Merge pull request #39 from kaifcoder/feature/unified-hotreload

Feature/unified hotreload

Author: kaifcoder

README.md

@@ -53,6 +53,7 @@ Building a production-style polyglot microservice environment normally requires
 Use it to prototype architectures, onboard teams faster, or spin up reproducible demos / PoCs.
 
 ## Features
+
 - 🚀 Rapid polyglot monorepo scaffolding (Node.js, Python/FastAPI, Go, Java Spring Boot, Next.js)
 - 🧩 Optional presets: Turborepo, Nx, or Basic runner
 - 🐳 Automatic Dockerfile + Docker Compose generation
@@ -61,6 +62,7 @@ Use it to prototype architectures, onboard teams faster, or spin up reproducible
 - 📦 Shared package (`packages/shared`) for cross-service JS utilities
 - 🧪 Vitest test setup for the CLI itself
 - 🌈 Colorized dev logs & health probing for Node/frontend services
+- 🔥 Unified hot reload aggregator (`create-polyglot hot`) for Node, Next.js, Python (uvicorn), Go, and Java (Spring Boot)
 - 🔌 Plugin skeleton generation (`create-polyglot add plugin <name>`)
 - 📄 Single source of truth: `polyglot.json`
 - ✅ Safe guards: port collision checks, reserved name checks, graceful fallbacks
@@ -69,6 +71,7 @@ Use it to prototype architectures, onboard teams faster, or spin up reproducible
 ## Quick Start
 Scaffold a workspace named `my-org` with multiple services:
 
+| `create-polyglot hot [--services <subset>] [--dry-run]` | Unified hot reload (restart / HMR) across services. |
 ```bash
 npx create-polyglot init my-org -s node,python,go,java,frontend --git --yes
 ```
@@ -77,6 +80,20 @@ Then run everything (Node + frontend locally):
 ```bash
 create-polyglot dev
 ```
+Unified hot reload (auto restart / HMR):
+```bash
+create-polyglot hot
+```
+
+Dry run (see what would execute without starting processes):
+```bash
+create-polyglot hot --dry-run
+```
+
+Limit to a subset (by names or types):
+```bash
+create-polyglot hot --services node,python
+```
 
