agent-orchestrator/packages/web/server/mux-websocket.ts

1429 lines
50 KiB
TypeScript

/**
* Multiplexed WebSocket server for terminal multiplexing.
* Manages multiple terminal connections over a single persistent WebSocket.
*
* Session updates are delivered via polling of Next.js /api/sessions/patches
* every 3s, then broadcast to all subscribed clients via WebSocket.
*/
import { WebSocketServer, WebSocket } from "ws";
import { spawn } from "node:child_process";
import * as fs from "node:fs";
import { createRequire } from "node:module";
import { type Socket, connect as netConnect } from "node:net";
import { dirname, join } from "node:path";
import {
DEFAULT_DASHBOARD_NOTIFICATION_LIMIT,
getEnvDefaults,
getDashboardNotificationStorePath,
getNodePtyPrebuildsSubdir,
isWindows,
loadConfig,
normalizeDashboardNotificationLimit,
recordActivityEvent,
readDashboardNotificationsFromFile,
type DashboardNotificationRecord,
} from "@aoagents/ao-core";
import {
findTmux,
resolveTmuxSession,
resolvePipePath,
tmuxHasSession,
validateSessionId,
} from "./tmux-utils.js";
// These types mirror src/lib/mux-protocol.ts exactly.
// tsconfig.server.json constrains rootDir to "server/", so we cannot import
// across the boundary. Keep both in sync when updating the protocol.
// ── Client → Server ──
type ClientMessage =
| { ch: "terminal"; id: string; type: "data"; data: string; projectId?: string }
| { ch: "terminal"; id: string; type: "resize"; cols: number; rows: number; projectId?: string }
| { ch: "terminal"; id: string; type: "open"; projectId?: string; tmuxName?: string }
| { ch: "terminal"; id: string; type: "close"; projectId?: string }
| { ch: "system"; type: "ping" }
| { ch: "subscribe"; topics: Array<"sessions" | "notifications"> };
// ── Server → Client ──
type ServerMessage =
| { ch: "terminal"; id: string; type: "data"; data: string; projectId?: string }
| { ch: "terminal"; id: string; type: "exited"; code: number; projectId?: string }
| { ch: "terminal"; id: string; type: "opened"; projectId?: string }
| { ch: "terminal"; id: string; type: "error"; message: string; projectId?: string }
| { ch: "sessions"; type: "snapshot"; sessions: SessionPatch[] }
| { ch: "sessions"; type: "error"; error: string }
| {
ch: "notifications";
type: "snapshot" | "append";
notifications: DashboardNotificationRecord[];
limit: number;
}
| { ch: "notifications"; type: "error"; error: string }
| { ch: "system"; type: "pong" }
| { ch: "system"; type: "error"; message: string };
// Mirrors AttentionLevel in src/lib/types.ts — keep in sync.
type AttentionLevel = "merge" | "action" | "respond" | "review" | "pending" | "working" | "done";
interface SessionPatch {
id: string;
status: string;
activity: string | null;
attentionLevel: AttentionLevel;
lastActivityAt: string;
}
/**
* Manages polling of session patches from Next.js /api/sessions/patches.
* Broadcasts to all subscribed callbacks.
* Lazily starts polling on first subscriber, stops when the last one leaves.
*/
export class SessionBroadcaster {
private subscribers = new Set<(sessions: SessionPatch[]) => void>();
private errorSubscribers = new Set<(error: string) => void>();
private intervalId: ReturnType<typeof setInterval> | null = null;
private polling = false;
// Tracks the last fetch outcome so we only emit ui.session_broadcast_failed on
// the healthy → failing transition (not every 3s during an outage).
private lastFetchOk = true;
private readonly baseUrl: string;
private readonly authHeader: string | null;
constructor(nextPort: string) {
this.baseUrl = `http://localhost:${nextPort}`;
const password = process.env.AO_REMOTE_AUTH_PASSWORD;
this.authHeader = password
? `Basic ${Buffer.from(`${process.env.AO_REMOTE_AUTH_USER || "ao"}:${password}`).toString("base64")}`
: null;
}
/**
* Subscribe to session patches and errors. Returns an unsubscribe function.
* Sends an immediate snapshot to the new subscriber, then polling updates.
*/
subscribe(
callback: (sessions: SessionPatch[]) => void,
onError?: (error: string) => void,
): () => void {
const wasEmpty = this.subscribers.size === 0;
this.subscribers.add(callback);
if (onError) this.errorSubscribers.add(onError);
// Immediately send a one-off snapshot to just this new subscriber
void this.fetchSnapshot().then((result) => {
if (result.sessions && this.subscribers.has(callback)) {
try {
callback(result.sessions);
} catch {
// Isolate subscriber errors so one bad subscriber doesn't break others
}
} else if (result.error && onError && this.errorSubscribers.has(onError)) {
try {
onError(result.error);
} catch {
// Isolate subscriber errors
}
}
});
// Start polling if this is the first subscriber
if (wasEmpty) {
this.intervalId = setInterval(() => {
if (this.polling) return;
this.polling = true;
void this.fetchSnapshot()
.then((result) => {
if (result.sessions && this.intervalId !== null) this.broadcast(result.sessions);
else if (result.error && this.intervalId !== null) this.broadcastError(result.error);
})
.finally(() => {
this.polling = false;
});
}, 3000);
}
return () => {
this.subscribers.delete(callback);
if (onError) this.errorSubscribers.delete(onError);
if (this.subscribers.size === 0) {
this.disconnect();
}
};
}
private broadcast(sessions: SessionPatch[]): void {
for (const callback of this.subscribers) {
try {
callback(sessions);
} catch (err) {
console.error("[MuxServer] Session broadcast subscriber threw:", err);
}
}
}
private broadcastError(error: string): void {
for (const callback of this.errorSubscribers) {
try {
callback(error);
} catch (err) {
console.error("[MuxServer] Session error subscriber threw:", err);
}
}
}
/** One-shot HTTP fetch of the current session list. */
private async fetchSnapshot(): Promise<{
sessions: SessionPatch[] | null;
error: string | null;
}> {
const controller = new AbortController();
const timeoutId = setTimeout(() => controller.abort(), 4000);
try {
const res = await fetch(`${this.baseUrl}/api/sessions/patches`, {
signal: controller.signal,
...(this.authHeader ? { headers: { Authorization: this.authHeader } } : {}),
});
clearTimeout(timeoutId);
if (!res.ok) {
const msg = `Session fetch failed: HTTP ${res.status}`;
console.warn(`[SessionBroadcaster] ${msg}`);
this.recordFetchFailure(msg, { httpStatus: res.status });
return { sessions: null, error: msg };
}
const data = (await res.json()) as { sessions?: SessionPatch[] };
this.lastFetchOk = true;
return { sessions: data.sessions ?? null, error: null };
} catch (err) {
clearTimeout(timeoutId);
const msg = err instanceof Error ? err.message : String(err);
console.warn("[SessionBroadcaster] fetchSnapshot error:", msg);
this.recordFetchFailure(msg);
return { sessions: null, error: msg };
}
}
/**
* Emit ui.session_broadcast_failed once per healthy→failing transition.
