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fix: harden SSR server with keepalive fix, error handling, and health check #13

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Merged
jeanpaulsio merged 1 commit into from
Apr 18, 2026
Merged

fix: harden SSR server with keepalive fix, error handling, and health check #13

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1 change: 1 addition & 0 deletions render.yaml
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Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,7 @@ services:
autoDeploy: true
buildCommand: cd web && npm ci && npm run build
startCommand: cd web && node server.js
healthCheckPath: /health
envVars:
- key: NODE_VERSION
value: "22"
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173 changes: 156 additions & 17 deletions web/server.js
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Expand Up @@ -6,33 +6,172 @@ import { fileURLToPath } from "url";
import { dirname, join } from "path";

const __dirname = dirname(fileURLToPath(import.meta.url));
const port = parseInt(process.env.PORT ?? "3000", 10);

const app = express();

// Serve static assets (JS, CSS, images). index: false so all HTML
// routes fall through to the Vike handler below.
// ── Logging ────────────────────────────────────────────────────────────────

// Log slow requests (>5s) and all 5xx errors
app.use((req, res, next) => {
const start = Date.now();
res.on("finish", () => {
const duration = Date.now() - start;
if (duration > 5000 || res.statusCode >= 500) {
console.error(
JSON.stringify({
method: req.method,
path: req.path,
status: res.statusCode,
duration,
timestamp: new Date().toISOString(),
}),
);
}
});
next();
});

// ── Health check ───────────────────────────────────────────────────────────

app.get("/health", (_req, res) => {
res.status(200).json({ status: "ok" });
});

// ── Static assets ──────────────────────────────────────────────────────────

// Serve JS, CSS, images. index: false so all HTML routes fall through to Vike.
app.use(express.static(join(__dirname, "dist/client"), { index: false }));

// All routes handled by Vike SSR
app.get("*", async (req, res) => {
const pageContext = await renderPage({
urlOriginal: req.originalUrl,
headers: req.headers,
// ── Request timeout ────────────────────────────────────────────────────────

// Kill stalled renders after 30s so they don't hang forever
app.use((_req, res, next) => {
res.setTimeout(30_000, () => {
if (!res.headersSent) {
console.error(
JSON.stringify({
error: "request_timeout",
message: "SSR render timed out after 30s",
timestamp: new Date().toISOString(),
}),
);
res.status(504).end("Request timed out");
}
});
next();
});

// ── Vike SSR handler ───────────────────────────────────────────────────────

app.get("*", async (req, res) => {
try {
const pageContext = await renderPage({
urlOriginal: req.originalUrl,
headers: req.headers,
});

const { httpResponse } = pageContext;

if (!httpResponse) {
res.status(404).end();
return;
}

const { httpResponse } = pageContext;
const { statusCode, headers, body } = httpResponse;
headers.forEach(([name, value]) => res.setHeader(name, value));
res.status(statusCode).end(body);
} catch (err) {
console.error(
JSON.stringify({
error: "ssr_render_error",
message: err instanceof Error ? err.message : String(err),
stack: err instanceof Error ? err.stack : undefined,
path: req.originalUrl,
timestamp: new Date().toISOString(),
}),
);

if (!httpResponse) {
res.status(404).end();
return;
if (!res.headersSent) {
res.status(500).end(`<!DOCTYPE html>
<html><head><meta charset="utf-8"><title>Something went wrong</title></head>
<body style="font-family:system-ui;display:flex;justify-content:center;align-items:center;min-height:100vh;margin:0;background:#0f172a;color:#94a3b8">
<div style="text-align:center">
<h1 style="font-size:1.25rem;font-weight:700;color:#e2e8f0">Something went wrong</h1>
<p style="font-size:0.875rem;margin-top:0.5rem">An unexpected error occurred. Try refreshing the page.</p>
<a href="/" style="display:inline-block;margin-top:1rem;padding:0.5rem 1.25rem;background:#6366f1;color:white;border-radius:0.5rem;text-decoration:none;font-size:0.75rem;font-weight:600">Go Home</a>
</div></body></html>`);
}
}
});

// ── Global error handler ───────────────────────────────────────────────────

const { statusCode, headers, body } = httpResponse;
headers.forEach(([name, value]) => res.setHeader(name, value));
res.status(statusCode).end(body);
// Safety net for any unhandled Express errors
app.use((err, _req, res, _next) => {
console.error(
JSON.stringify({
error: "unhandled_express_error",
message: err instanceof Error ? err.message : String(err),
stack: err instanceof Error ? err.stack : undefined,
timestamp: new Date().toISOString(),
}),
);
if (!res.headersSent) {
res.status(500).end("Internal Server Error");
}
});

const port = parseInt(process.env.PORT ?? "3000", 10);
app.listen(port, () => {
console.log(`{{APP_DISPLAY_NAME}} frontend running at http://localhost:${port}`);
// ── Process lifecycle ──────────────────────────────────────────────────────

process.on("uncaughtException", (err) => {
console.error(JSON.stringify({ error: "uncaught_exception", message: err.message, stack: err.stack, timestamp: new Date().toISOString() }));
process.exit(1);
});

process.on("unhandledRejection", (reason) => {
console.error(JSON.stringify({ error: "unhandled_rejection", message: String(reason), timestamp: new Date().toISOString() }));
});

process.on("SIGTERM", () => {
console.log(JSON.stringify({ event: "sigterm", timestamp: new Date().toISOString() }));
process.exit(0);
});

// ── Memory monitoring ──────────────────────────────────────────────────────

setInterval(() => {
const mem = process.memoryUsage();
if (mem.heapUsed > 400 * 1024 * 1024) {
console.warn(
JSON.stringify({
warning: "high_memory",
heapUsed: Math.round(mem.heapUsed / 1024 / 1024) + "MB",
rss: Math.round(mem.rss / 1024 / 1024) + "MB",
timestamp: new Date().toISOString(),
}),
);
}
}, 60_000).unref(); // unref so it doesn't prevent graceful shutdown

// ── Start server ───────────────────────────────────────────────────────────

const server = app.listen(port, () => {
console.log(
JSON.stringify({
event: "server_start",
app: "{{APP_DISPLAY_NAME}}",
port,
node: process.version,
timestamp: new Date().toISOString(),
}),
);
});

// Fix for Cloudflare 502s: Node's default keepAliveTimeout (5s) is too short.
// Cloudflare drops idle connections after ~100-900s. If Node closes first,
// Cloudflare sends a request on a dead socket and returns 502.
// See: https://render.com/docs/troubleshooting-deploys
// See: https://github.com/nodejs/node/issues/59193
server.keepAliveTimeout = 120 * 1000;
server.headersTimeout = 125 * 1000; // Must be > keepAliveTimeout (Node.js requirement)
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