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107 lines
2.1 KiB
Go
107 lines
2.1 KiB
Go
package update
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import (
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"crypto/md5"
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"errors"
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"fmt"
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"io"
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"sort"
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"zero/core/hash"
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"zero/core/jsonx"
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"zero/rq/internal"
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)
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var ErrInvalidServerChange = errors.New("not a server change message")
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type (
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weightedKey struct {
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Key string
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Weight int
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}
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Snapshot struct {
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Keys []string
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WeightedKeys []weightedKey
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}
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ServerChange struct {
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Previous Snapshot
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Current Snapshot
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Servers []string
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}
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)
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func (s Snapshot) GetCode() string {
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keys := append([]string(nil), s.Keys...)
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sort.Strings(keys)
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weightedKeys := append([]weightedKey(nil), s.WeightedKeys...)
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sort.SliceStable(weightedKeys, func(i, j int) bool {
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return weightedKeys[i].Key < weightedKeys[j].Key
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})
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digest := md5.New()
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for _, key := range keys {
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io.WriteString(digest, fmt.Sprintf("%s\n", key))
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}
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for _, wkey := range weightedKeys {
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io.WriteString(digest, fmt.Sprintf("%s:%d\n", wkey.Key, wkey.Weight))
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}
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return fmt.Sprintf("%x", digest.Sum(nil))
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}
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func (sc ServerChange) CreateCurrentHash() *hash.ConsistentHash {
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curHash := hash.NewConsistentHash()
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for _, key := range sc.Current.Keys {
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curHash.Add(key)
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}
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for _, wkey := range sc.Current.WeightedKeys {
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curHash.AddWithWeight(wkey.Key, wkey.Weight)
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}
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return curHash
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}
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func (sc ServerChange) CreatePrevHash() *hash.ConsistentHash {
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prevHash := hash.NewConsistentHash()
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for _, key := range sc.Previous.Keys {
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prevHash.Add(key)
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}
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for _, wkey := range sc.Previous.WeightedKeys {
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prevHash.AddWithWeight(wkey.Key, wkey.Weight)
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}
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return prevHash
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}
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func (sc ServerChange) GetCode() string {
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return sc.Current.GetCode()
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}
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func IsServerChange(message string) bool {
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return len(message) > 0 && message[0] == internal.ServerSensitivePrefix
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}
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func (sc ServerChange) Marshal() (string, error) {
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body, err := jsonx.Marshal(sc)
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if err != nil {
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return "", err
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}
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return string(append([]byte{internal.ServerSensitivePrefix}, body...)), nil
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}
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func UnmarshalServerChange(body string) (ServerChange, error) {
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if len(body) == 0 {
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return ServerChange{}, ErrInvalidServerChange
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}
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var change ServerChange
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err := jsonx.UnmarshalFromString(body[1:], &change)
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return change, err
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}
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