Snowflake ID Generator for Twitter: Create and Analyze IDs
Generer og analyser Twitter Snowflake IDs, unikke 64-bit identifikatorer, der bruges i distribuerede systemer. Dette værktøj giver dig mulighed for at oprette nye Snowflake IDs og analysere eksisterende, hvilket giver indsigt i deres tidsstempel, maskin-ID og sekvensnummer komponenter.
Snowflake ID-generator
Snowflake ID-generator
Dokumentation
Snowflake ID Generator
Introduktion
En Snowflake ID er en unik identifikator, der bruges i distribuerede systemer, oprindeligt udviklet af Twitter. Dette værktøj giver dig mulighed for at generere og analysere Snowflake IDs, som er 64-bit heltal sammensat af et tidsstempel, maskin-ID og sekvensnummer.
Hvordan Snowflake IDs fungerer
Snowflake IDs er 64-bit heltal struktureret som følger:
- 41 bits: Tidsstempel (millisekunder siden en brugerdefineret epoch)
- 10 bits: Maskin-ID (5 bits til datacenter-ID, 5 bits til arbejdere-ID)
- 12 bits: Sekvensnummer
Denne struktur muliggør generering af cirka 4.096 unikke IDs pr. millisekund pr. maskine.
Brug af Snowflake ID Generator
- (Valgfrit) Indstil en brugerdefineret epoch (standard er Twitters epoch: 2010-11-04T01:42:54.657Z)
- Indtast et maskin-ID (0-31) og datacenter-ID (0-31)
- Klik på "Generer" for at oprette en ny Snowflake ID
- Den genererede ID og dens komponenter vises
For at analysere en eksisterende Snowflake ID, indtast den i feltet "Parse ID" og klik på "Parse".
Formel
Snowflake ID'en konstrueres ved hjælp af bitvise operationer:
1ID = (timestamp << 22) | (datacenterId << 17) | (workerId << 12) | sequence
2
Hvor:
timestamp
er antallet af millisekunder siden epochdatacenterId
er et 5-bit heltal (0-31)workerId
er et 5-bit heltal (0-31)sequence
er et 12-bit heltal (0-4095)
Beregning
Snowflake ID generatoren udfører følgende trin:
- Få det aktuelle tidsstempel i millisekunder
- Sørg for, at tidsstemplet er større end det sidst brugte tidsstempel (for unikhed)
- Hvis tidsstemplet er det samme som det sidste, skal sekvensnummeret inkrementeres
- Hvis sekvensnummeret løber over (når 4096), skal der ventes på det næste millisekund
- Kombiner komponenterne ved hjælp af bitvise operationer for at skabe den endelige ID
Anvendelsessager
Snowflake IDs er særligt nyttige i:
- Distribuerede systemer: Generere unikke IDs på tværs af flere maskiner uden koordinering
- Højvolumen data: Oprette sorterbare IDs til store datasæt
- Mikrotjenester: Sikre unikke identifikatorer på tværs af forskellige tjenester
- Database sharding: Brug tidsstempel- eller maskin-ID-komponenten til effektiv sharding
Alternativer
Mens Snowflake IDs er kraftfulde, inkluderer andre ID-genereringssystemer:
- UUID (Universally Unique Identifier): Nyttig når distribueret generation er nødvendig uden sortering
- Auto-inkrementerende database IDs: Simpel, men begrænset til enkelt databaseinstanser
- ULID (Universally Unique Lexicographically Sortable Identifier): Ligner Snowflake, men med en anden struktur
Grænsetilfælde og begrænsninger
-
Klokkesynkronisering: Snowflake IDs er afhængige af systemtiden. Hvis klokken bevæger sig bagud på grund af NTP-justeringer eller ændringer i sommertid, kan det forårsage problemer med ID-generering.
-
År 2038-problemet: Det 41-bit tidsstempel vil overflyde i 2079 (forudsat Twitters epoch). Systemer, der bruger Snowflake IDs, bør planlægge for denne eventualitet.
-
Maskin-ID-kollisioner: I store distribuerede systemer kan det være udfordrende at sikre unikke maskin-ID'er og kan kræve yderligere koordinering.
