feat(cli): add gateway start/stop/status lifecycle commands

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/cli/src/commands/gateway.ts

@@ -1,10 +1,12 @@
 import { createInterface } from 'node:readline';
-import { writeFileSync } from 'node:fs';
-import { resolve } from 'node:path';
+import { spawn } from 'node:child_process';
+import { existsSync, mkdirSync, readFileSync, unlinkSync, writeFileSync } from 'node:fs';
+import { dirname, resolve } from 'node:path';
 import type { Command } from 'commander';
 import {
   DEFAULT_LOCAL_CONFIG,
   DEFAULT_TEAM_CONFIG,
+  loadConfig,
   type MosaicConfig,
   type StorageTier,
 } from '@mosaic/config';
@@ -64,6 +66,37 @@ async function runInit(opts: { tier?: string; output: string }): Promise<void> {
   console.log('  2. Run: pnpm --filter @mosaic/gateway exec tsx src/main.ts');
 }
 
+const PID_FILE = resolve(process.cwd(), '.mosaic/gateway.pid');
+
+function writePidFile(pid: number): void {
+  const dir = dirname(PID_FILE);
+  if (!existsSync(dir)) mkdirSync(dir, { recursive: true });
+  writeFileSync(PID_FILE, String(pid));
+}
+
+function readPidFile(): number | null {
+  if (!existsSync(PID_FILE)) return null;
+  const raw = readFileSync(PID_FILE, 'utf-8').trim();
+  const pid = Number(raw);
+  return Number.isFinite(pid) ? pid : null;
+}
+
+function isProcessRunning(pid: number): boolean {
+  try {
+    process.kill(pid, 0);
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+function printConfigSummary(config: MosaicConfig): void {
+  console.log(`  Tier:    ${config.tier}`);
+  console.log(`  Storage: ${config.storage.type}`);
+  console.log(`  Queue:   ${config.queue.type}`);
+  console.log(`  Memory:  ${config.memory.type}`);
+}
+
 export function registerGatewayCommand(program: Command): void {
   const gateway = program.command('gateway').description('Gateway management commands');
 
@@ -75,4 +108,91 @@ export function registerGatewayCommand(program: Command): void {
     .action(async (opts: { tier?: string; output: string }) => {
       await runInit(opts);
     });
+
+  gateway
+    .command('start')
+    .description('Start the Mosaic gateway process')
+    .option('--port <port>', 'Port to listen on (overrides config)')
+    .option('--daemon', 'Run in background and write PID to .mosaic/gateway.pid')
+    .action((opts: { port?: string; daemon?: boolean }) => {
+      const config = loadConfig();
+      const port = opts.port ?? '4000';
+
+      console.log('Starting gateway…');
+      printConfigSummary(config);
+      console.log(`  Port:    ${port}`);
+
+      const entryPoint = resolve(process.cwd(), 'apps/gateway/src/main.ts');
+      const env = { ...process.env, GATEWAY_PORT: port };
+
+      if (opts.daemon) {
+        const child = spawn('npx', ['tsx', entryPoint], {
+          env,
+          stdio: 'ignore',
+          detached: true,
+        });
+
+        child.unref();
+
+        if (child.pid) {
+          writePidFile(child.pid);
+          console.log(`\nGateway started in background (PID ${child.pid})`);
+          console.log(`PID file: ${PID_FILE}`);
+        }
+      } else {
+        const child = spawn('npx', ['tsx', entryPoint], {
+          env,
+          stdio: 'inherit',
+        });
+
+        child.on('exit', (code) => {
+          process.exit(code ?? 0);
+        });
+      }
+    });
+
+  gateway
+    .command('stop')
+    .description('Stop the running gateway process')
+    .action(() => {
+      const pid = readPidFile();
+
+      if (pid === null) {
+        console.error('No PID file found at', PID_FILE);
+        process.exit(1);
+      }
+
+      if (!isProcessRunning(pid)) {
+        console.log(`Process ${pid} is not running. Removing stale PID file.`);
+        unlinkSync(PID_FILE);
+        return;
+      }
+
+      process.kill(pid, 'SIGTERM');
+      unlinkSync(PID_FILE);
+      console.log(`Gateway stopped (PID ${pid})`);
+    });
+
+  gateway
+    .command('status')
+    .description('Show gateway process status')
+    .action(() => {
+      const config = loadConfig();
+      const pid = readPidFile();
+
+      if (pid !== null && isProcessRunning(pid)) {
+        console.log('Gateway: running');
+        console.log(`  PID:     ${pid}`);
+      } else {
+        console.log('Gateway: stopped');
+        if (pid !== null) {
+          console.log(`  (stale PID file for ${pid})`);
+          unlinkSync(PID_FILE);
+        }
+      }
+
+      console.log('');
+      console.log('Config:');
+      printConfigSummary(config);
+    });
 }