* The broadcaster polls every 3s; emitting on every failure during a long
* outage would flood the events table (~20/min). Recovery resets the flag.
*/
private recordFetchFailure(message: string, extra?: Record<string, unknown>): void {
if (!this.lastFetchOk) return;
this.lastFetchOk = false;
recordActivityEvent({
source: "ui",
kind: "ui.session_broadcast_failed",
level: "warn",
summary: `session broadcaster fetch failed: ${message}`,
data: {
url: `${this.baseUrl}/api/sessions/patches`,
errorMessage: message,
...extra,
},
});
}
private disconnect(): void {
if (this.intervalId !== null) {
clearInterval(this.intervalId);
this.intervalId = null;
}
}
}
function notificationKey(record: DashboardNotificationRecord): string {
return `${record.id}:${record.receivedAt}`;
}
function readDashboardLimit(configPath: string | undefined): number {
if (!configPath) return DEFAULT_DASHBOARD_NOTIFICATION_LIMIT;
try {
const config = loadConfig(configPath);
const dashboardConfig = config.notifiers?.["dashboard"];
return normalizeDashboardNotificationLimit(dashboardConfig?.["limit"]);
} catch (err) {
const message = err instanceof Error ? err.message : String(err);
console.warn("[NotificationBroadcaster] Could not read dashboard notifier limit:", message);
return DEFAULT_DASHBOARD_NOTIFICATION_LIMIT;
}
}
/**
* Polls the dashboard notification JSONL store and broadcasts changes to mux
* subscribers. The store is config-scoped and survives dashboard reloads.
*/
export class NotificationBroadcaster {
private subscribers = new Set<
(
notifications: DashboardNotificationRecord[],
type: "snapshot" | "append",
limit: number,
) => void
>();
private errorSubscribers = new Set<(error: string) => void>();
private intervalId: ReturnType<typeof setInterval> | null = null;
private lastRecords: DashboardNotificationRecord[] = [];
private readonly configPath: string | undefined;
private readonly storePath: string | null;
constructor(configPath = process.env["AO_CONFIG_PATH"]) {
this.configPath = configPath;
this.storePath = configPath ? getDashboardNotificationStorePath(configPath) : null;
}
subscribe(
callback: (
notifications: DashboardNotificationRecord[],
type: "snapshot" | "append",
limit: number,
) => void,
onError?: (error: string) => void,
): () => void {
const wasEmpty = this.subscribers.size === 0;
this.subscribers.add(callback);
if (onError) this.errorSubscribers.add(onError);
const snapshot = this.fetchSnapshot();
if (wasEmpty) {
this.lastRecords = snapshot.notifications;
}
try {
callback(snapshot.notifications, "snapshot", snapshot.limit);
} catch {
// Isolate subscriber errors so one bad socket does not break others.
}
if (snapshot.error && onError) {
try {
onError(snapshot.error);
} catch {
// Isolate subscriber errors.
