feat(M01-C): 建立MySQL异步任务基础

backend/src/tasks/task-repository.ts

@@ -0,0 +1,177 @@
+import type { PoolConnection, ResultSetHeader, RowDataPacket } from 'mysql2/promise';
+import type { MySqlPool } from '../db/mysql.js';
+
+export const taskTypes = [
+  'notification.dispatch',
+  'order.advance',
+  'device.command',
+  'refund.query',
+  'statistics.aggregate',
+  'outbox.publish'
+] as const;
+
+export type TaskType = (typeof taskTypes)[number];
+export type TaskStatus =
+  | 'PENDING'
+  | 'RUNNING'
+  | 'RETRY'
+  | 'SUCCEEDED'
+  | 'FAILED'
+  | 'COMPENSATION_REQUIRED'
+  | 'CANCELLED';
+
+export interface AsyncTask {
+  id: string;
+  tenantId: string;
+  taskType: TaskType;
+  idempotencyKey: string;
+  payload: unknown;
+  status: TaskStatus;
+  attempts: number;
+  maxAttempts: number;
+}
+
+interface TaskRow extends RowDataPacket {
+  id: string;
+  tenantId: string;
+  taskType: TaskType;
+  idempotencyKey: string;
+  payload: string | object;
+  status: TaskStatus;
+  attempts: number;
+  maxAttempts: number;
+}
+
+export interface EnqueueTaskInput {
+  tenantId: string;
+  taskType: TaskType;
+  idempotencyKey: string;
+  payload: unknown;
+  priority?: number;
+  availableAt?: Date;
+  maxAttempts?: number;
+}
+
+export class TaskRepository {
+  constructor(private readonly pool: MySqlPool) {}
+
+  async enqueue(input: EnqueueTaskInput): Promise<{ id: string; created: boolean }> {
+    const [result] = await this.pool.execute<ResultSetHeader>(
+      `INSERT IGNORE INTO qipai_async_tasks
+        (tenant_id, task_type, idempotency_key, payload, priority, available_at, max_attempts)
+       VALUES (?, ?, ?, CAST(? AS JSON), ?, ?, ?)`,
+      [
+        input.tenantId,
+        input.taskType,
+        input.idempotencyKey,
+        JSON.stringify(input.payload),
+        input.priority ?? 0,
+        input.availableAt ?? new Date(),
+        input.maxAttempts ?? 8
+      ]
+    );
+    if (result.insertId > 0) {
+      return { id: String(result.insertId), created: true };
+    }
+    const [rows] = await this.pool.execute<Array<RowDataPacket & { id: string }>>(
+      `SELECT id FROM qipai_async_tasks
+       WHERE tenant_id = ? AND task_type = ? AND idempotency_key = ?`,
+      [input.tenantId, input.taskType, input.idempotencyKey]
+    );
+    if (!rows[0]) throw new Error('Idempotent task lookup failed after duplicate insert.');
+    return { id: String(rows[0].id), created: false };
+  }
+
+  async claimNext(workerId: string, leaseMs: number): Promise<AsyncTask | null> {
+    const connection = await this.pool.getConnection();
+    try {
+      await connection.beginTransaction();
+      await this.recoverExpiredLease(connection);
+      const [rows] = await connection.execute<TaskRow[]>(
+        `SELECT id, tenant_id AS tenantId, task_type AS taskType,
+                idempotency_key AS idempotencyKey, payload, status,
+                attempts, max_attempts AS maxAttempts
+         FROM qipai_async_tasks
+         WHERE status IN ('PENDING', 'RETRY')
+           AND available_at <= UTC_TIMESTAMP(3)
+         ORDER BY priority DESC, available_at ASC, id ASC
+         LIMIT 1
+         FOR UPDATE SKIP LOCKED`
+      );
+      const row = rows[0];
+      if (!row) {
+        await connection.commit();
+        return null;
+      }
+
+      await connection.execute(
+        `UPDATE qipai_async_tasks
+         SET status = 'RUNNING',
+             lease_owner = ?,
+             lease_expires_at = DATE_ADD(UTC_TIMESTAMP(3), INTERVAL ? MICROSECOND),
+             attempts = attempts + 1,
+             last_error = NULL
+         WHERE id = ?`,
+        [workerId, leaseMs * 1000, row.id]
+      );
+      await connection.commit();
+      return {
+        ...row,
+        id: String(row.id),
+        tenantId: String(row.tenantId),
+        status: 'RUNNING',
+        attempts: row.attempts + 1,
+        payload: typeof row.payload === 'string' ? JSON.parse(row.payload) : row.payload
+      };
+    } catch (error) {
+      await connection.rollback();
+      throw error;
+    } finally {
+      connection.release();
+    }
+  }
+
+  async complete(taskId: string, workerId: string): Promise<boolean> {
+    const [result] = await this.pool.execute<ResultSetHeader>(
+      `UPDATE qipai_async_tasks
+       SET status = 'SUCCEEDED', completed_at = UTC_TIMESTAMP(3),
+           lease_owner = NULL, lease_expires_at = NULL
+       WHERE id = ? AND status = 'RUNNING' AND lease_owner = ?`,
+      [taskId, workerId]
+    );
+    return result.affectedRows === 1;
+  }
+
+  async fail(task: AsyncTask, workerId: string, error: unknown): Promise<TaskStatus> {
+    const terminal = task.attempts >= task.maxAttempts;
+    const nextStatus: TaskStatus = terminal ? 'COMPENSATION_REQUIRED' : 'RETRY';
+    const delayMs = retryDelayMs(task.attempts);
+    const message = error instanceof Error ? error.message : String(error);
+    const [result] = await this.pool.execute<ResultSetHeader>(
+      `UPDATE qipai_async_tasks
+       SET status = ?, available_at = DATE_ADD(UTC_TIMESTAMP(3), INTERVAL ? MICROSECOND),
+           lease_owner = NULL, lease_expires_at = NULL, last_error = ?
+       WHERE id = ? AND status = 'RUNNING' AND lease_owner = ?`,
+      [nextStatus, delayMs * 1000, message.slice(0, 1000), task.id, workerId]
+    );
+    if (result.affectedRows !== 1) {
+      throw new Error(`Task ${task.id} lease was lost before failure could be recorded.`);
+    }
+    return nextStatus;
+  }
+
+  private async recoverExpiredLease(connection: PoolConnection): Promise<void> {
+    await connection.execute(
+      `UPDATE qipai_async_tasks
+       SET status = 'RETRY', lease_owner = NULL, lease_expires_at = NULL,
+           available_at = UTC_TIMESTAMP(3),
+           last_error = COALESCE(last_error, 'worker lease expired')
+       WHERE status = 'RUNNING' AND lease_expires_at < UTC_TIMESTAMP(3)`
+    );
+  }
+}
+
+export function retryDelayMs(attempts: number): number {
+  const exponent = Math.max(0, Math.min(attempts - 1, 20));
+  return Math.min(60 * 60 * 1000, 1000 * 2 ** exponent);
+}