-
Sekvensoverløb: I ekstremt høj gennemstrømning kan det være muligt at udtømme de 4096 sekvenser pr. millisekund, hvilket potentielt kan forårsage forsinkelser.
-
Ikke-monotonitet på tværs af maskiner: Selvom IDs er monotonisk stigende på en enkelt maskine, er de muligvis ikke strengt monotone på tværs af flere maskiner.
Historie
Snowflake IDs blev introduceret af Twitter i 2010 for at imødekomme behovet for distribuerede, tids-sorterbare unikke identifikatorer. De er siden blevet vedtaget og tilpasset af mange andre virksomheder og projekter.
Eksempler
Her er implementeringer af Snowflake ID-generatorer i forskellige sprog:
1class SnowflakeGenerator {
2 constructor(epoch = 1288834974657, datacenterIdBits = 5, workerIdBits = 5, sequenceBits = 12) {
3 this.epoch = BigInt(epoch);
4 this.datacenterIdBits = datacenterIdBits;
5 this.workerIdBits = workerIdBits;
6 this.sequenceBits = sequenceBits;
7 this.maxDatacenterId = -1n ^ (-1n << BigInt(datacenterIdBits));
8 this.maxWorkerId = -1n ^ (-1n << BigInt(workerIdBits));
9 this.sequenceMask = -1n ^ (-1n << BigInt(sequenceBits));
10 this.workerIdShift = BigInt(sequenceBits);
11 this.datacenterIdShift = BigInt(sequenceBits + workerIdBits);
12 this.timestampLeftShift = BigInt(sequenceBits + workerIdBits + datacenterIdBits);
13 this.sequence = 0n;
14 this.lastTimestamp = -1n;
15 }
16
17 nextId(datacenterId, workerId) {
18 let timestamp = this.currentTimestamp();
19
20 if (timestamp < this.lastTimestamp) {
21 throw new Error('Klokken bevægede sig bagud. Nægter at generere id');
22 }
23
24 if (timestamp === this.lastTimestamp) {
25 this.sequence = (this.sequence + 1n) & this.sequenceMask;
26 if (this.sequence === 0n) {
27 timestamp = this.tilNextMillis(this.lastTimestamp);
28 }
29 } else {
30 this.sequence = 0n;
31 }
32
33 this.lastTimestamp = timestamp;
34
35 return ((timestamp - this.epoch) << this.timestampLeftShift) |
36 (BigInt(datacenterId) << this.datacenterIdShift) |
37 (BigInt(workerId) << this.workerIdShift) |
38 this.sequence;
39 }
40
41 tilNextMillis(lastTimestamp) {
42 let timestamp = this.currentTimestamp();
43 while (timestamp <= lastTimestamp) {
44 timestamp = this.currentTimestamp();
45 }
46 return timestamp;
47 }
48
49 currentTimestamp() {
50 return BigInt(Date.now());
51 }
52}
53
54// Brug
55const generator = new SnowflakeGenerator();
56const id = generator.nextId(1, 1);
57console.log(`Genereret Snowflake ID: ${id}`);
58
1import time
2import threading
3
4class SnowflakeGenerator:
5 def __init__(self, datacenter_id, worker_id, sequence=0):
6 self.datacenter_id = datacenter_id
7 self.worker_id = worker_id
8 self.sequence = sequence
9
10 self.last_timestamp = -1
11 self.epoch = 1288834974657
12
13 self.datacenter_id_bits = 5
14 self.worker_id_bits = 5
15 self.sequence_bits = 12
16
17 self.max_datacenter_id = -1 ^ (-1 << self.datacenter_id_bits)
18 self.max_worker_id = -1 ^ (-1 << self.worker_id_bits)
19
20 self.worker_id_shift = self.sequence_bits
21 self.datacenter_id_shift = self.sequence_bits + self.worker_id_bits
22 self.timestamp_left_shift = self.sequence_bits + self.worker_id_bits + self.datacenter_id_bits
23 self.sequence_mask = -1 ^ (-1 << self.sequence_bits)
24
25 self._lock = threading.Lock()
26
27 def _til_next_millis(self, last_timestamp):
28 timestamp = self._get_timestamp()
29 while timestamp <= last_timestamp:
30 timestamp = self._get_timestamp()