}
}
if (wasEmpty) {
this.intervalId = setInterval(() => {
const result = this.fetchSnapshot();
if (result.error) {
this.broadcastError(result.error);
return;
}
const previousKeys = new Set(this.lastRecords.map(notificationKey));
const appended = result.notifications.filter(
(record) => !previousKeys.has(notificationKey(record)),
);
const trimmed = result.notifications.length < this.lastRecords.length;
this.lastRecords = result.notifications;
if (appended.length > 0 && !trimmed) {
this.broadcast(appended, "append", result.limit);
} else if (appended.length > 0 || trimmed) {
this.broadcast(result.notifications, "snapshot", result.limit);
}
}, 1000);
}
return () => {
this.subscribers.delete(callback);
if (onError) this.errorSubscribers.delete(onError);
if (this.subscribers.size === 0) {
this.disconnect();
}
};
}
private fetchSnapshot(): {
notifications: DashboardNotificationRecord[];
error: string | null;
limit: number;
} {
const limit = readDashboardLimit(this.configPath);
if (!this.storePath) return { notifications: [], error: null, limit };
try {
return {
notifications: readDashboardNotificationsFromFile(this.storePath, limit),
error: null,
limit,
};
} catch (err) {
const message = err instanceof Error ? err.message : String(err);
console.warn("[NotificationBroadcaster] fetchSnapshot error:", message);
return { notifications: [], error: message, limit };
}
}
private broadcast(
notifications: DashboardNotificationRecord[],
type: "snapshot" | "append",
limit: number,
): void {
for (const callback of this.subscribers) {
try {
callback(notifications, type, limit);
} catch (err) {
console.error("[MuxServer] Notification broadcast subscriber threw:", err);
}
}
}
private broadcastError(error: string): void {
for (const callback of this.errorSubscribers) {
try {
callback(error);
} catch (err) {
console.error("[MuxServer] Notification error subscriber threw:", err);
}
}
}
private disconnect(): void {
if (this.intervalId !== null) {
clearInterval(this.intervalId);
this.intervalId = null;
}
}
}
// node-pty is an optionalDependency — load dynamically
/* eslint-disable @typescript-eslint/consistent-type-imports -- node-pty is optional; static import would crash if missing */
type IPty = import("node-pty").IPty;
type PtySpawn = typeof import("node-pty").spawn;
type PtySpawnOptions = Parameters<PtySpawn>[2];
let ptySpawn: PtySpawn | undefined;
/* eslint-enable @typescript-eslint/consistent-type-imports */
const nodePtyRequire = createRequire(import.meta.url);
export function resolveNodePtySpawnHelperPath(): string | null {
const override = process.env.AO_NODE_PTY_SPAWN_HELPER_PATH;
if (override) return override;
try {
const packageJsonPath = nodePtyRequire.resolve("node-pty/package.json");
return join(dirname(packageJsonPath), "prebuilds", getNodePtyPrebuildsSubdir(), "spawn-helper");
} catch {
return null;
}
}
function isPosixSpawnpFailure(err: unknown): boolean {
return err instanceof Error && err.message.includes("posix_spawnp");
}
function repairNodePtySpawnHelper(): string | null {
if (isWindows()) return null;
const spawnHelperPath = resolveNodePtySpawnHelperPath();
if (!spawnHelperPath || !fs.existsSync(spawnHelperPath)) return null;
fs.chmodSync(spawnHelperPath, 0o755);
return spawnHelperPath;
}
try {
const nodePty = await import("node-pty");
ptySpawn = nodePty.spawn;
} catch (err) {
console.warn("[MuxServer] node-pty not available — mux server will be disabled.", err);
}
interface ManagedTerminal {
id: string;
tmuxSessionId: string;
pty: IPty | null;
subscribers: Set<(data: string) => void>;
exitCallbacks: Set<(exitCode: number) => void>;
buffer: string[];
bufferBytes: number;
reattachAttempts: number;
ptyLostEmitted: boolean;
/**
* Pending grace-period timer that resets reattachAttempts when the
* currently-attached PTY survives REATTACH_RESET_GRACE_MS. Tracked so
* cleanup paths (last-subscriber unsubscribe, subsequent re-attach) can
* clear it and avoid keeping the dead PTY/terminal closure references
* reachable for up to 5 s after teardown.
*/
resetTimer?: ReturnType<typeof setTimeout>;
}
const RING_BUFFER_MAX = 50 * 1024; // 50KB max per terminal
const WS_BUFFER_HIGH_WATERMARK = 64 * 1024; // 64KB
const MAX_REATTACH_ATTEMPTS = 3;
/**
* Grace period a freshly-attached PTY must survive before its successful
* attach is allowed to reset the re-attach counter. Prevents tight crash
* loops (e.g. attaching to a tmux session that no longer exists) from
* gaming the MAX_REATTACH_ATTEMPTS cap by resetting the counter to 0
* between every failed attempt.
*
* 5 s is comfortably longer than the ~40 ms a doomed `tmux attach-session`
* takes to exit, while still being short enough that a healthy PTY which
* crashes hours later gets a fresh retry budget.
*/
const REATTACH_RESET_GRACE_MS = 5_000;
/**
* TerminalManager manages PTY processes independently of WebSocket connections.
* A single manager instance is shared across all mux connections.
*/
export class TerminalManager {
private terminals = new Map<string, ManagedTerminal>();
private TMUX: string;
private spawnHelperRepairAttempted = false;
constructor(tmuxPath?: string) {
const resolved = tmuxPath ?? findTmux();
if (!resolved) {
throw new Error("tmux not available on this platform");
}
this.TMUX = resolved;
}
private terminalKey(id: string, projectId?: string): string {
return projectId ? `${projectId}:${id}` : id;
}
private spawnTmuxPty(args: string[], options: PtySpawnOptions): IPty {
if (!ptySpawn) {
throw new Error("node-pty not available");
}
try {
return ptySpawn(this.TMUX, args, options);
} catch (err) {
if (this.spawnHelperRepairAttempted || !isPosixSpawnpFailure(err)) {
throw err;
}
this.spawnHelperRepairAttempted = true;
try {
const repairedPath = repairNodePtySpawnHelper();
if (repairedPath) {
console.warn(
`[MuxServer] node-pty posix_spawnp failed; set executable bit on ${repairedPath} and retrying once.`,
);
} else {
console.warn(
"[MuxServer] node-pty posix_spawnp failed; spawn-helper was not found, retrying once.",
);
}
} catch (repairErr) {
const message = repairErr instanceof Error ? repairErr.message : String(repairErr);
console.warn(
`[MuxServer] node-pty posix_spawnp failed; chmod spawn-helper failed (${message}), retrying once.`,
);
}
return ptySpawn(this.TMUX, args, options);
}
}
/**
* Open/attach to a terminal. If already open, just return.
* If has subscribers but PTY crashed, re-attach.
