Files
harness-tools/extensions/_workflows/sandbox.ts
T
2026-08-24 16:33:11 -04:00

300 lines
9.3 KiB
TypeScript

import { randomBytes } from "node:crypto";
import { spawn, type ChildProcess } from "node:child_process";
import * as path from "node:path";
import { fileURLToPath } from "node:url";
import { safeStringify, toSerializable } from "./serialization.ts";
const MAX_SOURCE_BYTES = 512 * 1024;
const MAX_ARGS_BYTES = 256 * 1024;
const MAX_RESULT_BYTES = 1024 * 1024;
const MAX_AGENT_MESSAGE_BYTES = 512 * 1024;
const MAX_AGENT_REQUESTS = 32;
export interface SandboxAgentOptions {
label?: unknown;
phase?: unknown;
schema?: unknown;
model?: unknown;
provider?: unknown;
effort?: unknown;
}
export interface SandboxAgentResult {
ok: boolean;
output: string;
structured?: unknown;
error?: string;
}
export interface RunWorkflowSandboxOptions {
source: string;
args: unknown;
cwd: string;
signal: AbortSignal;
onAgent: (
prompt: string,
options: SandboxAgentOptions,
signal: AbortSignal,
) => Promise<SandboxAgentResult>;
onPhase: (title: string) => void;
}
function byteLength(value: string) {
return Buffer.byteLength(value, "utf8");
}
function isRecord(value: unknown): value is Record<string, unknown> {
return typeof value === "object" && value !== null && !Array.isArray(value);
}
function errorText(error: unknown) {
return error instanceof Error ? error.message : String(error);
}
function terminateChild(child: ChildProcess) {
if (child.exitCode !== null || child.signalCode !== null) return;
child.kill("SIGTERM");
const force = setTimeout(() => {
if (child.exitCode === null && child.signalCode === null)
child.kill("SIGKILL");
}, 1_000);
force.unref?.();
}
function sanitizeAgentOptions(value: unknown): SandboxAgentOptions {
if (!isRecord(value)) return {};
return {
...(value.label !== undefined ? { label: value.label } : {}),
...(value.phase !== undefined ? { phase: value.phase } : {}),
...(value.schema !== undefined ? { schema: value.schema } : {}),
...(value.model !== undefined ? { model: value.model } : {}),
...(value.provider !== undefined ? { provider: value.provider } : {}),
...(value.effort !== undefined ? { effort: value.effort } : {}),
};
}
/**
* Execute orchestration code in a separate, permission-restricted Node process.
* The child can only invoke the narrow agent/phase IPC protocol and is always
* terminated on completion, cancellation, or protocol failure. The workflow
* itself and its agent requests have no wall-clock deadline. Active requests
* are aborted only when the workflow is cancelled or the sandbox is cleaned up.
*/
export function runWorkflowSandbox(options: RunWorkflowSandboxOptions) {
if (!process.allowedNodeEnvironmentFlags.has("--permission")) {
return Promise.reject(
new Error("This Node runtime cannot enforce workflow child permissions"),
);
}
if (byteLength(options.source) > MAX_SOURCE_BYTES) {
return Promise.reject(
new Error(`Workflow script exceeds the ${MAX_SOURCE_BYTES} byte limit`),
);
}
const argsJson = safeStringify(
{ defined: options.args !== undefined, value: options.args },
{ maxBytes: MAX_ARGS_BYTES, maxDepth: 16, maxNodes: 10_000 },
);
if (byteLength(argsJson) > MAX_ARGS_BYTES) {
return Promise.reject(new Error("Workflow args exceed the IPC limit"));
}
return new Promise<unknown>((resolve, reject) => {
const workerPath = fileURLToPath(
new URL("./sandbox-child.cjs", import.meta.url),
);
const child = spawn(
process.execPath,
[
"--permission",
`--allow-fs-read=${path.dirname(workerPath)}`,
"--max-old-space-size=128",
"--stack-size=2048",
workerPath,
],
{
cwd: options.cwd,
env: {
PATH: process.env.PATH ?? "",
NODE_NO_WARNINGS: "1",
},
stdio: ["ignore", "ignore", "ignore", "ipc"],
},
);
const token = randomBytes(24).toString("hex");
const requestIds = new Set<number>();
const activeAgentRequests = new Map<number, AbortController>();
let requestCount = 0;
let finished = false;
const cleanup = () => {
for (const abortController of activeAgentRequests.values()) {
