feat: migrate snowflake ids and refresh migrations

2025-12-02 09:04:37 +08:00
parent 462e15abbb
commit 148475fa43
174 changed files with 8020 additions and 34278 deletions
--- a/src/Core/TakeoutSaaS.Shared.Kernel/Ids/SnowflakeIdGenerator.cs
+++ b/src/Core/TakeoutSaaS.Shared.Kernel/Ids/SnowflakeIdGenerator.cs
@@ -0,0 +1,111 @@
+using System.Diagnostics;
+using System.Security.Cryptography;
+using System.Threading;
+using TakeoutSaaS.Shared.Abstractions.Ids;
+
+namespace TakeoutSaaS.Shared.Kernel.Ids;
+
+/// <summary>
+/// 基于雪花算法的长整型 ID 生成器。
+/// </summary>
+public sealed class SnowflakeIdGenerator : IIdGenerator
+{
+    private const long Twepoch = 1577836800000L; // 2020-01-01 UTC
+    private const int WorkerIdBits = 5;
+    private const int DatacenterIdBits = 5;
+    private const int SequenceBits = 12;
+
+    private const long MaxWorkerId = -1L ^ (-1L << WorkerIdBits);
+    private const long MaxDatacenterId = -1L ^ (-1L << DatacenterIdBits);
+
+    private const int WorkerIdShift = SequenceBits;
+    private const int DatacenterIdShift = SequenceBits + WorkerIdBits;
+    private const int TimestampLeftShift = SequenceBits + WorkerIdBits + DatacenterIdBits;
+    private const long SequenceMask = -1L ^ (-1L << SequenceBits);
+
+    private readonly long _workerId;
+    private readonly long _datacenterId;
+    private long _lastTimestamp = -1L;
+    private long _sequence;
+    private readonly object _syncRoot = new();
+
+    /// <summary>
+    /// 初始化生成器。
+    /// </summary>
+    /// <param name="workerId">工作节点 ID。</param>
+    /// <param name="datacenterId">机房 ID。</param>
+    public SnowflakeIdGenerator(long workerId = 0, long datacenterId = 0)
+    {
+        _workerId = Normalize(workerId, MaxWorkerId, nameof(workerId));
+        _datacenterId = Normalize(datacenterId, MaxDatacenterId, nameof(datacenterId));
+        _sequence = RandomNumberGenerator.GetInt32(0, (int)SequenceMask);
+    }
+
+    /// <inheritdoc />
+    public long NextId()
+    {
+        lock (_syncRoot)
+        {
+            var timestamp = CurrentTimeMillis();
+
+            if (timestamp < _lastTimestamp)
+            {
+                // 时钟回拨时等待到下一毫秒。
+                var wait = _lastTimestamp - timestamp;
+                Thread.Sleep(TimeSpan.FromMilliseconds(wait));
+                timestamp = CurrentTimeMillis();
+                if (timestamp < _lastTimestamp)
+                {
+                    throw new InvalidOperationException($"系统时钟回拨 {_lastTimestamp - timestamp} 毫秒，无法生成 ID。");
+                }
+            }
+
+            if (_lastTimestamp == timestamp)
+            {
+                _sequence = (_sequence + 1) & SequenceMask;
+                if (_sequence == 0)
+                {
+                    timestamp = WaitNextMillis(_lastTimestamp);
+                }
+            }
+            else
+            {
+                _sequence = 0;
+            }
+
+            _lastTimestamp = timestamp;
+
+            var id = ((timestamp - Twepoch) << TimestampLeftShift)
+                     | (_datacenterId << DatacenterIdShift)
+                     | (_workerId << WorkerIdShift)
+                     | _sequence;
+
+            Debug.Assert(id > 0);
+            return id;
+        }
+    }
+
+    private static long WaitNextMillis(long lastTimestamp)
+    {
+        var timestamp = CurrentTimeMillis();
+        while (timestamp <= lastTimestamp)
+        {
+            Thread.SpinWait(50);
+            timestamp = CurrentTimeMillis();
+        }
+
+        return timestamp;
+    }
+
+    private static long CurrentTimeMillis() => DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();
+
+    private static long Normalize(long value, long max, string name)
+    {
+        if (value < 0 || value > max)
+        {
+            throw new ArgumentOutOfRangeException(name, value, $"取值范围 0~{max}");
+        }
+
+        return value;
+    }
+}