*/
open(id: string, projectId?: string, tmuxName?: string): string {
if (!validateSessionId(id)) {
throw new Error(`Invalid session ID: ${id}`);
}
const key = this.terminalKey(id, projectId);
const existing = this.terminals.get(key);
const tmuxSessionId =
tmuxName ??
existing?.tmuxSessionId ??
resolveTmuxSession(id, this.TMUX, undefined, undefined, projectId);
if (!tmuxSessionId) {
throw new Error(`Session not found: ${id}`);
}
// Get or create terminal entry
let terminal = this.terminals.get(key);
if (!terminal) {
terminal = {
id,
tmuxSessionId,
pty: null,
subscribers: new Set(),
exitCallbacks: new Set(),
buffer: [],
bufferBytes: 0,
reattachAttempts: 0,
ptyLostEmitted: false,
};
this.terminals.set(key, terminal);
}
// If PTY is already attached, we're done
if (terminal.pty) {
return tmuxSessionId;
}
// tmux 3.4 only honours the `=` exact-match prefix on has-session and
// attach-session; set-option silently ignores it, so we use the bare id
// here. The `=`-prefixed form is built below for attach-session.
// Enable mouse mode
const mouseProc = spawn(this.TMUX, ["set-option", "-t", tmuxSessionId, "mouse", "on"]);
mouseProc.on("error", (err) => {
console.error(`[MuxServer] Failed to set mouse mode for ${tmuxSessionId}:`, err.message);
});
// Hide the status bar
const statusProc = spawn(this.TMUX, ["set-option", "-t", tmuxSessionId, "status", "off"]);
statusProc.on("error", (err) => {
console.error(`[MuxServer] Failed to hide status bar for ${tmuxSessionId}:`, err.message);
});
// Build environment
const platformDefaults = getEnvDefaults();
const homeDir = platformDefaults.HOME;
const env = {
HOME: platformDefaults.HOME,
SHELL: platformDefaults.SHELL,
USER: platformDefaults.USER,
PATH: process.env.PATH || platformDefaults.PATH,
TERM: "xterm-256color",
LANG: process.env.LANG || "en_US.UTF-8",
TMPDIR: platformDefaults.TMPDIR,
};
// Spawn PTY — use `=`-prefixed exact-match target so we never attach to
// a session whose name happens to be a prefix of the requested id.
const exactTmuxTarget = `=${tmuxSessionId}`;
const pty = this.spawnTmuxPty(["attach-session", "-t", exactTmuxTarget], {
name: "xterm-256color",
cols: 80,
rows: 24,
cwd: homeDir,
env,
});
terminal.pty = pty;
// Schedule a grace-period reset of the re-attach counter. We only
// consider an attach "really successful" if the PTY survives long
// enough to suggest the underlying tmux session is actually usable.
// The closure-captured `pty` reference is compared with terminal.pty
// so a stale timer cannot reset the counter for a PTY that has
// already exited or been replaced by re-attach. Any previously-
// scheduled timer (from a now-replaced PTY) is cleared so we don't
// keep its closure references reachable until the timer fires.
if (terminal.resetTimer) {
clearTimeout(terminal.resetTimer);
}
terminal.resetTimer = setTimeout(() => {
terminal.resetTimer = undefined;
if (terminal.pty === pty) {
terminal.reattachAttempts = 0;
terminal.ptyLostEmitted = false;
}
}, REATTACH_RESET_GRACE_MS);
terminal.resetTimer.unref();
// Wire up data events
pty.onData((data: string) => {
// Push to all subscribers — isolate each callback so a throw in one
// (e.g. a closed ws.send) doesn't abort the loop or skip the buffer.
for (const callback of terminal.subscribers) {
try {
callback(data);
} catch (err) {
console.error("[MuxServer] Subscriber callback threw:", err);
}
}
// Append to ring buffer
terminal.buffer.push(data);
terminal.bufferBytes += Buffer.byteLength(data, "utf8");
// Trim buffer if over limit
while (terminal.bufferBytes > RING_BUFFER_MAX && terminal.buffer.length > 0) {
const removed = terminal.buffer.shift() ?? "";
terminal.bufferBytes -= Buffer.byteLength(removed, "utf8");
}
});
// Handle PTY exit
//
// Async: the has-session probe shells out via promisified execFile and
// must be awaited. node-pty fires onExit on the main thread; a sync
// probe would freeze the entire web server (every WebSocket, HTTP
// request, in-flight terminal) for up to the subprocess timeout when
// tmux is slow to respond.
pty.onExit(async ({ exitCode }) => {
console.log(`[MuxServer] PTY exited for ${id} with code ${exitCode}`);
terminal.pty = null;
let reattachError: string | undefined;
// Skip the re-attach loop entirely when the underlying tmux session is
// gone (e.g. user pressed Ctrl-C in the pane and the launch command
// exited, taking the only window with it). Without this guard we
// burn three doomed attach-session spawns and emit a noisy
// "Max re-attach attempts reached" log line for what is actually a
// clean user-initiated termination — see issue #1756. The
// MAX_REATTACH_ATTEMPTS bound from #1640 still covers tmux server
// hiccups where the session does still exist.
if (terminal.subscribers.size > 0 && !(await tmuxHasSession(this.TMUX, tmuxSessionId))) {
console.log(`[MuxServer] tmux session ${tmuxSessionId} is gone, not re-attaching`);
if (terminal.resetTimer) {
clearTimeout(terminal.resetTimer);
terminal.resetTimer = undefined;
}
if (!terminal.ptyLostEmitted) {
terminal.ptyLostEmitted = true;
recordActivityEvent({
projectId,
sessionId: id,
source: "ui",
kind: "ui.terminal_pty_lost",
level: "warn",
summary: `terminal PTY exited (code ${exitCode}) — tmux session gone`,
data: {
sessionId: id,
exitCode,
reattachAttempts: terminal.reattachAttempts,
maxReattachAttempts: MAX_REATTACH_ATTEMPTS,
reattachExhausted: false,
reattachSkipped: true,
tmuxSessionPresent: false,
subscriberCount: terminal.subscribers.size,
},
});
}
for (const cb of terminal.exitCallbacks) {
cb(exitCode);
}
return;
}
// Re-attach if subscribers are still present, up to MAX_REATTACH_ATTEMPTS.
