feat(deploy): 画布 Agent - 独立 yingce-agent 容器并修复运行中断

生产会话不再因 stdout 管道提前关闭被误判失败。设置 YINGCE_AGENT_URL 后只走独立容器，失败不回退到内嵌进程。

yingce-agent/server.mjs

@@ -0,0 +1,167 @@
+import { spawn } from "node:child_process";
+import { timingSafeEqual } from "node:crypto";
+import { createServer } from "node:http";
+import { dirname } from "node:path";
+
+const token = process.env.YINGCE_AGENT_TOKEN || "";
+const maxSessions = positiveInt(process.env.MAX_CONCURRENT_SESSIONS, 8, 1000);
+const memoryMB = positiveInt(process.env.NODE_MAX_OLD_SPACE_SIZE, 512, 8192);
+const runtimePath = process.env.YINGCE_AGENT_RUNTIME || "/app/agent-runtime/agent-runtime.mjs";
+const port = Number(process.env.PORT || 8081);
+const bodyLimit = 32 * 1024 * 1024;
+
+if (token.length < 32) {
+  console.error("YINGCE_AGENT_TOKEN must contain at least 32 characters");
+  process.exit(1);
+}
+
+let active = 0;
+const waiters = [];
+
+function positiveInt(raw, fallback, max) {
+  const parsed = Number(raw);
+  if (!Number.isInteger(parsed) || parsed < 1) return fallback;
+  return Math.min(parsed, max);
+}
+
+function authorized(request) {
+  const actual = Buffer.from(request.headers.authorization || "");
+  const expected = Buffer.from(`Bearer ${token}`);
+  return actual.length === expected.length && timingSafeEqual(actual, expected);
+}
+
+function acquire(request) {
+  if (active < maxSessions) {
+    active += 1;
+    return Promise.resolve();
+  }
+  return new Promise((resolve, reject) => {
+    const waiter = { resolve, reject };
+    waiters.push(waiter);
+    const abort = () => {
+      const index = waiters.indexOf(waiter);
+      if (index >= 0) waiters.splice(index, 1);
+      reject(new Error("Agent request cancelled while queued"));
+    };
+    if (request.aborted || request.destroyed) abort();
+    else request.once("aborted", abort);
+  });
+}
+
+function release() {
+  const waiter = waiters.shift();
+  if (waiter) {
+    waiter.resolve();
+    return;
+  }
+  active = Math.max(0, active - 1);
+}
+
+function readBody(request) {
+  return new Promise((resolve, reject) => {
+    const chunks = [];
+    let size = 0;
+    request.on("data", (chunk) => {
+      size += chunk.length;
+      if (size > bodyLimit) {
+        reject(new Error("request body too large"));
+        request.destroy();
+        return;
+      }
+      chunks.push(chunk);
+    });
+    request.on("end", () => resolve(Buffer.concat(chunks)));
+    request.on("error", reject);
+  });
+}
+
+function writeRuntimeError(response, message) {
+  if (!response.headersSent) {
+    response.writeHead(200, { "content-type": "application/x-ndjson" });
+  }
+  response.end(`${JSON.stringify({ event: "runtime_error", message })}\n`);
+}
+
+const server = createServer(async (request, response) => {
+  if (request.method === "GET" && request.url === "/healthz") {
+    response.writeHead(200, { "content-type": "application/json" });
+    response.end(JSON.stringify({ ok: true, active, limit: maxSessions }));
+    return;
+  }
+  if (request.method !== "POST" || request.url !== "/v1/runs") {
+    response.writeHead(404, { "content-type": "application/json" });
+    response.end(JSON.stringify({ error: "not found" }));
+    return;
+  }
+  if (!authorized(request)) {
+    response.writeHead(401, { "content-type": "application/json" });
+    response.end(JSON.stringify({ error: "unauthorized" }));
+    return;
+  }
+  let body;
+  try {
+    body = await readBody(request);
+    JSON.parse(body.toString("utf8"));
+  } catch (error) {
+    response.writeHead(400, { "content-type": "application/json" });
+    response.end(JSON.stringify({ error: error instanceof Error ? error.message : "invalid request" }));
+    return;
+  }
+  try {
+    await acquire(request);
+  } catch (error) {
+    response.writeHead(499, { "content-type": "application/json" });
+    response.end(JSON.stringify({ error: error instanceof Error ? error.message : "cancelled" }));
+    return;
+  }
+
+  const child = spawn(process.execPath, [`--max-old-space-size=${memoryMB}`, runtimePath], {
+    cwd: dirname(runtimePath),
+    env: {
+      PATH: process.env.PATH || "",
+      NODE_ENV: "production",
+      PI_OFFLINE: "1",
+    },
+    stdio: ["pipe", "pipe", "pipe"],
+  });
+  let released = false;
+  const finish = () => {
+    if (released) return;
+    released = true;
+    release();
+  };
+  let sawRuntimeError = false;
+  const stop = () => {
+    if (child.exitCode === null && child.signalCode === null) child.kill("SIGTERM");
+  };
+  request.on("aborted", stop);
+  response.writeHead(200, { "content-type": "application/x-ndjson" });
+  child.stdout.on("data", (chunk) => {
+    const text = chunk.toString("utf8");
+    if (text.includes('"runtime_error"') || text.includes('"bridge_error"')) sawRuntimeError = true;
+    response.write(chunk);
+  });
+  child.stderr.on("data", (chunk) => process.stderr.write(chunk));
+  child.on("error", (error) => {
+    writeRuntimeError(response, error.message);
+    finish();
+  });
+  child.on("close", (code) => {
+    if (!response.writableEnded) {
+      if (code && !sawRuntimeError) {
+        response.write(`${JSON.stringify({ event: "runtime_error", message: `Agent runtime exited with code ${code}` })}\n`);
+      }
+      response.end();
+    }
+    finish();
+  });
+  child.stdin.end(body);
+});
+
+server.requestTimeout = 0;
+server.headersTimeout = 0;
+server.timeout = 0;
+server.listen(port, "0.0.0.0", () => {
+  const address = server.address();
+  console.log(`YINGCE_AGENT_READY ${address.port}`);
+});