31 return timestamp
32
33 def _get_timestamp(self):
34 return int(time.time() * 1000)
35
36 def next_id(self):
37 with self._lock:
38 timestamp = self._get_timestamp()
39
40 if timestamp < self.last_timestamp:
41 raise ValueError("Klokken bevægede sig bagud. Nægter at generere id")
42
43 if timestamp == self.last_timestamp:
44 self.sequence = (self.sequence + 1) & self.sequence_mask
45 if self.sequence == 0:
46 timestamp = self._til_next_millis(self.last_timestamp)
47 else:
48 self.sequence = 0
49
50 self.last_timestamp = timestamp
51
52 return ((timestamp - self.epoch) << self.timestamp_left_shift) | \
53 (self.datacenter_id << self.datacenter_id_shift) | \
54 (self.worker_id << self.worker_id_shift) | \
55 self.sequence
56
57## Brug
58generator = SnowflakeGenerator(datacenter_id=1, worker_id=1)
59snowflake_id = generator.next_id()
60print(f"Genereret Snowflake ID: {snowflake_id}")
61
1import java.util.concurrent.locks.Lock;
2import java.util.concurrent.locks.ReentrantLock;
3
4public class SnowflakeGenerator {
5 private final long epoch;
6 private final long datacenterIdBits;
7 private final long workerIdBits;
8 private final long sequenceBits;
9 private final long maxDatacenterId;
10 private final long maxWorkerId;
11 private final long workerIdShift;
12 private final long datacenterIdShift;
13 private final long timestampLeftShift;
14 private final long sequenceMask;
15
16 private long datacenterId;
17 private long workerId;
18 private long sequence = 0L;
19 private long lastTimestamp = -1L;
20
21 private final Lock lock = new ReentrantLock();
22
23 public SnowflakeGenerator(long datacenterId, long workerId) {
24 this.epoch = 1288834974657L;
25 this.datacenterIdBits = 5L;
26 this.workerIdBits = 5L;
27 this.sequenceBits = 12L;
28
29 this.maxDatacenterId = ~(-1L << datacenterIdBits);
30 this.maxWorkerId = ~(-1L << workerIdBits);
31
32 this.workerIdShift = sequenceBits;
33 this.datacenterIdShift = sequenceBits + workerIdBits;
34 this.timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits;
35 this.sequenceMask = ~(-1L << sequenceBits);
36
37 if (datacenterId > maxDatacenterId || datacenterId < 0) {
38 throw new IllegalArgumentException("datacenterId kan ikke være større end maxDatacenterId eller mindre end 0");
39 }
40 if (workerId > maxWorkerId || workerId < 0) {
41 throw new IllegalArgumentException("workerId kan ikke være større end maxWorkerId eller mindre end 0");
42 }
43 this.datacenterId = datacenterId;
44 this.workerId = workerId;
45 }
46
47 public long nextId() {
48 lock.lock();
49 try {
50 long timestamp = timeGen();
51 if (timestamp < lastTimestamp) {
52 throw new RuntimeException("Klokken bevægede sig bagud. Nægter at generere id");
53 }
54
55 if (lastTimestamp == timestamp) {
56 sequence = (sequence + 1) & sequenceMask;
57 if (sequence == 0) {
58 timestamp = tilNextMillis(lastTimestamp);
59 }
60 } else {
61 sequence = 0L;
62 }
63
64 lastTimestamp = timestamp;
65
66 return ((timestamp - epoch) << timestampLeftShift) |
67 (datacenterId << datacenterIdShift) |
68 (workerId << workerIdShift) |
69 sequence;
70 } finally {
71 lock.unlock();
72 }
73 }
74
75 private long tilNextMillis(long lastTimestamp) {
76 long timestamp = timeGen();
77 while (timestamp <= lastTimestamp) {
78 timestamp = timeGen();
79 }
80 return timestamp;
81 }
82
83 private long timeGen() {
84 return System.currentTimeMillis();
85 }
86
