Durable：显式检查点与受控恢复
App 提供实际检查点存储和排他锁，任务沿同一定义与累计额度显式运行或恢复。
defineDurableTask({id,revision,isState,steps}, options?) 返回 run({taskId,store},context)。store 必须提供跨所有写者有效的 exclusive、load、save。检查点 version=2，包含 definitionId/revision、nextStepIndex、attemptCount/maxAttempts、deadlineAtMs、status 和 state；必须由 App 创建，任务不会自动 seed 或查找业务。
ready 开始下一步，running 表示该步曾中断，completed 校验后返回结果，cancelled 拒绝。safe 表示这一步允许重做；reconcile 表示中断后必须走 reconcile，缺少时拒绝。尝试数在 handler 前累加并保存，成功后保存新状态和下一步；恢复不重置累计次数或 deadline。每次保存都在锁内等待，但取消不能撤销已经发生的外部提交。
App 通过显式调用启动或恢复任务，并提供持久存储、幂等键、副作用对账、重新授权和存储事务。
由简到繁的同业务示例
先用隔离内存检查点理解一次执行
入门 · Node.js
这是最小存储合同的隔离演示；真正跨进程/跨请求恢复必须换成具备排他与持久保证的 App store。
ts
import { Durable } from '@jangts/agent-core/kits/durable';
import type { DurableCheckpoint, DurableStore } from '@jangts/agent-core/kits/durable';
type State = { count: number };
const records = new Map<string, DurableCheckpoint<State>>([
['demo-task', { version: 2, definitionId: 'count', revision: '1', nextStepIndex: 0, attemptCount: 0, maxAttempts: 3, deadlineAtMs: Date.now() + 60_000, status: 'ready', state: { count: 0 } }],
]);
let tail = Promise.resolve();
// 隔离示例：进程内串行锁和内存记录，不是生产持久化实现。
const store: DurableStore<State> = {
exclusive(_id, operation) { const result = tail.then(operation); tail = result.then(() => {}, () => {}); return result; },
async load(id) { const record = records.get(id); return record && structuredClone(record); },
async save(id, record) { records.set(id, structuredClone(record)); },
};
const isState = (value: unknown): value is State => !!value && typeof value === 'object' && 'count' in value && typeof value.count === 'number';
const task = Durable.defineDurableTask<State, undefined>({
id: 'count', revision: '1', isState,
steps: [{ id: 'increment', replayPolicy: 'safe', async run(state) { return { count: state.count + 1 }; } }],
});
const context = { app: undefined, signal: new AbortController().signal };
console.log(await task.run({ taskId: 'demo-task', store }, context));
console.log(records.get('demo-task')?.attemptCount);js
import { Durable } from '@jangts/agent-core/kits/durable';
const records = new Map([
['demo-task', { version: 2, definitionId: 'count', revision: '1', nextStepIndex: 0, attemptCount: 0, maxAttempts: 3, deadlineAtMs: Date.now() + 60_000, status: 'ready', state: { count: 0 } }],
]);
let tail = Promise.resolve();
// 隔离示例：进程内串行锁和内存记录，不是生产持久化实现。
const store = {
exclusive(_id, operation) { const result = tail.then(operation); tail = result.then(() => { }, () => { }); return result; },
async load(id) { const record = records.get(id); return record && structuredClone(record); },
async save(id, record) { records.set(id, structuredClone(record)); },
};
const isState = (value) => !!value && typeof value === 'object' && 'count' in value && typeof value.count === 'number';
const task = Durable.defineDurableTask({
id: 'count', revision: '1', isState,
steps: [{ id: 'increment', replayPolicy: 'safe', async run(state) { return { count: state.count + 1 }; } }],
});
const context = { app: undefined, signal: new AbortController().signal };
console.log(await task.run({ taskId: 'demo-task', store }, context));
console.log(records.get('demo-task')?.attemptCount);同一 run 增加中断后的真实对账策略
配置 · Node.js
示例不擅自把“无法确认是否提交”解释成失败或重新执行；生产对账需查询真实业务系统。
ts
import { Durable } from '@jangts/agent-core/kits/durable';
import type { DurableCheckpoint, DurableStore } from '@jangts/agent-core/kits/durable';
type State = { count: number };
const records = new Map<string, DurableCheckpoint<State>>([
['demo-task', { version: 2, definitionId: 'count', revision: '1', nextStepIndex: 0, attemptCount: 0, maxAttempts: 3, deadlineAtMs: Date.now() + 60_000, status: 'ready', state: { count: 0 } }],
]);
let tail = Promise.resolve();
// 隔离示例：进程内串行锁和内存记录，不是生产持久化实现。
const store: DurableStore<State> = {
exclusive(_id, operation) { const result = tail.then(operation); tail = result.then(() => {}, () => {}); return result; },
async load(id) { const record = records.get(id); return record && structuredClone(record); },
async save(id, record) { records.set(id, structuredClone(record)); },
};
const isState = (value: unknown): value is State => !!value && typeof value === 'object' && 'count' in value && typeof value.count === 'number';
// 假设业务服务以 taskId 为幂等键保存真实提交结果；这里用内存 Map 演示。
const committed = new Map<string, number>();
const task = Durable.defineDurableTask<State, { key: string }>({
id: 'count', revision: '1', isState,
steps: [{ id: 'commit', replayPolicy: 'reconcile',
async run(state, { app }) {
const value = committed.get(app.key) ?? state.count + 1;
committed.set(app.key, value);
return { count: value };
},
async reconcile(state, { app }) {
const value = committed.get(app.key);
if (value === undefined) throw new Error('没有可核实的提交结果，需要 App 决定后续动作');
return { count: value };
},
}],
});
const context = { app: { key: 'demo-task' }, signal: new AbortController().signal };
console.log(await task.run({ taskId: 'demo-task', store }, context));
console.log(await task.run({ taskId: 'demo-task', store }, context)); // 已完成记录不会再次执行步骤
console.log(committed.size);js
import { Durable } from '@jangts/agent-core/kits/durable';
const records = new Map([
['demo-task', { version: 2, definitionId: 'count', revision: '1', nextStepIndex: 0, attemptCount: 0, maxAttempts: 3, deadlineAtMs: Date.now() + 60_000, status: 'ready', state: { count: 0 } }],
]);
let tail = Promise.resolve();
// 隔离示例：进程内串行锁和内存记录，不是生产持久化实现。
const store = {
exclusive(_id, operation) { const result = tail.then(operation); tail = result.then(() => { }, () => { }); return result; },
async load(id) { const record = records.get(id); return record && structuredClone(record); },
async save(id, record) { records.set(id, structuredClone(record)); },
};
const isState = (value) => !!value && typeof value === 'object' && 'count' in value && typeof value.count === 'number';
// 假设业务服务以 taskId 为幂等键保存真实提交结果；这里用内存 Map 演示。
const committed = new Map();
const task = Durable.defineDurableTask({
id: 'count', revision: '1', isState,
steps: [{ id: 'commit', replayPolicy: 'reconcile',
async run(state, { app }) {
const value = committed.get(app.key) ?? state.count + 1;
committed.set(app.key, value);
return { count: value };
},
async reconcile(state, { app }) {
const value = committed.get(app.key);
if (value === undefined)
throw new Error('没有可核实的提交结果，需要 App 决定后续动作');
return { count: value };
},
}],
});
const context = { app: { key: 'demo-task' }, signal: new AbortController().signal };
console.log(await task.run({ taskId: 'demo-task', store }, context));
console.log(await task.run({ taskId: 'demo-task', store }, context)); // 已完成记录不会再次执行步骤
console.log(committed.size);