diff --git a/.agents/notes/implemented/architecture/2026-09-19-remote-duplex-stream.i18n.yaml b/.agents/notes/implemented/architecture/2026-09-19-remote-duplex-stream.i18n.yaml new file mode 100644 index 0000000000..6981faa8db --- /dev/null +++ b/.agents/notes/implemented/architecture/2026-09-19-remote-duplex-stream.i18n.yaml @@ -0,0 +1,6 @@ +# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each +# side as of the last confirmed-consistent state. Both languages carry equal authority; +# after editing either side, bring the other along and re-record with: +# pnpm run verify-translation-pairing --write .agents/notes/implemented/architecture/2026-09-19-remote-duplex-stream.md +2026-09-19-remote-duplex-stream.md: bbfcc7763333b75f41df37bb187da38c9c4b261e +2026-09-19-remote-duplex-stream.zh.md: 5fee4d934fdba46db2e455e56fd4aaf20d50d575 diff --git a/.agents/notes/implemented/architecture/2026-09-19-remote-duplex-stream.md b/.agents/notes/implemented/architecture/2026-09-19-remote-duplex-stream.md new file mode 100644 index 0000000000..bbfcc77633 --- /dev/null +++ b/.agents/notes/implemented/architecture/2026-09-19-remote-duplex-stream.md @@ -0,0 +1,595 @@ +# Agent Note: Remote duplex stream: one kind of stream, an uplink channel, and an invocation context + +Status: implemented + +English | [中文](2026-09-19-remote-duplex-stream.zh.md) + +## Problem + +### Current state + +`dsh-api-gateway` multiplexes every Typert Remote stream over one WebSocket at the fixed path `/api/remote.mux` (`packages/api/gateway/src/stream-protocol.ts:6`). A Host method decorated with `@Remote({ mode: 'stream' })` that returns an `Iterable` or `AsyncIterable` becomes one Host-to-Client logical stream; the optional final `signal: AbortSignal` is the only reserved parameter, never enters the wire arguments, and is appended by the Gateway after the decoded business parameters (`packages/api/gateway/src/index.ts:613`). The generated method the Client receives returns a bare `AsyncIterable`. + +There are only five wire frames: + +| Direction | Frame | Definition | +| --- | --- | --- | +| Client to Host | `{ type: 'open', streamId, endpoint, payload }` | `stream-protocol.ts:243-249` | +| Client to Host | `{ type: 'cancel', streamId }` | `stream-protocol.ts:250` | +| Host to Client | `{ type: 'item', streamId, value? }` | `stream-protocol.ts:261` | +| Host to Client | `{ type: 'error', streamId, error: { code, message, details } }` | `stream-protocol.ts:262` | +| Host to Client | `{ type: 'end', streamId }` | `stream-protocol.ts:263` | + +The Client can send only open and cancel. The parser `parseRemoteStreamClientMessage` (`stream-protocol.ts:270-284`) throws on any other frame, and a Host connection that receives one closes the whole socket with 1008 (`stream-server.ts:121-125`). In short, the Gateway today supports only "a backend iterable sent to the frontend". Every feature that needs the frontend to send data to the backend continuously takes its own detour. + +A Host method also has no notion of who initiated this call: `InvokeRemoteRequest = { namespace, method, args, signal }` (`packages/api/gateway/src/types.ts:10-19`) has no caller slot, `RemoteStreamOpener` has the signature `(endpoint, payload, signal)` (`stream-server.ts:13-17`), and the WebSocket checks the cookie once, at the handshake. + +### Three unrelated uplink mechanisms + +| Feature | Uplink path | Location | Cost | +| --- | --- | --- | --- | +| Web terminal keystrokes | One unary RPC `terminal.write(agent, id, attachmentId, data)` per xterm `onData`; the Client serializes them through a promise chain and caps its own byte budget | `packages/api/terminal-controller/src/client/model.ts:193-205`; Host `src/index.ts:229-233` | One HTTP round trip and one authentication per keystroke; two carriers correlated by hand through `attachmentId`; `inputFull` when the budget is exhausted | +| File upload | A `Blob` or `ReadableStream` goes to the native `POST /api/session/uploadFileBinary` outside the Remote layer, with `duplex: 'half'` | `packages/client/file-upload/src/client/runtime.ts:198-211`; route `src/index.ts:72-80` | Bypasses Typert descriptors; no type projection | +| Answers to approvals and questions | The Host sends waterfall frames down the `$events` stream, the Client answers through a separate unary RPC `$events/result`, correlated by `clientId` plus `eventId` | `packages/api/gateway/src/client/remote-events.ts:219-224`; Host `index.ts:357-369` | A second correlation key; `index.ts:527-529` records the race this creates | + +These three mechanisms solve the same problem: the Client wants to write into a logical stream that is already open. + +### Concrete costs + +- **Aligning two carriers.** The terminal uses `attachmentId` to correlate the `follow` stream with the `write` RPC and to decide who owns input. Approvals use `clientId` to correlate the `$events` stream with the `$events/result` RPC. +- **No ordering guarantee.** A unary RPC travels over HTTP and is unordered relative to the WebSocket downlink; the terminal can preserve order only by serializing writes on the Client. +- **Separate authentication and lookup per uplink.** Every `write(agent, id, attachmentId, data)` resolves `agent`, looks up the terminal, and validates the attachment. +- **No EOF.** The Client cannot express "I am done writing"; a half-close needs yet another RPC. +- **Cancellation does not cover both halves.** Cancelling the downlink stream does not cancel queued uplink writes, and vice versa. +- **Backpressure implemented three times.** The downlink pulls the iterator at the pace of the socket write callback (`stream-server.ts:155-199`); the terminal uses a bounded follower that makes a slow consumer fail explicitly (`terminal-controller/src/stream.ts:21-32`); the uplink relies on the Client capping `maxInputBytes` itself. +- **The documentation is already stale.