Node.js Backend

Setup

import { createGunsoleClient } from "gunsole-js";

const gun = createGunsoleClient({
  projectId: "my-api",
  apiKey: "dev",
  mode: "local",
  env: process.env.NODE_ENV,
  appName: "api-server",
  appVersion: process.env.npm_package_version,
  defaultTags: {
    service: "api",
  },
});

// Catch unhandled errors
gun.attachGlobalErrorHandlers();

Express middleware

Log every request:

import express from "express";

const app = express();

app.use((req, res, next) => {
  const start = Date.now();

  res.on("finish", () => {
    const duration = Date.now() - start;
    const level = res.statusCode >= 500 ? "error" : res.statusCode >= 400 ? "warn" : "info";

    gun[level]({
      bucket: "http",
      message: `${req.method} ${req.path} → ${res.statusCode} (${duration}ms)`,
      context: {
        method: req.method,
        path: req.path,
        statusCode: res.statusCode,
        duration,
        userAgent: req.get("user-agent"),
        ip: req.ip,
      },
      tags: {
        method: req.method,
        route: req.route?.path || req.path,
        status: String(res.statusCode),
      },
    });
  });

  next();
});

Database queries

async function query(sql, params) {
  const start = Date.now();
  try {
    const result = await db.query(sql, params);
    gun.debug({
      bucket: "db",
      message: `Query OK (${Date.now() - start}ms)`,
      context: { sql, params, rowCount: result.rowCount },
      tags: { operation: sql.trim().split(" ")[0].toUpperCase() },
    });
    return result;
  } catch (err) {
    gun.error({
      bucket: "db",
      message: `Query failed: ${err.message}`,
      context: { sql, params, error: err.message },
      tags: { operation: sql.trim().split(" ")[0].toUpperCase() },
    });
    throw err;
  }
}

Graceful shutdown

Flush remaining logs before exiting:

process.on("SIGTERM", async () => {
  await gun.flush();
  gun.destroy();
  process.exit(0);
});

Custom fetch (Node.js < 18)

If you’re on Node.js < 18 where fetch isn’t built-in:

import fetch from "node-fetch";

const gun = createGunsoleClient({
  projectId: "my-api",
  apiKey: "dev",
  mode: "local",
  fetch: fetch,
});