87 public static void main(String[] args) {
88 SnowflakeGenerator generator = new SnowflakeGenerator(1, 1);
89 long id = generator.nextId();
90 System.out.println("Genereret Snowflake ID: " + id);
91 }
92}
93
1require 'time'
2
3class SnowflakeGenerator
4 def initialize(datacenter_id, worker_id, sequence = 0)
5 @datacenter_id = datacenter_id
6 @worker_id = worker_id
7 @sequence = sequence
8 @last_timestamp = -1
9 @epoch = 1288834974657
10
11 @datacenter_id_bits = 5
12 @worker_id_bits = 5
13 @sequence_bits = 12
14
15 @max_datacenter_id = -1 ^ (-1 << @datacenter_id_bits)
16 @max_worker_id = -1 ^ (-1 << @worker_id_bits)
17
18 @worker_id_shift = @sequence_bits
19 @datacenter_id_shift = @sequence_bits + @worker_id_bits
20 @timestamp_left_shift = @sequence_bits + @worker_id_bits + @datacenter_id_bits
21 @sequence_mask = -1 ^ (-1 << @sequence_bits)
22 end
23
24 def next_id
25 timestamp = (Time.now.to_f * 1000).to_i
26
27 raise 'Klokken bevægede sig bagud' if timestamp < @last_timestamp
28
29 if timestamp == @last_timestamp
30 @sequence = (@sequence + 1) & @sequence_mask
31 timestamp = til_next_millis(@last_timestamp) if @sequence == 0
32 else
33 @sequence = 0
34 end
35
36 @last_timestamp = timestamp
37
38 ((timestamp - @epoch) << @timestamp_left_shift) |
39 (@datacenter_id << @datacenter_id_shift) |
40 (@worker_id << @worker_id_shift) |
41 @sequence
42 end
43
44 private
45
46 def til_next_millis(last_timestamp)
47 timestamp = (Time.now.to_f * 1000).to_i
48 timestamp = (Time.now.to_f * 1000).to_i while timestamp <= last_timestamp
49 timestamp
50 end
51end
52
53## Brug
54generator = SnowflakeGenerator.new(1, 1)
55snowflake_id = generator.next_id
56puts "Genereret Snowflake ID: #{snowflake_id}"
57
1<?php
2
3class SnowflakeGenerator {
4 private $epoch;
5 private $datacenterIdBits;
6 private $workerIdBits;
7 private $sequenceBits;
8 private $maxDatacenterId;
9 private $maxWorkerId;
10 private $workerIdShift;
11 private $datacenterIdShift;
12 private $timestampLeftShift;
13 private $sequenceMask;
14
15 private $datacenterId;
16 private $workerId;
17 private $sequence = 0;
18 private $lastTimestamp = -1;
19
20 public function __construct($datacenterId, $workerId) {
21 $this->epoch = 1288834974657;
22 $this->datacenterIdBits = 5;
23 $this->workerIdBits = 5;
24 $this->sequenceBits = 12;
25
26 $this->maxDatacenterId = -1 ^ (-1 << $this->datacenterIdBits);
27 $this->maxWorkerId = -1 ^ (-1 << $this->workerIdBits);
28
29 $this->workerIdShift = $this->sequenceBits;
30 $this->datacenterIdShift = $this->sequenceBits + $this->workerIdBits;
31 $this->timestampLeftShift = $this->sequenceBits + $this->workerIdBits + $this->datacenterIdBits;
32 $this->sequenceMask = -1 ^ (-1 << $this->sequenceBits);
33
34 if ($datacenterId > $this->maxDatacenterId || $datacenterId < 0) {
35 throw new Exception("datacenterId kan ikke være større end maxDatacenterId eller mindre end 0");
36 }
37 if ($workerId > $this->maxWorkerId || $workerId < 0) {
38 throw new Exception("workerId kan ikke være større end maxWorkerId eller mindre end 0");
39 }
40 $this->datacenterId = $datacenterId;
41 $this->workerId = $workerId;
42 }
43
44 public function nextId() {
45 $timestamp = $this->timeGen();
46
47 if ($timestamp < $this->lastTimestamp) {
48 throw new Exception("Klokken bevægede sig bagud. Nægter at generere id");
49 }
50
51 if ($this->lastTimestamp == $timestamp) {