** `docs/api-gateway.md:160` still says Remote handles one request and one result, a sentence that lags the stream mode the README records. + +### Relation to background jobs + +The process-shaped duplex stream face of background jobs (archived as a draft PR on branch `worktree/job-stdio-stream-pair-archive`) models a job as a pair of mirrored stream faces; for the browser to attach to it, one Remote stream must carry both a downlink and an uplink. It is one motivation for this Note but not in its scope: whether jobs need a dedicated read-write stream is an architecture question for the jobs line itself. This Note covers only the transport layer. + +### Goals + +1. The transport layer has one kind of stream, duplex by nature: downlink `item` / `end` / `error`, uplink `item` / `end`, one `streamId`, one generation. +2. The uplink type and the downlink type are written in the same place: the method's return type. +3. A Host method takes its uplink from the invocation context; the invocation context also carries the caller (the Peer). +4. The Client receives a handle that can read, write, and close, not a bare `AsyncIterable`. +5. Upper-layer protocols (snapshot, journal, any business-defined stream) stay out of the transport layer. + +## Decision + +### In one sentence + +Every Remote stream accepts a Client uplink. The method's return type `RemoteStream` declares the downlink item type and the uplink item type together; the generator derives two codecs from it. A Host method takes the uplink iterator through `this.ctx.invocation.uplink()` and learns the caller through `this.ctx.invocation.peer`. The generated Client method returns a `RemoteStream` handle: `for await` reads the downlink, `send` / `end` write the uplink, `dispose` closes. Reopening after disconnection, cursor resumption, and baseline validation all belong to upper-layer protocols. + +``` + Client Host + ───────────────────────────────── ─────────────────────────────────────────── + const s = remote.job.attach(req, signal) + │ open { streamId, endpoint, payload } ───────▶ opener(endpoint, payload, uplink, peer, control) + │ │ prepareInvocation + │ s.send(v1) → item { streamId, v1 } ───────▶ inbox.push(v1) │ invocation = { request, service, peer, signal, uplink() } + │ s.send(v2) → item { streamId, v2 } ───────▶ inbox.push(v2) │ receiverContext.extend({ invocation }).get(service) + │ s.end() → end { streamId } ───────▶ inbox.end() │ method(...args, signal) + │ ◀─────── item { streamId, o1 } │ for await (v of this.ctx.invocation.uplink()) … + │ for await (o of s) … ◀─────── item { streamId, o2 } │ yield o … + │ s.dispose() → cancel { streamId } ───────▶ control.abort() │ signal 中止；uplink.return() + │ ◀─────── end | error +``` + +### Terms + +| Term | Meaning | +| --- | --- | +| Logical stream | One call identified by one `streamId`, spanning `open` to the terminal frame | +| Generation | One physical lifetime of a logical stream. The transport layer knows exactly one generation; disconnection is failure, and reopening belongs to the upper layer | +| Downlink | The Host-to-Client `item` sequence, terminated by `end` or `error` | +| Uplink | The Client-to-Host `item` sequence, terminated by `end` (half-close) or ended together with `cancel` | +| Half-close | One direction has ended while the other remains open | +| Item | One business value in one direction; every item is validated by the codec independently | +| inbox | The bounded uplink queue the Host keeps per logical stream | +| Peer | The party the connection layer admitted, one `PeerScope`; this Host has exactly one Peer, the operator | +| Invocation context | `RemoteInvocation`: the request, receiving service, Peer, cancellation signal, and uplink entry of this call | + +### Type signatures + +```text +// @deepseek-ai/dsh-typert-protocol +/** + * 一条 Remote 流。Host 面：方法返回它，运行时就是 AsyncIterable。 + * Client 面上生成方法返回的是 RemoteStreamHandle；两个名字各自只有一个含义。 + * In 是客户端可上行的项类型；缺省 never 表示该方法不读上行。 + */ +export type RemoteStream = AsyncIterable & { readonly [STREAM_UPLINK]?: In } + +// Host +@Remote({ mode: 'stream' }) +async *attach(request: JobAttachRequest, signal: AbortSignal): RemoteStream { + const uplink = this.ctx.invocation.uplink() + void (async () => { for await (const frame of uplink) … })() + yield … +} + +// 生成的 Client 签名：参数不变，返回类型不变 +attach(request: JobAttachRequest, signal?: AbortSignal): RemoteStream + +// Client 使用 +const stream = remote.job.attach(req, signal) +for await (const frame of stream) … +stream.send(frame) // 类型为 JobInputFrame +stream.end() +stream.dispose() +``` + +`RemoteStream` is an alias rather than an interface, deliberately: if the transport layer later takes a Node stream form, only the alias definition and the adapters at both ends change; method signatures, descriptors, and upper-layer protocols stay untouched. + +### Host face + +```text +/** 本次 Remote 调用的上下文。方法通过 this.ctx.invocation 读它。 */ +export interface RemoteInvocation { + readonly request: { + readonly namespace: string + readonly method: string + readonly args: Readonly> + } + /** 接收服务的 Cordis service key。 */ + readonly service: string + /** 发起调用的 Peer。进程内载体与未接纳的调用是操作者。 */ + readonly peer: PeerScope + /** 载体取消：客户端 cancel、socket 关闭、上行失败。 */ + readonly signal: AbortSignal + /** + * 本次调用的上行项。只能取一次，第二次抛错。描述符带 uplink codec 时 + * 逐项解码为 In；不带时交付 unknown，只做 JSON 安全校验。 + * 客户端 end 后迭代结束；方法结束下行时网关调用它的 return()，未消费的项丢弃。 + * 泛型 In 只是调用方的类型断言，运行时按描述符解码，不做交叉校验。 + */ + uplink(): AsyncIterable +} + +declare module '@deepseek-ai/cordis' { + interface Context { + /** 本 Context 为之派生的 Remote 调用；非 Remote 调用派生的 Context 上为 undefined。 */ + readonly invocation: RemoteInvocation | undefined + } +} +``` + +Rules: + +1. Any `mode: 'stream'` method may call `this.ctx.invocation.uplink()`; a unary method may too, but its stream ends when the method returns, so uplink items are readable only while the method runs. +2. While `uplink()` has not been called, uplink items accumulate in the inbox until the limit is exceeded (see Backpressure) or the stream ends and they are dropped. This is deliberate: a method that does not read the uplink need not know the uplink exists. +3. When `In` defaults to `never`, the descriptor has no uplink codec; the Client handle's `send` has type `never`, so nothing can be sent at compile time. If frames still arrive at runtime (from a hand-built client), they are delivered as `unknown`. +4. `this.ctx.invocation` is `undefined` on a Context not derived from a Remote call; a method that reads it handles the optional as TypeScript requires, or asserts it on the method's first line. The accessor for that property is registered once when the `TypertRemoteService` base class is constructed, so any composition that installs a Remote service can read it. + +#### How the invocation context reaches the method + +The mechanism is carried over from the `remote-client-access` branch, and the Cordis source confirms that it holds: + +- `ctx.extend(meta)` is `Object.create(parent)` plus own properties (`vendor/cordis/src/context.ts:99-107`): no registration, no fiber, nothing to release, so deriving one per call costs nothing. +- `ctx.get(service)` returns the `createTraceable(ctx, service)` proxy (`vendor/cordis/src/reflect.ts:233-234`, `utils.ts:117-125`). Reading the `ctx` property returns the accessing Context directly (`utils.ts:175`); reading a method wraps it in `createShadowMethod`, whose `apply` replaces `this` with a shadow receiver whose `ctx` is `ctx.extend({ [symbols.shadow]: origin })` (`utils.ts:149-163`). +- The Gateway therefore writes `receiverContext.extend({ invocation }).get(descriptor.service)` to obtain a per-call view and calls `Reflect.apply(method, callReceiver, args)`; inside the method body, `this.ctx.invocation` reads this call through the prototype chain. The deferred execution of an async generator body is unaffected, because `this` was bound to the shadow object at call time. + +### PeerScope + +```text +/** 一个 Peer 的不透明身份。 */ +export type PeerId = Branded<'PeerId'> + +/** 一个 Peer 在本 Host 上的会话：接纳它的一方打开与释放；ctx 拥有连接期注册。 */ +export interface PeerScope { + readonly id: PeerId + readonly ctx: Context + dispose(): Promise +} +``` + +This Host has exactly one Peer: the operator. `@deepseek-ai/dsh-client-connection` creates it with `createScope(connectionCtx, peer)` when the service applies, the same mechanism an Agent uses to create its own scope: the Peer object is the ScopeKey, `peer.ctx` carries connection-lifetime effects, and `dispose()` runs with the Connection's release and quiets the fiber. It is exposed as `connection.operator`. + +| Member | Semantics | +| --- | --- | +| `connection.operator: PeerScope` | The only Peer; lives and dies with the Connection | +| `connection.admit(request): PeerAdmission` | Runs the existing `requestRejection`: returns `{ rejection: 401 \| 403 }` when refused, otherwise `{ peer: operator }`. Future admitters plug in here | + +The Gateway's `handleUpgrade(req, socket, head, peer)` binds an opener with a fixed Peer to that socket and registers socket closure in `peer.ctx.effect`; when the scope is already inactive, it closes the socket directly with 1001 instead. When `InvokeRemoteRequest.peer?` or the `peer` parameter of `RemoteStreamOpener` is absent, the answer is the operator, so existing in-process callers change nothing; in a composition without a Connection, the operator stand-in the Gateway builds for itself is likewise created through `createScope`, with the same `dispose()` contract. Looking up a Peer by id, associating a carrier with a second Peer, and Peer open and close events all wait until the first consumer that needs multiple Peers appears. + +Not adopted: `@Access`, `AccessDeclaration`, `AccessLevel`, `AccessTarget`, `vouch` / `vouched`, the `remote/invoke` and `remote/deliver` events, `mayDeliver`, `requireVoucher`, `gateway/access-denied`. Who the Peer is and what it may do are attached by business plugins on their own through `peer.ctx` and are outside this Note. + +### Client face + +```text +/** 生成方法在 Client 面返回的句柄。与 Host 的 RemoteStream 是两个名字，从同一个入口导出。 */ +export interface RemoteStreamHandle extends AsyncIterable { + /** 发送一个上行项。非无损 JSON 值、流已终止或已 end 时抛错。 */ + send(item: In): void + /** 上行半关闭：发 end 帧。幂等。 */ + end(): void + /** 取消整条逻辑流：发 cancel 帧（未收到终止帧时），下行迭代器安静结束。 */ + dispose(): void +} +``` + +- The handle represents one generation. When the carrier is lost, `for await` fails with `RemoteStreamCarrierError` and the handle ends there; whether to reopen, and with which arguments, belongs to the upper-layer protocol. +- `send` is synchronous: it runs the `isRemoteJsonValue` check before enqueuing and throws synchronously on a value that is not lossless JSON. The browser's `WebSocket.send` has no write callback, so throttling sends would be meaningless; the Host-side inbox limit is the only backpressure point. +- When a terminal frame (`end` / `error`) arrives, the mux client stops the pump and closes the uplink queue immediately on the receive path, so later `send` / `end` throw without waiting for the consumer's next read. +- `dispose()` calls `return()` on the carrier iterator, so the `cancel` frame is sent even when nobody is reading the downlink; afterwards the handle's `next()` ends immediately and buffered items are dropped. A consumer that `break`s out of `for await` early is equivalent to `dispose()`. +- The `$stream` supervisor, `RemoteSnapshotStream`, and `RemoteJournalStream` are upper-layer tools outside the transport layer. The object their `open` factories receive is the handle itself, with unchanged `for await` behavior; exposing `send` to these upper-layer protocols is deferred. + +### Wire frames + +```text +export type RemoteStreamClientMessage = + | { readonly type: 'open'; readonly streamId: string; readonly endpoint: string; readonly payload: unknown } + | { readonly type: 'item'; readonly streamId: string; readonly value?: unknown } // 新增：上行项 + | { readonly type: 'end'; readonly streamId: string } // 新增：上行半关闭 + | { readonly type: 'cancel'; readonly streamId: string } + +/** Host 发出的帧不变。 */ +export type RemoteStreamServerMessage = + | { readonly type: 'item'; readonly streamId: string; readonly value?: unknown } + | { readonly type: 'error'; readonly streamId: string; readonly error: RemoteStreamFailure } + | { readonly type: 'end'; readonly streamId: string } +``` + +Parsing rules: `item` has exactly the keys `type` and `streamId` plus an optional `value`, and `value` must be a lossless JSON value (`isRemoteJsonValue`); `end` has exactly the keys `type` and `streamId`. Any other frame is a frame-format violation, and the socket closes with 1008. No binary frames are introduced. + +### Logical stream state machine + +#### Host side + +``` + open 帧 + (无) ─────────────────────▶ opening ──── opener 解析完成 ────▶ running + │ │ + │ item 帧: inbox.push │ item 帧: inbox.push + │ end 帧: inbox.end │ end 帧: inbox.end（上行半关闭） + │ │ 方法 yield: 发 item 帧 + │ cancel 帧 / socket 关闭 ────────▶│ cancel 帧 / socket 关闭: control.abort + ▼ ▼ + aborted ◀───────────────────────── finished（发 end 或 error 帧） +``` + +`item` frames that arrive during `opening` enter the inbox: `receive()` is synchronous and creates the `ActiveStream` and its inbox while handling the `open` frame, whereas the opener is asynchronous. Items the Client sends immediately after `open` are not lost. + +#### Client side + +``` + 调用生成方法 ──▶ 等 socket ──▶ 发 open ──▶ 句柄可用 + │ send(v): 发 item；end(): 发 end + │ 下行：inbox.next() → yield；end → 结束；error → 抛 + │ 下行先终止：send/end 抛错 + │ dispose 或调用方 signal 中止：发 cancel（未收到终止帧时） +``` + +### Half-close and termination + +| Uplink | Downlink | Result | +| --- | --- | --- | +| Client `end` | Still open | The Host's `uplink()` iteration ends; the method keeps producing. This is the stdin EOF form | +| Still open | The Host method finishes and sends `end` | The Client handle terminates, and later `send` / `end` throw; the Host calls `return()` on the `uplink` iterator and drops unconsumed items | +| Still open | The Host method throws and sends `error` | Same as above; the Client downlink fails with `RemoteError` | +| Client `dispose` or signal abort | Any | Sends `cancel`; the Host runs `control.abort()`, `cancellableStream` calls `return()` on the method iterator and then on `uplink`; no terminal frame is sent | +| Socket closes | Any | The Host aborts every stream and awaits `done`; on the Client every stream fails with `RemoteStreamCarrierError` | +| `item` received after `end` | Any | The stream fails with a `gateway/protocol` error frame and aborts; the socket stays open | +| `item` / `end` with an unknown `streamId` | Any | Ignored, like `cancel`: after the Host ends a stream and deletes its id, uplink frames still in flight from the Client are normal and must not take down the other streams on the same socket | + +### Ordering guarantees + +Frames on one socket arrive in total order: a logical stream's `open`, `item`…, `end` reach the Host in send order, and uplink items enter `uplink()` in the order of `send`. There is no cross-direction ordering guarantee between uplink and downlink; a protocol that needs request-response pairing carries its own sequence numbers. + +### Backpressure + +WebSocket has no per-stream window like HTTP/2: one connection is one serial write chain, and a slow stream holds up the other streams on the same connection. This property of the downlink is unchanged. For the uplink: + +**A bounded inbox plus whole-stream failure.** The Host meters each logical stream's inbox in UTF-8 bytes of its frames, with the limit set by the Gateway config `streamInboxBytes` (default 262144) and applied to every stream. On overflow the whole logical stream fails with `gateway/uplink-overflow`: the downlink breaks with it, an `error` frame goes to the Client, and the `uplink()` iterator ends with the same error. No data is discarded; a method that does not read its uplink while the Client keeps sending is a usage error, and the failure exposes it explicitly. + +Credit frames wait until a consumer that needs sustained high-volume uplink appears; the inbox limit is the initial credit, and adding them is incremental. + +### Security and validation + +| Item | Rule | +| --- | --- | +| Authentication | Same as today: `connection.requestRejection(req)` at upgrade; descriptor and lookup-parameter validation at open. Uplink items belong to an already authenticated stream and are not authenticated again | +| Peer | Admitted at upgrade as one `PeerScope`; `invocation.peer` of every stream on that socket is that Peer | +| Item validation | With an uplink codec, every item is decoded strictly, and a failure fails the whole stream with the existing `gateway/input-invalid` (details `{ endpoint, field: 'uplink' }`); without a codec, only JSON-safety validation applies | +| Frame size | A single frame keeps the `maxPayload` of `ws`; the inbox limit bounds the accumulated total | + +### In-process and worker carriers + +| Carrier | Change | +| --- | --- | +| `ClientConnectionRpc.open` (`packages/client/connection/src/rpc.ts:245-250`) and `RpcStreamOpen` (`client/rpc.ts:21-25`) | Append