abortController.abort(new Error("Workflow stopped"));
}
activeAgentRequests.clear();
options.signal.removeEventListener("abort", onAbort);
child.removeAllListeners("message");
child.removeAllListeners("error");
child.removeAllListeners("exit");
terminateChild(child);
};
const finish = (error?: Error, value?: unknown) => {
if (finished) return;
finished = true;
cleanup();
if (error) reject(error);
else resolve(value);
};
const onAbort = () => finish(new Error("Workflow was aborted"));
options.signal.addEventListener("abort", onAbort, { once: true });
if (options.signal.aborted) {
onAbort();
return;
}
child.on("error", (error) => finish(error));
child.on("exit", (code, exitSignal) => {
if (!finished) {
finish(
new Error(
`Workflow sandbox exited before completion (${exitSignal ?? code ?? "unknown"})`,
),
);
}
});
child.on("message", (raw: unknown) => {
if (
!isRecord(raw) ||
raw.token !== token ||
typeof raw.kind !== "string"
) {
finish(new Error("Workflow sandbox sent an invalid IPC message"));
return;
}
if (raw.kind === "phase") {
if (
typeof raw.payloadJson !== "string" ||
byteLength(raw.payloadJson) > 4096
) {
finish(new Error("Workflow sandbox sent an invalid phase update"));
return;
}
try {
const payload: unknown = JSON.parse(raw.payloadJson);
if (!isRecord(payload) || typeof payload.title !== "string") {
throw new Error("invalid title");
}
options.onPhase(payload.title.slice(0, 160));
} catch {
finish(new Error("Workflow sandbox sent an invalid phase update"));
}
return;
}
if (raw.kind === "agent") {
if (
typeof raw.payloadJson !== "string" ||
byteLength(raw.payloadJson) > MAX_AGENT_MESSAGE_BYTES
) {
finish(new Error("Workflow sandbox sent an oversized agent request"));
return;
}
let payload: unknown;
try {
payload = JSON.parse(raw.payloadJson);
} catch {
finish(new Error("Workflow sandbox sent malformed agent JSON"));
return;
}
if (
!isRecord(payload) ||
!Number.isSafeInteger(payload.id) ||
typeof payload.id !== "number" ||
payload.id < 1 ||
typeof payload.prompt !== "string" ||
payload.prompt.length > 100_000 ||
!isRecord(payload.options)
) {
finish(new Error("Workflow sandbox sent an invalid agent request"));
return;
}
if (requestIds.has(payload.id) || ++requestCount > MAX_AGENT_REQUESTS) {
finish(
new Error("Workflow sandbox exceeded its agent request budget"),
);
return;
}
requestIds.add(payload.id);
const id = payload.id;
const abortController = new AbortController();
const sendResult = (result: SandboxAgentResult) => {
if (!activeAgentRequests.delete(id)) return;
if (finished || !child.connected) return;
const normalized = toSerializable(result, {
maxDepth: 16,
maxNodes: 10_000,
maxStringBytes: 128 * 1024,
});
let resultJson = JSON.stringify(normalized);
if (byteLength(resultJson) > MAX_AGENT_MESSAGE_BYTES) {
resultJson = JSON.stringify({
ok: false,
output: "",
error: "Agent result exceeded the workflow IPC output limit",
});
}
child.send({ token, kind: "agentResult", id, resultJson });
};
activeAgentRequests.set(id, abortController);
void options
.onAgent(
payload.prompt,
sanitizeAgentOptions(payload.options),
abortController.signal,
)
.then(sendResult)
.catch((error) =>
sendResult({ ok: false, output: "", error: errorText(error) }),
);
return;
}
if (raw.kind === "result") {
if (
typeof raw.resultJson !== "string" ||
byteLength(raw.resultJson) > MAX_RESULT_BYTES
) {
finish(new Error("Workflow result exceeded the IPC limit"));
return;
}
try {
const normalized = toSerializable(JSON.parse(raw.resultJson));
finish(undefined, JSON.parse(JSON.stringify(normalized)));
} catch (error) {
finish(
new Error(`Workflow returned invalid JSON: ${errorText(error)}`),
);
}
return;
}
if (raw.kind === "error" && typeof raw.error === "string") {
finish(new Error(raw.error.slice(0, 16 * 1024)));
return;
}
finish(new Error("Workflow sandbox sent an unknown IPC message"));
});
child.send(
{
kind: "init",
token,
source: options.source,
argsJson,
},
(error) => {
if (error) finish(error);
},
);
});
}