LocalStack MCP Server

import { spawn, SpawnOptions } from "child_process"; import { DEFAULT_COMMAND_TIMEOUT, DEFAULT_COMMAND_MAX_BUFFER } from "./config"; export interface CommandResult { stdout: string; stderr: string; error?: Error; exitCode: number | null; } export interface CommandOptions extends SpawnOptions { timeout?: number; maxBuffer?: number; onData?: (chunk: string, type: "stdout" | "stderr") => void; } export function runCommand( command: string, args: string[], options: CommandOptions = {} ): Promise<CommandResult> { return new Promise((resolve) => { const { timeout = DEFAULT_COMMAND_TIMEOUT, maxBuffer = DEFAULT_COMMAND_MAX_BUFFER, onData, ...spawnOptions } = options; const child = spawn(command, args, { ...spawnOptions }); let stdout = ""; let stderr = ""; let outBytes = 0; let errBytes = 0; let timedOut = false; let bufferExceeded = false; let error: Error | undefined; const killProcess = (reason: string) => { if (child.killed) return; error = new Error(reason); child.kill(spawnOptions.killSignal ?? "SIGTERM"); setTimeout(() => { if (!child.killed) child.kill("SIGKILL"); }, 2000); }; const timer = setTimeout(() => { timedOut = true; killProcess(`Command timed out after ${timeout}ms`); }, timeout); const onChunk = (isStdout: boolean) => (chunk: Buffer) => { if (timedOut || bufferExceeded) return; const len = chunk.length; if (isStdout) { outBytes += len; const data = chunk.toString(); stdout += data; if (onData) onData(data, "stdout"); if (outBytes > maxBuffer) { bufferExceeded = true; killProcess(`stdout exceeded maxBuffer size of ${maxBuffer} bytes`); } } else { errBytes += len; const data = chunk.toString(); stderr += data; if (onData) onData(data, "stderr"); if (errBytes > maxBuffer) { bufferExceeded = true; killProcess(`stderr exceeded maxBuffer size of ${maxBuffer} bytes`); } } }; child.stdout?.on("data", onChunk(true)); child.stderr?.on("data", onChunk(false)); child.on("error", (err) => { error = err; }); child.on("close", (code) => { clearTimeout(timer); if (!timedOut && !bufferExceeded && code !== 0 && !error) { error = new Error(`Command failed with exit code ${code}: ${stderr.trim()}`); } resolve({ stdout, stderr, error, exitCode: code }); }); }); } export function stripAnsiCodes(text: string): string { return text.replace(/\x1b\[[0-9;]*[a-zA-Z]/g, ""); }