 Or via Docker Compose:
 ```bash

bin/index.js

@@ -8,6 +8,7 @@ import path from 'path';
 import { renderServicesTable } from './lib/ui.js';
 import { runDev } from './lib/dev.js';
 import { startAdminDashboard } from './lib/admin.js';
+import { runHotReload } from './lib/hotreload.js';
 
 const program = new Command();
 
@@ -164,6 +165,22 @@ program
       process.exit(1);
     }
   });
+
+// Unified hot reload aggregator
+program
+  .command('hot')
+  .description('Unified hot reload across services (auto-restart / HMR)')
+  .option('-s, --services <list>', 'Subset of services (comma names or types)')
+  .option('--dry-run', 'Show what would run without starting processes')
+  .action(async (opts) => {
+    try {
+      const filter = opts.services ? opts.services.split(',').map(s => s.trim()).filter(Boolean) : [];
+      await runHotReload({ servicesFilter: filter, dryRun: !!opts.dryRun });
+    } catch (e) {
+      console.error(chalk.red('Failed to start hot reload:'), e.message);
+      process.exit(1);
+    }
+  });
 
 program.parse();
 

bin/lib/hotreload.js

@@ -0,0 +1,226 @@
+import fs from 'fs';
+import path from 'path';
+import { spawn } from 'node:child_process';
+import chalk from 'chalk';
+
+/*
+ Unified Hot Reload Aggregator
+ ----------------------------
+ Goal: Provide a single command that watches source files for all supported
+ service types and restarts their dev process (or equivalent) on changes.
+
+ Supported service types & strategy:
+ - node: restart on .js/.mjs/.cjs/.ts changes inside service dir (excluding node_modules).
+         If service has dev script using nodemon/ts-node-dev already, we just run it.
+ - frontend (Next.js): rely on next dev internal HMR (no restart). We'll watch config files
+         (next.config.*, .env*) and trigger a manual restart if they change.
+ - python (FastAPI): use uvicorn with --reload if available; if requirements specify uvicorn,
+         we spawn `uvicorn app.main:app --reload --port <port>` instead of existing dev script.
+ - go: detect main.go; use `go run .` and restart on .go file changes.
+ - java (Spring Boot): use `mvn spring-boot:run` and restart on changes to src/ (requires JDK & Maven).
+       For performance we debounce restarts.
+
+ Edge cases:
+ - Missing runtime tool (e.g., mvn not installed) -> warn and skip hot reload for that service.
+ - Large flurries of changes -> debounce restart (default 400ms).
+ - Service without supported pattern -> skip with yellow message.
+
+ Exposed function: runHotReload({ servicesFilter, dryRun })
+ */
+
+const DEBOUNCE_MS = 400;
+
+function colorFor(name) {
+  const colors = [chalk.cyan, chalk.magenta, chalk.green, chalk.blue, chalk.yellow, chalk.redBright];
+  let sum = 0; for (let i=0;i<name.length;i++) sum += name.charCodeAt(i);
+  return colors[sum % colors.length];
+}
+
+export async function runHotReload({ servicesFilter = [], dryRun = false } = {}) {
+  const cwd = process.cwd();
+  const cfgPath = path.join(cwd, 'polyglot.json');
+  if (!fs.existsSync(cfgPath)) {
+    console.error(chalk.red('polyglot.json not found. Run inside a generated workspace.'));
+    process.exit(1);
+  }
+  const cfg = JSON.parse(fs.readFileSync(cfgPath, 'utf-8'));
+  let services = cfg.services || [];
+  if (servicesFilter.length) {
+    const filterSet = new Set(servicesFilter);
+    services = services.filter(s => filterSet.has(s.name) || filterSet.has(s.type));
+  }
+  if (!services.length) {
+    console.log(chalk.yellow('No matching services for hot reload.'));
+    return;
+  }
+
+  console.log(chalk.cyan(`\n🔥 Unified hot reload starting (${services.length} services)...`));
+
+  const watchers = [];
+  const processes = new Map();
+
+  function spawnService(svc) {
+    const svcPath = path.join(cwd, svc.path);
+    if (!fs.existsSync(svcPath)) {
+      console.log(chalk.yellow(`Skipping ${svc.name} (path missing)`));
+      return;
+    }
+    const color = colorFor(svc.name);
+    let cmd, args, watchGlobs, restartStrategy;
+    switch (svc.type) {
+      case 'node': {
+        const pkgPath = path.join(svcPath, 'package.json');
+        if (!fs.existsSync(pkgPath)) { console.log(chalk.yellow(`Skipping ${svc.name} (no package.json)`)); return; }
+        let pkg; try { pkg = JSON.parse(fs.readFileSync(pkgPath,'utf-8')); } catch { console.log(chalk.yellow(`Skipping ${svc.name} (invalid package.json)`)); return; }
+        const script = pkg.scripts?.dev || pkg.scripts?.start;
+        if (!script) { console.log(chalk.yellow(`Skipping ${svc.name} (no dev/start script)`)); return; }
+        // Prefer existing nodemon usage; else run node and restart manually.
+        const usesNodemon = /nodemon/.test(script);
+        if (usesNodemon) {
+          cmd = detectPM(svcPath);
+          args = ['run', pkg.scripts.dev ? 'dev' : 'start'];
+          watchGlobs = []; // nodemon handles its own watching
+          restartStrategy = 'internal';
+        } else {
+          cmd = detectPM(svcPath);
+          args = ['run', pkg.scripts.dev ? 'dev' : 'start'];