an optional `uplink?: AsyncIterable`; in process there are no frames and no inbox, the caller's iterator is the source of `uplink()` directly, and backpressure is the pace of the iterator itself | +| Worker tunnel (`packages/experimental/webworker-runtime`) | The page adds `stream-uplink-item` / `stream-uplink-end` frames; `serveStream` assembles them into an `uplink` handed to `seams.openStream`. Same-origin trusted boundary: no inbox limit, and items after `end` are dropped | +| `remote-mock` (`packages/test-support/remote-mock`) | `StreamHandle.uplink: AsyncIterable`; `rpc.open` passes it through | + +An in-process carrier with no `peer` means the operator. + +### Relation to `$events` + +`$events` is a stream on a reserved endpoint; with uplink frames, waterfall answers can become uplink items on the same `streamId`, `clientId` becomes redundant because `streamId` already identifies the generation, and `$events/result` disappears together with the race at `index.ts:527-529`. Out of scope for this Note; see Deferred. + +## Type and wire definitions + +### typert protocol (`packages/typert/protocol/src`) + +```text +// types.ts +export type RemoteStream = AsyncIterable & { readonly [STREAM_UPLINK]?: In } +export type PeerId = Branded<'PeerId'> +export interface PeerScope { readonly id: PeerId; readonly ctx: Context; dispose(): Promise } +export interface RemoteInvocation { … } // 见 Host 面 +declare module '@deepseek-ai/cordis' { interface Context { readonly invocation: RemoteInvocation | undefined } } + +export interface InvocationDescriptor { + // 既有字段不变；mode 仍只有 'stream' + readonly mode?: 'stream' + /** 上行项 codec，从返回类型 RemoteStream 的 In 生成；In 为 never 时缺席。 */ + readonly uplink?: { readonly codec: TypertCodec } + readonly cancellation?: { readonly parameter: 'signal' } + readonly result: TypertCodec +} +``` + +The `Remote` decorator, `RemoteMethodOptions`, and `RemoteMethodMarker` recognize only `mode: 'stream'`. + +### typert generator (`packages/typert/generator/src`) + +- `model.ts`: `InvocationModel.uplink?: { boundary: RemoteBoundaryModel }`. +- `analyzer.ts` `remoteResultType` (currently `~1402`): for `mode: 'stream'`, the accepted return-type wrappers are `Iterable`, `AsyncIterable`, and `RemoteStream`. `RemoteStream` is recognized the same way as the standard library's `AsyncIterable`: by symbol name plus declaring file (`types.ts` of `@deepseek-ai/dsh-typert-protocol`). The first type argument is the downlink item; when the second is present and is not `never`, an `uplink` boundary is generated under the key `${endpoint}:uplink`. +- `emitter.ts`: the descriptor literal emits `uplink: { codec }`; the generated Client signature returns `RemoteStreamHandle`. +- The parameter loop recognizes no parameter named `uplink`. + +### Two names, one entry point + +A Host method declares a stream with `RemoteStream`; the Client holds a `RemoteStreamHandle`. Both are exported from the main entry point of `@deepseek-ai/dsh-typert-protocol`, and the handle interface has no Host dependency. The generated Client contract writes the return type as `RemoteStreamHandle`. One name has one meaning: the `RemoteStream` that Client code obtains from the main entry point is always the declaration type and is never confused with the handle. + +### Gateway Host (`packages/api/gateway/src`) + +```text +// types.ts +export interface InvokeRemoteRequest { + readonly namespace: string + readonly method: string + readonly args: Readonly> + /** 上行项；缺席等价于立即结束的迭代器。 */ + readonly uplink?: AsyncIterable + /** 发起调用的 Peer；缺席即操作者。 */ + readonly peer?: PeerScope + readonly signal?: AbortSignal +} + +export interface TypertGatewayWireStream { + open: (endpoint: string, payload: unknown, uplink: AsyncIterable, peer: PeerScope | undefined, signal: AbortSignal) => Promise> + failure: (error: unknown) => RemoteStreamFailure +} + +// stream-server.ts +export type RemoteStreamOpener = ( + endpoint: string, + payload: unknown, + uplink: AsyncIterable, + peer: PeerScope, + control: AbortController, +) => Promise> + +// index.ts Config 新增 +/** 每条逻辑流的上行 inbox 上限，按帧的 UTF-8 字节计（默认 262144）。 */ +readonly streamInboxBytes?: number +``` + +`prepareInvocation`: + +```text +const args = await Promise.all(descriptor.parameters.map(parameter => this.resolveParameter(parameter, request.args, endpoint))) +const signal = request.signal ?? NEVER_ABORTED_SIGNAL +const invocation = new GatewayInvocation( + { namespace: request.namespace, method: request.method, args: request.args }, + descriptor.service, + request.peer ?? this.operatorPeer(), + signal, + new UplinkDecoder(request.uplink ?? EMPTY_ASYNC_ITERABLE, descriptor.uplink?.codec, endpoint, control), +) +const callReceiver = receiverContext.extend({ invocation }).get(descriptor.service) as object +if (descriptor.cancellation !== undefined) args.push(signal) +``` + +`GatewayInvocation.uplink()` returns the decoder on the first call and throws on the second. `UplinkDecoder` is a hand-written iterator: with a codec it runs `decode(codec, value, endpoint, 'uplink')` per item and, on failure, calls `control.abort(failure)` and throws; without a codec it applies only the `isRemoteJsonValue` check. The `finally` of `cancellableStream` closes the decoder first (`invocation.close()`) and then awaits the method iterator's `return()`, so a method blocked on `uplink.next()` can exit. The mode branches are the existing two, unary and stream. SRC fallback: the descriptor has no `uplink` codec, and `uplink()` delivers `unknown`. + +### Gateway Host mux (`stream-server.ts`) + +```text +interface ActiveStream { readonly control: AbortController; readonly inbox: UplinkInbox; done: Promise } + +/** 有界上行队列；作为 uplink() 的源被迭代。 */ +class UplinkInbox implements AsyncIterable, AsyncIterator { + constructor(maxBytes: number, onOverflow: (error: RemoteError) => void) + push(value: unknown, frameBytes: number): void // ended 后 push 使流以 gateway/protocol 失败；超限调用 onOverflow + end(): void // 幂等 + fail(error: unknown): void // 取消或载体关闭时让迭代器以错误结束 + next() / return() // 手写：next 与失败竞速，return 立即释放 +} +``` + +`receive(text)` dispatch: + +``` +open : 已存在 → 抛错（socket 1008）；否则创建 { control, inbox, done }，启动 pump +item : 不存在 → 忽略；否则 inbox.push(value, bytes) +end : 不存在 → 忽略；否则 inbox.end() +cancel : 不存在 → 忽略；否则 control.abort(new Error('Remote stream cancelled')) +``` + +`pump` passes the inbox and the socket's Peer to the opener and calls `inbox.fail(...)` in its `finally`. An abort whose reason is a `RemoteError` is sent by the pump as an `error` frame (a failure raised by the Gateway or the mux); an abort whose reason is a plain `Error` (cancel, socket closure) sends no terminal frame. + +### Gateway Client (`packages/api/gateway/src/client`) + +- `prepareInvocation` strips no uplink parameter; the positional parameters are the business parameters plus the optional `signal`. +- `invokeStream` returns a `RemoteStreamHandle`: it holds an uplink queue internally, `send` enqueues and a pump sends the `item` frames, `end` sends the `end` frame, and `dispose` aborts the generation signal. The downlink is still the iterator that `openRemoteStream` returns. +- `RemoteStreamMuxClient.open(endpoint, payload, signal, uplink?)`: after sending the `open` frame it starts the uplink pump, which sends one `item` per item and `end` when the source ends; when the downlink terminates or the signal aborts, it stops the pump and calls the source's `return()` (without awaiting, so a keyboard-style generator cannot hang it); when the source throws, it calls `inbox.fail(error)`, the downlink fails with that error, and `finally` sends `cancel` under the existing rules. The pump checks `this.socket === socket`, so an old generation never sends frames on a new socket. +- In-process carrier: `connection.rpc.open(channel, endpoint, payload, signal, uplink)`. + +## Placement + +| Package | Carries | +| --- | --- | +| `dsh-typert-protocol` (`types.ts`, `index.ts`) | `RemoteStream`, `RemoteStreamHandle`, `PeerId`, `PeerScope`, `RemoteInvocation`, the `ctx.invocation` declaration merge, `InvocationDescriptor.uplink`; the decorator recognizes only `mode: 'stream'`; `TypertRemoteService` registers the `invocation` accessor when constructed | +| `dsh-typert-registry` | Load-time validation that `uplink.codec` is a valid strict codec | +| `dsh-typert-generator` (`model.ts`, `analyzer.ts`, `emitter.ts`) | `remoteResultType` recognizes `RemoteStream` and generates the `uplink` boundary; the descriptor emits `uplink: { codec }`; the generated Client signature returns `RemoteStreamHandle`; the parameter loop accepts only business parameters and a final `signal` | +| `dsh-client-connection` (`operator-peer.ts`, `rpc.ts`, `rpc-host.ts`, `index.ts`) | The operator `PeerScope`; `connection.operator` and `admit`; the `/api` and upgrade routes obtain the Peer through `admit`; the optional `uplink` of `rpc.open` | +| `dsh-api-gateway` Host (`stream-protocol.ts`, `stream-server.ts`, `types.ts`, `index.ts`) | `item` / `end` frames; `UplinkInbox`; `Config.streamInboxBytes`; `GatewayInvocation` and `extend({ invocation })`; `UplinkDecoder`; `handleUpgrade(req, socket, head, peer)`; `operatorPeer()` | +| `dsh-api-gateway` Client (`client/index.ts`, `client/stream-client.ts`) | `invokeStream` returns the handle; the uplink pump is driven by the handle's queue | +| `dsh-webworker-runtime`, `dsh-remote-mock` | The worker tunnel's two uplink frames and the `serveStream` assembly; `StreamHandle.uplink`; the direct proxy returns the real handle | +| Documentation | The READMEs of gateway, the api group, connection, protocol, and generator; `docs/api-gateway`; the type-equiv blocks of `docs/subsystems/typert`; the config and Cordis catalogs | + +## Key sequences + +### Open, uplink, half-close, downlink end + +``` +Client 调用方 mux client mux server gateway Host 方法 + │ attach(req) │ │ │ │ + │───────────────────▶│ open { id, ep, payload } ─────────────────▶│ 创建 inbox │ + │ s.send(v1) │ item { id, v1 } ──────────────────────────▶│ inbox.push(v1) │ + │ │ │ │ prepareInvocation │ + │ │ │ │ extend({ invocation }) │ + │ │ │ │───── method(req, signal) ─────────▶│ + │ │ │ │ │ uplink() → v1 + │ s.send(v2) │ item { id, v2 } ──────────────────────────▶│ inbox.push(v2) │ → v2 + │ s.end() │ end { id } ───────────────────────────────▶│ inbox.end() │ 迭代结束 + │◀── yield o1 ───────│◀────────────────────── item { id, o1 } ────│◀── yield o1 ────────│ + │◀── 结束 ───────────│◀────────────────────── end { id } ─────────│◀── 方法返回 ─────────│ gateway 调 uplink.return() +``` + +### Client dispose + +``` +Client 调用方 mux client mux server gateway Host 方法 + │ s.dispose() │ │ │ │ + │───────────────────▶│ 停泵；源 return()（不等待） │ │ + │◀── 迭代器结束 ─────│ cancel { id } ────────────────────────────▶│ control.abort() │ + │ │ │ │ cancellableStream: iterator.return() ──▶│ finally 清理 + │ │ │ │ uplink.return() │ + │ │ │ 不发终止帧 │ │ +``` + +### inbox overflow + +``` +Client 调用方 mux client mux server gateway / Host 方法 + │ s.send(vN) │ item { id, vN } ─────▶│ inbox.push: bytes > streamInboxBytes │ + │ │ │ onOverflow → control.abort(RemoteError uplink-overflow) + │ │ │ │ uplink() 以该错误结束；方法迭代器 return() + │◀── throw ──────────│◀── error { id, uplink-overflow } ─────────│ pump 因 reason 是 RemoteError 发 error 帧 +``` + +## Boundary matrix + +| Event | opening | running | Uplink ended | Downlink terminated | +| --- | --- | --- | --- | --- | +| `item` received | Buffered in the inbox | Into the inbox | The stream fails with `gateway/protocol` | Ignored | +| `end` received | inbox.end | inbox.end | Idempotent | Ignored | +| `cancel` received | abort | abort | abort | Ignored | +| inbox overflow | The stream fails with `uplink-overflow` | Same | Impossible | Impossible | +| Decode failure | Impossible | The stream fails with `input-invalid` | Same | Impossible | +| Host method finishes | Impossible | Sends `end`; `uplink.return()` | Sends `end` | Already sent | +| Host method throws | Sends `error` | Sends `error`; `uplink.return()` | Sends `error` | Already sent | +| Socket closes | abort, await done | Same | Same | Nothing | +| Client `send` | Queued, sent after open | Sent | Throws | Throws | +| Client `end` | Recorded, sent after open | Sent | Idempotent | Ignored | +| Client-side downlink ends first | Impossible | Stop the pump; source `return()`; no `end` sent | Nothing | Nothing | + +## Error codes + +| Code | When | +| --- | --- | +| `gateway/input-invalid` | Existing: a parameter codec fails to decode; new: an uplink item fails to decode | +| `gateway/uplink-overflow` | New: the inbox exceeds `streamInboxBytes` | +| `gateway/protocol` | New: an `item` after `end` | +| `gateway/cancelled` | Existing: `signal` aborted | + +New codes are registered in `packages/api/gateway/src/remote-error-codes.ts` and in the README's error-code section. + +## Minimal echo method + +`packages/api/gateway/tests/echo-stream.host.spec.ts` runs the same method through the WebSocket carrier and through the in-process carrier: + +```text +class EchoService extends TypertRemoteService { + constructor(ctx: Context) { super(ctx, 'echo', { namespace: 'echo' }) } + + @Remote({ mode: 'stream' }) + async *echo(prefix: string, signal: AbortSignal): RemoteStream { + for await (const item of this.ctx.invocation!.uplink()) { + signal.throwIfAborted() + yield `${prefix}${item}` + } + } +} + +// 客户端 +const stream = remote.echo.echo('> ') +stream.send('a'); stream.send('b'); stream.end() +const replies: string[] = [] +for await (const reply of stream) replies.push(reply) // ['> a', '> b'] +``` + +## Alternatives considered + +**A separate `mode: 'duplex'` plus a reserved parameter `uplink: AsyncIterable` alongside `signal`.** Special logic everywhere: the analyzer must recognize a second reserved parameter and its position rules, the generated signature gains a parameter, load time must validate `duplex ⟺ uplink`, and because the mux does not know the method mode, the Gateway must reject uplink frames on behalf of `'stream'` methods. Duplex is an inherent property of the transport-layer stream, not a mode of the method: the carrier already has `streamId`, `open`, and `cancel`; the uplink adds just two more frames, which any stream can receive and which are simply not sent when unused. + +**Declaring the uplink type in a decorator option, `@Remote({ mode: 'stream', uplink: 'JobInputFrame' })`.** A string reference to a type name is not checked by the compiler and breaks on rename. The return-type alias puts both types in one compiler-visible place. + +**Passing a schema at runtime: `uplink(schema)`.** Bypasses the generator, the Client loses type projection, and it splits from the "strict codec per item" system. The codec still comes from the generator; the generic in the method is only an assertion. + +**Having the analyzer cross-check the hand-written generic of `uplink()` against the return type.** A business-specific check whose mistakes the caller bears, consistent with the other hand-written assertions in the repository; not added. + +**A transport-layer handle with reopening, cursors, and a `reopen` hook.** Reopening after disconnection belongs to the upper-layer protocol: a job resumes through an `opened` frame carrying `from` and a client that remembers `next` and calls again; snapshot and journal each have their own anchors and classification. The transport layer knows one generation. + +**Putting the Client's `send` on the `AsyncIterable` the generated method returns.** Hanging methods on an `AsyncIterable` is unconventional; the handle type `RemoteStreamHandle` extends it explicitly. + +**Copying the Access mechanism.** Access control is business semantics, served by `vouch` and the `remote/invoke` waterfall; this Note only needs "whose stream is this", and `PeerScope` suffices. + +**Keeping unary RPC for the uplink.** One HTTP round trip, one authentication, and one lookup per uplink; two carriers with no ordering relation that only Client-side serialization can order; no EOF; cancellation that does not cover both halves; a hand-made correlation key per feature. + +**A native HTTP request body stream.** A one-shot request body with no association to the downlink stream, bypassing Typert descriptors, and browser support for full-duplex fetch cannot be relied on. + +**One dedicated WebSocket per duplex stream.** Loses the authentication, heartbeat, and multiplexing shared with the existing downlink streams, and every feature manages its own socket lifecycle. + +**WebTransport or HTTP/2 bidirectional streams.