52 $this->sequence = ($this->sequence + 1) & $this->sequenceMask;
53 if ($this->sequence == 0) {
54 $timestamp = $this->tilNextMillis($this->lastTimestamp);
55 }
56 } else {
57 $this->sequence = 0;
58 }
59
60 $this->lastTimestamp = $timestamp;
61
62 return (($timestamp - $this->epoch) << $this->timestampLeftShift) |
63 ($this->datacenterId << $this->datacenterIdShift) |
64 ($this->workerId << $this->workerIdShift) |
65 $this->sequence;
66 }
67
68 private function tilNextMillis($lastTimestamp) {
69 $timestamp = $this->timeGen();
70 while ($timestamp <= $lastTimestamp) {
71 $timestamp = $this->timeGen();
72 }
73 return $timestamp;
74 }
75
76 private function timeGen() {
77 return floor(microtime(true) * 1000);
78 }
79}
80
81// Brug
82$generator = new SnowflakeGenerator(1, 1);
83$id = $generator->nextId();
84echo "Genereret Snowflake ID: " . $id . "\n";
85
1using System;
2using System.Threading;
3
4public class SnowflakeGenerator
5{
6 private readonly long _epoch;
7 private readonly int _datacenterIdBits;
8 private readonly int _workerIdBits;
9 private readonly int _sequenceBits;
10 private readonly long _maxDatacenterId;
11 private readonly long _maxWorkerId;
12 private readonly int _workerIdShift;
13 private readonly int _datacenterIdShift;
14 private readonly int _timestampLeftShift;
15 private readonly long _sequenceMask;
16
17 private readonly long _datacenterId;
18 private readonly long _workerId;
19 private long _sequence = 0L;
20 private long _lastTimestamp = -1L;
21
22 private readonly object _lock = new object();
23
24 public SnowflakeGenerator(long datacenterId, long workerId)
25 {
26 _epoch = 1288834974657L;
27 _datacenterIdBits = 5;
28 _workerIdBits = 5;
29 _sequenceBits = 12;
30
31 _maxDatacenterId = -1L ^ (-1L << _datacenterIdBits);
32 _maxWorkerId = -1L ^ (-1L << _workerIdBits);
33
34 _workerIdShift = _sequenceBits;
35 _datacenterIdShift = _sequenceBits + _workerIdBits;
36 _timestampLeftShift = _sequenceBits + _workerIdBits + _datacenterIdBits;
37 _sequenceMask = -1L ^ (-1L << _sequenceBits);
38
39 if (datacenterId > _maxDatacenterId || datacenterId < 0)
40 {
41 throw new ArgumentException($"datacenterId kan ikke være større end {_maxDatacenterId} eller mindre end 0");
42 }
43 if (workerId > _maxWorkerId || workerId < 0)
44 {
45 throw new ArgumentException($"workerId kan ikke være større end {_maxWorkerId} eller mindre end 0");
46 }
47 _datacenterId = datacenterId;
48 _workerId = workerId;
49 }
50
51 public long NextId()
52 {
53 lock (_lock)
54 {
55 var timestamp = TimeGen();
56
57 if (timestamp < _lastTimestamp)
58 {
59 throw new Exception("Klokken bevægede sig bagud. Nægter at generere id");
60 }
61
62 if (_lastTimestamp == timestamp)
63 {
64 _sequence = (_sequence + 1) & _sequenceMask;
65 if (_sequence == 0)
66 {
67 timestamp = TilNextMillis(_lastTimestamp);
68 }
69 }
70 else
71 {
72 _sequence = 0L;
73 }
74
75 _lastTimestamp = timestamp;
76
77 return ((timestamp - _epoch) << _timestampLeftShift) |
78 (_datacenterId << _datacenterIdShift) |
79 (_workerId << _workerIdShift) |
80 _sequence;
81 }
82 }
83
84 private long TilNextMillis(long lastTimestamp)
85 {
86 var timestamp = TimeGen();
87 while (timestamp <= lastTimestamp)
88 {
89 timestamp = TimeGen();
90 }
91 return timestamp;
92 }
93
94 private long TimeGen()
95 {
96 return DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();
97 }
98}
99
100// Brug
101class Program
102{