// The cap prevents an unbounded respawn loop when the PTY crashes immediately
// after every attach (e.g. resource exhaustion or a broken tmux session).
// The counter is reset by a delayed timer in open() once the new PTY has
// survived REATTACH_RESET_GRACE_MS — see the comment on that constant.
// Resetting here would defeat the cap: when ao stop kills the tmux session
// out from under a still-subscribed dashboard, attach-session exits ~40 ms
// after spawn and the loop runs at ~80 spawns/sec, exhausting the system
// PTY pool in seconds (issue #1639).
if (terminal.subscribers.size > 0 && terminal.reattachAttempts < MAX_REATTACH_ATTEMPTS) {
terminal.reattachAttempts += 1;
console.log(
`[MuxServer] Re-attaching to ${id} (attempt ${terminal.reattachAttempts}/${MAX_REATTACH_ATTEMPTS})`,
);
try {
this.open(id, projectId, tmuxSessionId);
if (!terminal.ptyLostEmitted) {
terminal.ptyLostEmitted = true;
recordActivityEvent({
projectId,
sessionId: id,
source: "ui",
kind: "ui.terminal_pty_lost",
level: "warn",
summary: `terminal PTY exited (code ${exitCode}) — reattached`,
data: {
sessionId: id,
exitCode,
reattachAttempts: terminal.reattachAttempts,
maxReattachAttempts: MAX_REATTACH_ATTEMPTS,
reattachExhausted: false,
reattachRecovered: true,
subscriberCount: terminal.subscribers.size,
},
});
}
return; // re-attached — don't notify exit
} catch (err) {
reattachError = err instanceof Error ? err.message : String(err);
console.error(`[MuxServer] Failed to re-attach ${id}:`, err);
}
} else if (terminal.reattachAttempts >= MAX_REATTACH_ATTEMPTS) {
console.error(`[MuxServer] Max re-attach attempts reached for ${id}, giving up`);
}
// PTY actually died (vs user closed browser): only emit when subscribers
// are still attached — otherwise the exit is just normal cleanup.
// Keep this event one-shot for the terminal entry. Clients may re-open
// the same terminal after a failed reattach; repeated PTY exits should
// not flood the activity log for the same loss condition.
if (terminal.subscribers.size > 0 && !terminal.ptyLostEmitted) {
terminal.ptyLostEmitted = true;
recordActivityEvent({
projectId,
sessionId: id,
source: "ui",
kind: "ui.terminal_pty_lost",
level: "warn",
summary: `terminal PTY exited (code ${exitCode})${
terminal.reattachAttempts >= MAX_REATTACH_ATTEMPTS ? " — reattach exhausted" : ""
}`,
data: {
sessionId: id,
exitCode,
reattachAttempts: terminal.reattachAttempts,
maxReattachAttempts: MAX_REATTACH_ATTEMPTS,
reattachExhausted: terminal.reattachAttempts >= MAX_REATTACH_ATTEMPTS,
subscriberCount: terminal.subscribers.size,
...(reattachError ? { reattachError } : {}),
},
});
}
// Notify subscribers that the terminal has exited (re-attach failed or no subscribers)
for (const cb of terminal.exitCallbacks) {
cb(exitCode);
}
});
console.log(`[MuxServer] Opened terminal ${id} (tmux: ${tmuxSessionId})`);
return tmuxSessionId;
}
/**
* Write data to the PTY if attached
*/
write(id: string, data: string, projectId?: string): void {
const terminal = this.terminals.get(this.terminalKey(id, projectId));
if (terminal?.pty) {
terminal.pty.write(data);
}
}
/**
* Resize the PTY if attached
*/
resize(id: string, cols: number, rows: number, projectId?: string): void {
const terminal = this.terminals.get(this.terminalKey(id, projectId));
if (terminal?.pty) {
terminal.pty.resize(cols, rows);
}
}
/**
* Subscribe to terminal data. Returns unsubscribe function.
* Automatically opens the terminal if needed.
* @param onExit - called when the PTY exits and cannot be re-attached
*/
subscribe(
id: string,
projectId: string | undefined,
callback: (data: string) => void,
onExit?: (exitCode: number) => void,
): () => void {
// Ensure terminal is open
this.open(id, projectId);
const key = this.terminalKey(id, projectId);
const terminal = this.terminals.get(key);
if (!terminal) {
throw new Error(`Failed to open terminal: ${id}`);
}
// Add subscriber
terminal.subscribers.add(callback);
if (onExit) terminal.exitCallbacks.add(onExit);
// Return unsubscribe function
return () => {
terminal.subscribers.delete(callback);
if (onExit) terminal.exitCallbacks.delete(onExit);
// Kill PTY and clean up when the last subscriber leaves
if (terminal.subscribers.size === 0) {
if (terminal.resetTimer) {
clearTimeout(terminal.resetTimer);
terminal.resetTimer = undefined;
}
if (terminal.pty) {
terminal.pty.kill();
terminal.pty = null;
}
this.terminals.delete(key);
}
};
}
/**
* Get buffered data for a terminal
*/
getBuffer(id: string, projectId?: string): string {
const terminal = this.terminals.get(this.terminalKey(id, projectId));
if (!terminal) return "";
return terminal.buffer.join("");
}
}
// ── Windows Pipe Relay (extracted for testability) ──
const intentionalWinPipeCloses = new WeakSet<Socket>();
/** Minimal WebSocket-like interface for the pipe relay handler */
export interface WsSink {
send(data: string): void;
readonly readyState: number;
}
/** Dependencies injected into the pipe relay handler */
export interface PipeRelayDeps {
connect: (path: string) => Socket;
resolvePipePath: (id: string, projectId?: string) => string | null;
}
/**
* Handle a Windows terminal message by relaying through named pipes.
