import { spawn } from "node:child_process";
import { getDefaultTimeoutMs, getMaxOutputBytes } from "../config.js";
import { logError, logResponse } from "../logger/index.js";
import type { RuntimeLogContext } from "../types.js";
export function runCli(
command: string,
args: string[],
timeoutMs = getDefaultTimeoutMs(),
cwd?: string,
logContext?: RuntimeLogContext,
): Promise<string> {
return new Promise((resolve, reject) => {
const startedAt = Date.now();
const child = spawn(command, args, {
stdio: ["ignore", "pipe", "pipe"],
cwd,
env: {
...process.env,
NO_COLOR: "1",
FORCE_COLOR: "0",
TERM: "dumb",
},
});
let stdout = "";
let stderr = "";
let totalOutputBytes = 0;
let settled = false;
const maxOutputBytes = getMaxOutputBytes();
const outputLimitMessage = `${command} output exceeded MCP_MAX_OUTPUT_BYTES=${maxOutputBytes} bytes`;
const appendChunk = (target: "stdout" | "stderr", chunk: Buffer): boolean => {
const remaining = maxOutputBytes - totalOutputBytes;
if (remaining <= 0) {
return true;
}
if (chunk.length <= remaining) {
const text = chunk.toString();
if (target === "stdout") {
stdout += text;
} else {
stderr += text;
}
totalOutputBytes += chunk.length;
return false;
}
const clipped = chunk.subarray(0, remaining).toString();
if (target === "stdout") {
stdout += clipped;
} else {
stderr += clipped;
}
totalOutputBytes += remaining;
return true;
};
const rejectWithLog = (errorCode: string, message: string, stderrText?: string): void => {
if (settled) {
return;
}
settled = true;
clearTimeout(timer);
if (logContext) {
logError({
context: logContext,
durationMs: Date.now() - startedAt,
errorCode,
errorMessage: message,
stderr: stderrText ?? stderr,
});
}
reject(new Error(message));
};
const resolveWithLog = (): void => {
if (settled) {
return;
}
settled = true;
clearTimeout(timer);
if (logContext) {
logResponse({
context: logContext,
durationMs: Date.now() - startedAt,
exitCode: 0,
stdout,
stderr,
truncated: false,
});
}
resolve(stdout.trim() || "(empty response)");
};
const timer = setTimeout(() => {
try {
child.kill("SIGTERM");
} catch {
}
rejectWithLog("CLI_TIMEOUT", `${command} timed out after ${timeoutMs}ms`);
}, timeoutMs);
child.stdout.on("data", (chunk: Buffer) => {
const exceeded = appendChunk("stdout", chunk);
if (!exceeded) {
return;
}
try {
child.kill("SIGTERM");
} catch {
}
rejectWithLog("CLI_OUTPUT_LIMIT_EXCEEDED", outputLimitMessage, stderr);
});
child.stderr.on("data", (chunk: Buffer) => {
const exceeded = appendChunk("stderr", chunk);
if (!exceeded) {
return;
}
try {
child.kill("SIGTERM");
} catch {
}
rejectWithLog("CLI_OUTPUT_LIMIT_EXCEEDED", outputLimitMessage, stderr);
});
child.on("error", (error) => {
const errno = error as NodeJS.ErrnoException;
const errorCode = errno.code === "ENOENT" ? "CLI_NOT_FOUND" : "CLI_SPAWN_ERROR";
rejectWithLog(errorCode, `${command} failed to start: ${error.message}`);
});
child.on("close", (code) => {
if (code === 0) {
resolveWithLog();
return;
}
rejectWithLog(
"CLI_NON_ZERO_EXIT",
`${command} exited with code ${code}: ${stderr.trim() || "no stderr"}`,
);
});
});
}