103 static void Main(string[] args)
104 {
105 var generator = new SnowflakeGenerator(1, 1);
106 var id = generator.NextId();
107 Console.WriteLine($"Genereret Snowflake ID: {id}");
108 }
109}
110
1package main
2
3import (
4 "fmt"
5 "sync"
6 "time"
7)
8
9type SnowflakeGenerator struct {
10 epoch int64
11 datacenterIdBits uint
12 workerIdBits uint
13 sequenceBits uint
14 maxDatacenterId int64
15 maxWorkerId int64
16 workerIdShift uint
17 datacenterIdShift uint
18 timestampLeftShift uint
19 sequenceMask int64
20
21 datacenterId int64
22 workerId int64
23 sequence int64
24 lastTimestamp int64
25
26 lock sync.Mutex
27}
28
29func NewSnowflakeGenerator(datacenterId, workerId int64) (*SnowflakeGenerator, error) {
30 g := &SnowflakeGenerator{
31 epoch: 1288834974657,
32 datacenterIdBits: 5,
33 workerIdBits: 5,
34 sequenceBits: 12,
35 lastTimestamp: -1,
36 }
37
38 g.maxDatacenterId = -1 ^ (-1 << g.datacenterIdBits)
39 g.maxWorkerId = -1 ^ (-1 << g.workerIdBits)
40
41 g.workerIdShift = g.sequenceBits
42 g.datacenterIdShift = g.sequenceBits + g.workerIdBits
43 g.timestampLeftShift = g.sequenceBits + g.workerIdBits + g.datacenterIdBits
44 g.sequenceMask = -1 ^ (-1 << g.sequenceBits)
45
46 if datacenterId > g.maxDatacenterId || datacenterId < 0 {
47 return nil, fmt.Errorf("datacenterId kan ikke være større end %d eller mindre end 0", g.maxDatacenterId)
48 }
49 if workerId > g.maxWorkerId || workerId < 0 {
50 return nil, fmt.Errorf("workerId kan ikke være større end %d eller mindre end 0", g.maxWorkerId)
51 }
52 g.datacenterId = datacenterId
53 g.workerId = workerId
54
55 return g, nil
56}
57
58func (g *SnowflakeGenerator) NextId() (int64, error) {
59 g.lock.Lock()
60 defer g.lock.Unlock()
61
62 timestamp := g.timeGen()
63
64 if timestamp < g.lastTimestamp {
65 return 0, fmt.Errorf("klokken bevægede sig bagud, nægter at generere id")
66 }
67
68 if g.lastTimestamp == timestamp {
69 g.sequence = (g.sequence + 1) & g.sequenceMask
70 if g.sequence == 0 {
71 timestamp = g.tilNextMillis(g.lastTimestamp)
72 }
73 } else {
74 g.sequence = 0
75 }
76
77 g.lastTimestamp = timestamp
78
79 return ((timestamp - g.epoch) << g.timestampLeftShift) |
80 (g.datacenterId << g.datacenterIdShift) |
81 (g.workerId << g.workerIdShift) |
82 g.sequence, nil
83}
84
85func (g *SnowflakeGenerator) tilNextMillis(lastTimestamp int64) int64 {
86 timestamp := g.timeGen()
87 for timestamp <= lastTimestamp {
88 timestamp = g.timeGen()
89 }
90 return timestamp
91}
92
93func (g *SnowflakeGenerator) timeGen() int64 {
94 return time.Now().UnixNano() / int64(time.Millisecond)
95}
96
97func main() {
98 generator, err := NewSnowflakeGenerator(1, 1)
99 if err != nil {
100 fmt.Printf("Fejl ved oprettelse af generator: %v\n", err)
101 return
102 }
103
104 id, err := generator.NextId()
105 if err != nil {
106 fmt.Printf("Fejl ved generering af ID: %v\n", err)
107 return
108 }
109
110 fmt.Printf("Genereret Snowflake ID: %d\n", id)
111}
112
Diagram
Her er en visuel repræsentation af Snowflake ID-strukturen:
Referencer
- "Annoncering af Snowflake." Twitter Engineering Blog, https://blog.twitter.com/engineering/en_us/a/2010/announcing-snowflake
- "Snowflake ID." Wikipedia, https://en.wikipedia.org/wiki/Snowflake_ID
- "Distribueret ID-generering i mikrotjenester." Medium, https://medium.com/swlh/distributed-id-generation-in-microservices-b6ce9a8dd93f
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