* Extracted from the WebSocket connection handler for testability.
*/
export function handleWindowsPipeMessage(
msg: {
id: string;
type: string;
data?: string;
cols?: number;
rows?: number;
projectId?: string;
},
ws: WsSink,
winPipes: Map<string, Socket>,
winPipeBuffers: Map<string, Buffer>,
deps: PipeRelayDeps,
): void {
const WS_OPEN = 1; // WebSocket.OPEN
const { id, type, projectId } = msg;
// MuxProvider keys subscribers under `${projectId}:${id}` when projectId is
// provided, so every outbound terminal message must echo projectId back —
// otherwise the client routes by id alone and the subscriber bucket
// mismatches, leaving the xterm pane blank on /projects/[id]/sessions/[id].
const echo = projectId ? { projectId } : {};
// Project-scoped pipe-map key: matches the Unix `subscriptionKey` shape so
// two projects sharing a sessionId on the same mux connection don't collide
// on the same socket/buffer entry.
const pipeKey = projectId ? `${projectId}:${id}` : id;
// The Unix path validates inside TerminalManager.open(). The Windows pipe
// relay bypasses TerminalManager entirely, so validate here too — `id`
// becomes a map key and is constructed into a pipe path downstream.
if (!validateSessionId(id)) {
if (ws.readyState === WS_OPEN) {
ws.send(
JSON.stringify({
ch: "terminal",
id,
type: "error",
message: "invalid session id",
...echo,
}),
);
}
return;
}
if (type === "open") {
if (winPipes.has(pipeKey)) {
ws.send(JSON.stringify({ ch: "terminal", id, type: "opened", ...echo }));
} else {
const pipePath = deps.resolvePipePath(id, projectId);
if (!pipePath) {
throw new Error(`No PTY host pipe found for session ${id}`);
}
const pipeSocket = deps.connect(pipePath);
winPipes.set(pipeKey, pipeSocket);
winPipeBuffers.set(pipeKey, Buffer.alloc(0));
let ptyLostEmitted = false;
const recordWindowsPtyLost = (
reason: "pipe_closed" | "host_not_alive" | "pipe_error",
extra?: Record<string, unknown>,
): void => {
if (ptyLostEmitted || ws.readyState !== WS_OPEN) return;
ptyLostEmitted = true;
recordActivityEvent({
projectId,
sessionId: id,
source: "ui",
kind: "ui.terminal_pty_lost",
level: "warn",
summary:
reason === "host_not_alive"
? `terminal PTY host reported not alive for ${id}`
: reason === "pipe_error"
? `terminal PTY host pipe errored for ${id}`
: `terminal PTY host pipe closed for ${id}`,
data: {
sessionId: id,
transport: "windows_pipe",
reason,
...extra,
},
});
};
pipeSocket.on("error", (err) => {
recordWindowsPtyLost("pipe_error", { errorMessage: err.message });
winPipes.delete(pipeKey);
winPipeBuffers.delete(pipeKey);
pipeSocket.destroy();
if (ws.readyState === WS_OPEN) {
ws.send(
JSON.stringify({
ch: "terminal",
id,
type: "error",
message: `PTY host not available: ${err.message}`,
...echo,
}),
);
}
});
pipeSocket.on("connect", () => {
if (ws.readyState === WS_OPEN) {
ws.send(JSON.stringify({ ch: "terminal", id, type: "opened", ...echo }));
}
pipeSocket.on("data", (chunk: Buffer) => {
const existing = winPipeBuffers.get(pipeKey) ?? Buffer.alloc(0);
let buf = Buffer.concat([existing, chunk]);
winPipeBuffers.set(pipeKey, buf);
while (buf.length >= 5) {
const msgType = buf.readUInt8(0);
const length = buf.readUInt32BE(1);
if (buf.length < 5 + length) break;
const payload = buf.subarray(5, 5 + length);
buf = buf.subarray(5 + length);
winPipeBuffers.set(pipeKey, buf);
if (msgType === 0x01 && ws.readyState === WS_OPEN) {
ws.send(
JSON.stringify({
ch: "terminal",
id,
type: "data",
data: payload.toString("utf-8"),
...echo,
}),
);
}
if (msgType === 0x07) {
try {
const status = JSON.parse(payload.toString("utf-8")) as { alive: boolean };
if (!status.alive && ws.readyState === WS_OPEN) {
recordWindowsPtyLost("host_not_alive");
ws.send(JSON.stringify({ ch: "terminal", id, type: "exited", code: 0, ...echo }));
}
} catch {
/* ignore parse errors */
}
}
}
});
pipeSocket.on("close", () => {
winPipes.delete(pipeKey);
winPipeBuffers.delete(pipeKey);
const intentionalClose = intentionalWinPipeCloses.delete(pipeSocket);
if (ws.readyState === WS_OPEN) {
if (!intentionalClose) {
recordWindowsPtyLost("pipe_closed");
}
ws.send(JSON.stringify({ ch: "terminal", id, type: "exited", code: 0, ...echo }));
}
});
});
}
} else if (type === "data" && msg.data !== undefined) {
const pipeSocket = winPipes.get(pipeKey);
if (pipeSocket) {
const inputBuf = Buffer.from(msg.data, "utf-8");
const header = Buffer.alloc(5);
header.writeUInt8(0x02, 0);
header.writeUInt32BE(inputBuf.length, 1);
pipeSocket.write(Buffer.concat([header, inputBuf]));
}
} else if (type === "resize" && msg.cols !== undefined && msg.rows !== undefined) {
const pipeSocket = winPipes.get(pipeKey);
if (pipeSocket) {
const resizePayload = Buffer.from(JSON.stringify({ cols: msg.cols, rows: msg.rows }));
const header = Buffer.alloc(5);
header.writeUInt8(0x03, 0);
header.writeUInt32BE(resizePayload.length, 1);
pipeSocket.write(Buffer.concat([header, resizePayload]));
}
} else if (type === "close") {
const pipeSocket = winPipes.get(pipeKey);
if (pipeSocket) {
intentionalWinPipeCloses.add(pipeSocket);
pipeSocket.end();
winPipes.delete(pipeKey);
winPipeBuffers.delete(pipeKey);
}
}
}
/**
* Create a mux WebSocket server (noServer mode).
