Fastify Setup

LoadFlux integrates as a Fastify plugin.

Basic setup

import Fastify from "fastify";
import { loadfluxFastify } from "loadflux";

const app = Fastify();

app.register(loadfluxFastify({
  auth: {
    username: "admin",
    password: "secret",
  },
}));

// Your routes
app.get("/api/users", async () => {
  return [{ id: 1, name: "Alice" }];
});

app.listen({ port: 3000 }, () => {
  console.log("Server running on http://localhost:3000");
  console.log("Dashboard at http://localhost:3000/loadflux");
});

Custom path

app.register(loadfluxFastify({
  path: "/monitor",
  auth: { username: "admin", password: "secret" },
}));

Full example

import Fastify from "fastify";
import { loadfluxFastify } from "loadflux";

const app = Fastify({ logger: true });

app.register(loadfluxFastify({
  path: "/loadflux",
  auth: {
    username: process.env.LOADFLUX_USERNAME || "admin",
    password: process.env.LOADFLUX_PASSWORD || "password",
  },
  retention: { days: 30 },
  slowRequestThreshold: 1000,
  excludeRoutes: ["/health"],
}));

app.get("/health", async () => "ok");
app.get("/api/users", async () => [{ id: 1, name: "Alice" }]);

app.listen({ port: 3000 });

How it works

The Fastify plugin:

1. Registers dashboard routes inside an encapsulated Fastify context with body parsing disabled (so the raw API handler can read POST bodies directly).
2. Adds an onResponse hook to record metrics for all non-LoadFlux routes. Fastify provides reply.elapsedTime for precise request duration.

Route patterns are resolved via request.routeOptions.url, so parameterized routes like /api/users/:id are grouped correctly.