** They have per-stream flow control, but support on the browser and Node sides, proxy traversal, and the Electron carrier are all immature; adding two frames to the existing mux is orders of magnitude cheaper than replacing the transport layer. + +## Consequences + +- **Bought**: one stream with two directions, so interactive scenarios such as terminal keystrokes, approval answers, and background-job stdin no longer each build their own "one stream plus one unary"; a Host method knows its caller; the uplink and downlink types are declared in one place, the return type, and uplink items are validated per item as strictly as downlink items; the generated output and wire frames of existing `AsyncIterable` methods and unary methods are completely unchanged. +- **`this.ctx.invocation` is `undefined` outside a Remote call**, so a method that reads it must handle the optional; a service method invoked only directly in process correctly reads `undefined`. +- **The inbox limit applies to every stream**: a method that does not read its uplink fails as a whole when it receives many uplink frames. This is a deliberate explicit failure, recorded in the README. +- **The operator is the only Peer**, and `admit` is the only admission point; the first consumer that needs a second Peer must add opening, association, and events in `dsh-client-connection`. +- **No cross-direction ordering guarantee between uplink and downlink**; a protocol that needs request-response pairing carries its own sequence numbers. +- **Upper-layer protocols do not yet expose `send`**: consumers of `$stream`, snapshot, and journal use only the downlink today; the object they receive is already the handle. +- **The worker tunnel behaves differently from the WebSocket carrier**: no inbox limit, and items after `end` are dropped, because page to worker is a same-origin trusted boundary. + +## Testing + +- `packages/api/gateway/tests/echo-stream.host.spec.ts`: the same echo method passes through the WebSocket carrier and through the in-process carrier. +- Gateway Host: exact-key validation in frame parsing; `UplinkInbox` buffering during opening, `item` after `end`, overflow, ignored unknown `streamId`, and cleanup on socket closure; `UplinkDecoder` delivery with and without a codec and abort on decode failure; `uplink()` taken only once; the `extend({ invocation })` view and the origin of `peer`; `cancellableStream` closing the uplink before `return()`. +- Gateway Client: the handle's `send` (JSON validation, queued before open, throws after termination), idempotent `end`, `dispose` driving the `cancel` frame and ending later reads; the pump's three exits; the pump stopping as soon as a terminal frame arrives. +- typert: the analyzer's handling of `RemoteStream`, `RemoteStream`, `never`, and the existing `AsyncIterable`; decorator options; registry load-time validation. +- connection: the three outcomes of `admit`, 401, 403, and the operator; the operator reaching handlers through the bridge and the shared handler; release with the Connection. +- remote-mock and the worker tunnel: uplink pass-through; the direct proxy returning the real handle. +- Existing stream and unary method tests pass without changed expectations. + +## Deferred + +- `$stream` / snapshot / journal expose the handle's `send` to upper-layer protocols. +- Web terminal: one `attach` stream replaces `follow` plus `write` plus `resize`, and `attachmentId` retires. +- Duplex `$events`: waterfall answers become uplink items on the same `streamId`, and `$events/result` and `clientId` retire. +- Credit frames: wait for a consumer that needs sustained high-volume uplink; the inbox limit is the initial credit. +- The `streamInboxBytes` default of 262144 is far more than keyboard and stdin need; if the first consumer is terminal paste, it may be aligned with the `maxInputBytes` of `terminal-controller`. +- A Host-initiated half-close frame (the Host stops reading the uplink but keeps writing the downlink): no consumer; not added. +- `uplink()` on unary methods: it can read items that arrive while the method runs, semantically valid but of doubtful use; allowed, noted in the README. + +## Related + +- [Remote event delivery](2026-08-10-remote-event-delivery.md): the unary `$events/result` answer path; the duplex `$events` item under Deferred partially supersedes it once it lands. +- [Session history and event transport](2026-08-18-session-history-and-event-transport.md): the `$stream()` supervisor and the journal / snapshot protocols above it, which this note leaves unchanged. +- [Web sidebar terminal](../feature/2026-09-09-web-sidebar-terminal.md): the unary terminal `write` and `attachmentId`; the `attach` stream under Deferred replaces it once it lands. diff --git a/.agents/notes/implemented/architecture/2026-09-19-remote-duplex-stream.zh.md b/.agents/notes/implemented/architecture/2026-09-19-remote-duplex-stream.zh.md index fc5e43db2e..5fee4d934f 100644 --- a/.agents/notes/implemented/architecture/2026-09-19-remote-duplex-stream.zh.md +++ b/.agents/notes/implemented/architecture/2026-09-19-remote-duplex-stream.zh.md @@ -100,7 +100,7 @@ Host 方法也没有"这次调用是谁发起的"这个概念：`InvokeRemoteReq * Client 面上生成方法返回的是 RemoteStreamHandle；两个名字各自只有一个含义。 * In 是客户端可上行的项类型；缺省 never 表示该方法不读上行。 */ -export type RemoteStream = AsyncIterable +export type RemoteStream = AsyncIterable & { readonly [STREAM_UPLINK]?: In } // Host @Remote({ mode: 'stream' }) @@ -315,7 +315,7 @@ credit 帧留待需要持续大流量上行的消费者出现时再加；inbox ```text // types.ts -export type RemoteStream = AsyncIterable +export type RemoteStream = AsyncIterable & { readonly [STREAM_UPLINK]?: In } export type PeerId = Branded<'PeerId'> export interface PeerScope { readonly id: PeerId; readonly ctx: Context; dispose(): Promise } export interface RemoteInvocation { … } // 见 Host 面 @@ -587,3 +587,9 @@ for await (const reply of stream) replies.push(reply) // ['> a', '> b'] - `streamInboxBytes` 默认值 262144 对键盘与 stdin 远超需要；若第一个消费者是终端粘贴，可能与 `terminal-controller` 的 `maxInputBytes` 对齐。 - Host 发起的半关闭帧（Host 不再读上行但继续写下行）：没有消费者，不加。 - unary 方法的 `uplink()`：能读到方法运行期间到达的项，语义成立但用处存疑；允许，README 注明。 + +## 相关 + +- [Remote 事件投递](2026-08-10-remote-event-delivery.zh.md)：`$events/result` 的 unary 回答路径；「后续」里的双工 `$events` 落地后部分取代它。 +- [会话历史与事件传输](2026-08-18-session-history-and-event-transport.zh.md)：`$stream()` 监督器与其上的 journal / snapshot 协议，本 Note 不改它们。 +- [Web 侧边栏终端](../feature/2026-09-09-web-sidebar-terminal.zh.md)：终端按键的 unary `write` 与 `attachmentId`；「后续」里的 `attach` 流落地后取代它。