* Returns the WebSocketServer instance for manual upgrade routing.
*/
export function createMuxWebSocket(tmuxPath?: string | null): WebSocketServer | null {
// On Windows, we use named pipe relay instead of node-pty/tmux.
// Allow the server to be created without ptySpawn on Windows.
if (!ptySpawn && !isWindows()) {
console.warn("[MuxServer] node-pty not available — mux WebSocket will be disabled");
return null;
}
// On Windows, terminal I/O goes through named pipe relay — no TerminalManager needed.
const terminalManager =
ptySpawn && !isWindows() ? new TerminalManager(tmuxPath ?? undefined) : null;
const nextPort = process.env.PORT || "3000";
const broadcaster = new SessionBroadcaster(nextPort);
const notificationBroadcaster = new NotificationBroadcaster();
const wss = new WebSocketServer({ noServer: true });
wss.on("connection", (ws, request) => {
console.log("[MuxServer] New mux connection");
const connectedAt = Date.now();
// Best-effort remote addr — proxy headers if present, else socket peer.
const xff = request?.headers["x-forwarded-for"];
const xffStr = Array.isArray(xff) ? xff[0] : xff;
const remoteAddr =
(typeof xffStr === "string" ? xffStr.split(",")[0]?.trim() : undefined) ??
request?.socket?.remoteAddress ??
undefined;
recordActivityEvent({
source: "ui",
kind: "ui.terminal_connected",
level: "info",
summary: "mux WebSocket connection opened",
data: { remoteAddr },
});
const subscriptions = new Map<string, () => void>();
// Windows: named pipe sockets keyed by session ID
const winPipes = new Map<string, ReturnType<typeof netConnect>>();
// Windows: framing buffers keyed by session ID
const winPipeBuffers = new Map<string, Buffer>();
let sessionUnsubscribe: (() => void) | null = null;
let notificationUnsubscribe: (() => void) | null = null;
let missedPongs = 0;
let heartbeatLostEmitted = false;
const MAX_MISSED_PONGS = 3;
// Heartbeat: send native WebSocket ping every 15s.
// Browsers automatically respond to native pings with pong frames —
// no application-level code is needed on the client side.
const heartbeatInterval = setInterval(() => {
if (ws.readyState === WebSocket.OPEN) {
// Send the ping first so it counts as a sent-but-unanswered probe
ws.ping();
missedPongs += 1;
if (missedPongs >= MAX_MISSED_PONGS) {
console.log("[MuxServer] Too many missed pongs, terminating connection");
if (!heartbeatLostEmitted) {
heartbeatLostEmitted = true;
recordActivityEvent({
source: "ui",
kind: "ui.terminal_heartbeat_lost",
level: "warn",
summary: `mux WebSocket heartbeat lost (${missedPongs} missed pongs)`,
data: {
missedPongs,
maxMissedPongs: MAX_MISSED_PONGS,
connectionAgeMs: Date.now() - connectedAt,
remoteAddr,
subscriberCount: subscriptions.size,
},
});
}
ws.terminate();
}
}
}, 15_000);
// Native pong resets the missed counter
ws.on("pong", () => {
missedPongs = 0;
});
/**
* Handle incoming messages
*/
ws.on("message", (data) => {
try {
const msg = JSON.parse(data.toString("utf8")) as ClientMessage;
if (msg.ch === "system") {
if (msg.type === "ping") {
const pong: ServerMessage = { ch: "system", type: "pong" };
ws.send(JSON.stringify(pong));
}
} else if (msg.ch === "terminal") {
const { id, type } = msg;
const projectId = "projectId" in msg ? msg.projectId : undefined;
const subscriptionKey = projectId ? `${projectId}:${id}` : id;
try {
if (type === "open") {
if (isWindows()) {
handleWindowsPipeMessage(
msg as {
id: string;
type: string;
projectId?: string;
data?: string;
cols?: number;
rows?: number;
},
ws,
winPipes,
winPipeBuffers,
{ connect: netConnect, resolvePipePath },
);
} else {
// --- Unix: tmux path with project scoping ---
if (!terminalManager) throw new Error("Terminal manager not available");
terminalManager.open(id, projectId, "tmuxName" in msg ? msg.tmuxName : undefined);
// Send opened confirmation (idempotent — safe to send on re-open)
const openedMsg: ServerMessage = {
ch: "terminal",
id,
type: "opened",
...(projectId && { projectId }),
};
ws.send(JSON.stringify(openedMsg));
// Subscribe and send history buffer only for new subscribers.
