
|
base *= 2
|
|
power--
|
|
}
|
|
return base
|
|
}
|
|
|
|
// Needed for sorting []uint64, used to determine commitment
|
|
type uint64Slice []uint64
|
|
|
|
func (p uint64Slice) Len() int { return len(p) }
|
|
func (p uint64Slice) Less(i, j int) bool { return p[i] < p[j] }
|
|
func (p uint64Slice) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
|