+          watchGlobs = ['**/*.js','**/*.mjs','**/*.cjs','**/*.ts','!node_modules/**'];
+          restartStrategy = 'respawn';
+        }
+        break;
+      }
+      case 'frontend': {
+        // Next.js handles HMR internally; only restart if config changes.
+        cmd = detectPM(svcPath); args = ['run','dev'];
+        watchGlobs = ['next.config.*','*.env','*.env.*'];
+        restartStrategy = 'internal+config-restart';
+        break;
+      }
+      case 'python': {
+        // Use uvicorn --reload directly if possible.
+        cmd = 'uvicorn';
+        args = ['app.main:app','--reload','--port', String(svc.port)];
+        watchGlobs = ['app/**/*.py','*.py'];
+        restartStrategy = 'respawn';
+        break;
+      }
+      case 'go': {
+        cmd = 'go'; args = ['run','.'];
+        watchGlobs = ['**/*.go'];
+        restartStrategy = 'respawn';
+        break;
+      }
+      case 'java': {
+        // Spring Boot dev run; restart on src changes.
+        cmd = 'mvn'; args = ['spring-boot:run'];
+        watchGlobs = ['src/main/java/**/*.java','src/main/resources/**/*'];
+        restartStrategy = 'respawn';
+        break;
+      }
+      default:
+        console.log(chalk.yellow(`Skipping ${svc.name} (unsupported type ${svc.type})`));
+        return;
+    }
+
+    if (dryRun) {
+      console.log(chalk.gray(`[dry-run] ${svc.name}: ${cmd} ${args.join(' ')} (${restartStrategy})`));
+      return;
+    }
+
+    const child = spawn(cmd, args, { cwd: svcPath, env: { ...process.env, PORT: String(svc.port) }, shell: true });
+    processes.set(svc.name, { child, svc, watchGlobs, restartStrategy, svcPath });
+    child.stdout.on('data', d => process.stdout.write(color(`[${svc.name}] `) + d.toString()));
+    child.stderr.on('data', d => process.stderr.write(color(`[${svc.name}] `) + d.toString()));
+    child.on('exit', code => {
+      process.stdout.write(color(`[${svc.name}] exited (${code})`)+"\n");
+    });
+
+    if (watchGlobs && watchGlobs.length) {
+      // Minimal glob watching without external deps: recursive fs watch + filter.
+      // NOTE: macOS recursive watch limitations; we manually walk tree initially.
+      const fileList = listFilesRecursive(svcPath);
+      const matcher = buildMatcher(watchGlobs);
+      const pending = { timeout: null };
+
+      function scheduleRestart() {
+        if (pending.timeout) clearTimeout(pending.timeout);
+        pending.timeout = setTimeout(() => {
+          const meta = processes.get(svc.name);
+          if (!meta) return;
+          console.log(color(`↻ Restarting ${svc.name} due to changes...`));
+          meta.child.kill('SIGINT');
+          spawnService(svc); // respawn fresh
+        }, DEBOUNCE_MS);
+      }
+
+      // Initial watchers per directory
+      const dirs = new Set(fileList.map(f => path.dirname(f)));
+      for (const dir of dirs) {
+        try {
+          const w = fs.watch(dir, { persistent: true }, (evt, fileName) => {
+            if (!fileName) return;
+            const rel = path.relative(svcPath, path.join(dir, fileName));
+            if (matcher(rel)) {
+              scheduleRestart();
+            }
+          });
+          watchers.push(w);
+        } catch {}
+      }
+    }
+  }
+
+  // Spawn all initially
+  for (const svc of services) spawnService(svc);
+
+  if (!dryRun) {
+    console.log(chalk.blue('Hot reload active. Press Ctrl+C to exit.'));
+    process.on('SIGINT', () => {
+      for (const { child } of processes.values()) child.kill('SIGINT');
+      for (const w of watchers) try { w.close(); } catch {}
+      process.exit(0);
+    });
+  }
+}
+
+function listFilesRecursive(root) {
+  const out = [];
+  function walk(p) {
+    let stats; try { stats = fs.statSync(p); } catch { return; }
+    if (stats.isDirectory()) {
+      const entries = fs.readdirSync(p);
+      for (const e of entries) walk(path.join(p, e));
+    } else {
+      out.push(p);
+    }
+  }
+  walk(root);
+  return out;
+}
+
+// Very small glob matcher supporting *, **, suffix patterns and exclusion !prefix.
+function buildMatcher(globs) {
+  const positives = globs.filter(g => !g.startsWith('!'));
+  const negatives = globs.filter(g => g.startsWith('!')).map(g => g.slice(1));
+  return rel => {
+    if (negatives.some(n => minimatchBasic(rel, n))) return false;
+    return positives.some(p => minimatchBasic(rel, p));
+  };
+}
+
+function minimatchBasic(rel, pattern) {
+  // Convert pattern to regex roughly; handle **/, *, and dotfiles.
+  let regex = pattern
+    .replace(/[.+^${}()|\-]/g, r => `\\${r}`)
+    .replace(/\\\*\*\//g, '(?:.+/)?') // /**/ style
+    .replace(/\*\*/g, '.*')
+    .replace(/\*/g, '[^/]*');
+  return new RegExp(`^${regex}$`).test(rel);
+}
+
+function detectPM(root) {
+  if (fs.existsSync(path.join(root,'pnpm-lock.yaml'))) return 'pnpm';
+  if (fs.existsSync(path.join(root,'yarn.lock'))) return 'yarn';
+  if (fs.existsSync(path.join(root,'bun.lockb'))) return 'bun';
+  return 'npm';
+}