// Skipping the buffer on re-open prevents duplicate output when
// MuxProvider re-sends open for all terminals on reconnect.
if (!subscriptions.has(subscriptionKey)) {
// Send buffered history to catch up the new subscriber
const buffer = terminalManager.getBuffer(id, projectId);
if (buffer) {
const bufferMsg: ServerMessage = {
ch: "terminal",
id,
type: "data",
data: buffer,
...(projectId && { projectId }),
};
ws.send(JSON.stringify(bufferMsg));
}
const unsub = terminalManager.subscribe(
id,
projectId,
(data) => {
const dataMsg: ServerMessage = {
ch: "terminal",
id,
type: "data",
data,
...(projectId && { projectId }),
};
if (ws.readyState === WebSocket.OPEN) {
ws.send(JSON.stringify(dataMsg));
}
},
(exitCode) => {
const exitedMsg: ServerMessage = {
ch: "terminal",
id,
type: "exited",
code: exitCode,
...(projectId && { projectId }),
};
if (ws.readyState === WebSocket.OPEN) {
ws.send(JSON.stringify(exitedMsg));
}
},
);
subscriptions.set(subscriptionKey, unsub);
}
}
} else if (type === "data" && "data" in msg) {
if (isWindows()) {
handleWindowsPipeMessage(
msg as { id: string; type: string; projectId?: string; data: string },
ws,
winPipes,
winPipeBuffers,
{ connect: netConnect, resolvePipePath },
);
} else {
terminalManager?.write(id, msg.data, projectId);
}
} else if (type === "resize" && "cols" in msg && "rows" in msg) {
if (isWindows()) {
handleWindowsPipeMessage(
msg as {
id: string;
type: string;
projectId?: string;
cols: number;
rows: number;
},
ws,
winPipes,
winPipeBuffers,
{ connect: netConnect, resolvePipePath },
);
} else {
terminalManager?.resize(id, msg.cols, msg.rows, projectId);
}
} else if (type === "close") {
if (isWindows()) {
handleWindowsPipeMessage(
msg as {
id: string;
type: string;
projectId?: string;
data?: string;
cols?: number;
rows?: number;
},
ws,
winPipes,
winPipeBuffers,
{ connect: netConnect, resolvePipePath },
);
} else {
// Unsubscribe this client only — TerminalManager is shared across
// all mux connections so we must not kill the PTY here.
const unsub = subscriptions.get(subscriptionKey);
if (unsub) {
unsub();
subscriptions.delete(subscriptionKey);
}
}
}
} catch (err) {
if (ws.readyState === WebSocket.OPEN) {
const errorMsg: ServerMessage = {
ch: "terminal",
id,
type: "error",
message: err instanceof Error ? err.message : String(err),
...(projectId && { projectId }),
};
ws.send(JSON.stringify(errorMsg));
}
}
} else if (msg.ch === "subscribe") {
if (msg.topics.includes("sessions") && !sessionUnsubscribe) {
sessionUnsubscribe = broadcaster.subscribe(
(sessions) => {
if (ws.readyState !== WebSocket.OPEN) return;
if (ws.bufferedAmount > WS_BUFFER_HIGH_WATERMARK) {
console.warn("[MuxServer] Skipping session snapshot — socket backpressured");
return;
}
const snapMsg: ServerMessage = { ch: "sessions", type: "snapshot", sessions };
ws.send(JSON.stringify(snapMsg));
},
(error) => {
if (ws.readyState !== WebSocket.OPEN) return;
const errMsg: ServerMessage = { ch: "sessions", type: "error", error };
ws.send(JSON.stringify(errMsg));
},
);
}
if (msg.topics.includes("notifications") && !notificationUnsubscribe) {
notificationUnsubscribe = notificationBroadcaster.subscribe(
(notifications, type, limit) => {
if (ws.readyState !== WebSocket.OPEN) return;
if (ws.bufferedAmount > WS_BUFFER_HIGH_WATERMARK) {
console.warn("[MuxServer] Skipping notification update — socket backpressured");
return;
}
const msg: ServerMessage = {
ch: "notifications",
type,
notifications,
limit,
};
ws.send(JSON.stringify(msg));
},
(error) => {
if (ws.readyState !== WebSocket.OPEN) return;
const errMsg: ServerMessage = { ch: "notifications", type: "error", error };
ws.send(JSON.stringify(errMsg));
},
);
}
}
} catch (err) {
console.error("[MuxServer] Failed to parse message:", err);
recordActivityEvent({
source: "ui",
kind: "ui.terminal_protocol_error",
level: "warn",
summary: "invalid mux client message — parse failed",
data: {
errorMessage: err instanceof Error ? err.message : String(err),
remoteAddr,
subscriberCount: subscriptions.size,
},
});
const errorMsg: ServerMessage = {
ch: "system",
type: "error",
message: "Invalid message format",
};
if (ws.readyState === WebSocket.OPEN) {
ws.send(JSON.stringify(errorMsg));
}
}
});
/**
* Handle connection close
*/
ws.on("close", (code, reason) => {
console.log("[MuxServer] Mux connection closed");
recordActivityEvent({
source: "ui",
kind: "ui.terminal_disconnected",
level: "info",
summary: "mux WebSocket connection closed",
data: {
code,
reason: reason?.toString("utf8") || undefined,
connectionAgeMs: Date.now() - connectedAt,
subscriberCount: subscriptions.size,
heartbeatLost: heartbeatLostEmitted,
remoteAddr,
},
});
clearInterval(heartbeatInterval);
sessionUnsubscribe?.();
sessionUnsubscribe = null;
notificationUnsubscribe?.();
notificationUnsubscribe = null;
for (const unsub of subscriptions.values()) {
unsub();
}
subscriptions.clear();
// Windows: close all open pipe sockets
for (const pipeSocket of winPipes.values()) {
pipeSocket.destroy();
}
winPipes.clear();
winPipeBuffers.clear();
});
// In the ws library, "error" is always followed by "close", so the close
// handler below handles all cleanup. Log the error here and nothing more.
ws.on("error", (err) => {
console.error("[MuxServer] WebSocket error:", err.message);
});
});
console.log("[MuxServer] Mux WebSocket server created (noServer mode)");
return wss;
}