#!/usr/bin/env node
import { spawn, ChildProcess } from "child_process";
import chokidar, { FSWatcher } from "chokidar";
import { parseArgs, buildCommand } from "./parse-args.js";
import type { WrapperOptions } from './types.js';
class ServerWrapper {
private serverProcess: ChildProcess | null;
private isRestarting: boolean;
private includePatterns: string[];
private command: string;
private commandArgs: string[];
private isDirty: boolean;
private watchers: FSWatcher[];
constructor(options: WrapperOptions) {
this.serverProcess = null;
this.isRestarting = false;
this.includePatterns = options.includePatterns || [];
this.command = options.command;
this.commandArgs = options.commandArgs;
this.isDirty = false;
this.watchers = [];
}
start(): void {
console.error("[Wrapper] Starting MCP server...");
console.error(`[Wrapper] Command: ${this.command} ${this.commandArgs.join(' ')}`);
if (this.includePatterns.length > 0) {
console.error(`[Wrapper] Include patterns: ${this.includePatterns.join(', ')}`);
}
// Set environment variable for include patterns
const env = { ...process.env };
if (this.includePatterns.length > 0) {
env.MCP_HOT_RELOAD_INCLUDE = this.includePatterns.join(',');
}
this.serverProcess = spawn(this.command, this.commandArgs, {
stdio: ["inherit", "inherit", "pipe"],
env: env
});
// Monitor stderr for dirty notifications
this.serverProcess.stderr?.on("data", (data: Buffer) => {
const message = data.toString();
process.stderr.write(message);
// Check for dirty state from the server
if (message.includes("marking server as dirty") && !this.isRestarting) {
this.isDirty = true;
console.error("[Wrapper] Server marked as dirty, scheduling restart...");
setTimeout(() => this.restart(), 1000); // Delay to batch multiple changes
}
});
this.serverProcess.on("exit", (code, signal) => {
if (!this.isRestarting) {
console.error(`[Wrapper] Server exited with code ${code}, signal ${signal}`);
process.exit(code || 0);
}
});
this.serverProcess.on("error", (err) => {
console.error("[Wrapper] Server process error:", err);
process.exit(1);
});
}
startWatching(): void {
// Set up file watchers for include patterns
if (this.includePatterns.length > 0) {
console.error("[Wrapper] Setting up file watchers for include patterns");
const watcher = chokidar.watch(this.includePatterns, {
persistent: true,
ignoreInitial: true,
cwd: process.cwd()
});
watcher.on("all", (event, path) => {
if (!this.isDirty && !this.isRestarting) {
console.error(`[Wrapper] Include file ${event}: ${path}, marking for restart`);
this.isDirty = true;
setTimeout(() => this.restart(), 1000); // Delay to batch multiple changes
}
});
this.watchers.push(watcher);
}
}
async restart(): Promise<void> {
if (this.isRestarting || !this.isDirty) return;
this.isRestarting = true;
this.isDirty = false;
console.error("[Wrapper] Restarting server...");
// Kill the current process
if (this.serverProcess) {
this.serverProcess.kill("SIGTERM");
// Wait for process to exit
await new Promise<void>((resolve) => {
this.serverProcess!.on("exit", resolve);
// Force kill after timeout
setTimeout(() => {
if (this.serverProcess && this.serverProcess.exitCode === null) {
this.serverProcess.kill("SIGKILL");
}
}, 5000);
});
}
// Start new process
this.isRestarting = false;
this.start();
}
async stop(): Promise<void> {
// Close all watchers
for (const watcher of this.watchers) {
await watcher.close();
}
// Kill server process
if (this.serverProcess) {
this.serverProcess.kill("SIGTERM");
}
}
}
// Global wrapper instance for signal handlers
let wrapper: ServerWrapper | null = null;
// Handle signals
process.on("SIGINT", async () => {
console.error("[Wrapper] Received SIGINT, shutting down...");
if (wrapper) {
await wrapper.stop();
}
process.exit(0);
});
process.on("SIGTERM", async () => {
console.error("[Wrapper] Received SIGTERM, shutting down...");
if (wrapper) {
await wrapper.stop();
}
process.exit(0);
});
// Parse command line arguments
const args = process.argv.slice(2);
const parsedArgs = parseArgs(args);
const { command, args: commandArgs } = buildCommand(parsedArgs);
// Start the wrapper
wrapper = new ServerWrapper({
includePatterns: parsedArgs.includePatterns,
command,
commandArgs
});
wrapper.start();
wrapper.startWatching();
