Nexus/apps/web/src/app/api/ready/route.ts

import { NextResponse } from "next/server";
import { prisma } from "@nexus/db";
import { createConnection } from "net";

export const dynamic = "force-dynamic";
export const runtime = "nodejs";

const REDIS_URL = process.env["REDIS_URL"] ?? "redis://localhost:6380";

async function checkPostgres(): Promise<"ok" | "error"> {
  try {
    await prisma.$queryRaw`SELECT 1`;
    return "ok";
  } catch {
    return "error";
  }
}

/**
 * Lightweight Redis PING check using a raw TCP socket.
 * Avoids importing ioredis (which is only a dependency of @nexus/api).
 */
async function checkRedis(): Promise<"ok" | "error"> {
  return new Promise((resolve) => {
    try {
      const url = new URL(REDIS_URL);
      const host = url.hostname || "localhost";
      const port = parseInt(url.port || "6379", 10);
      const timeout = 3000;

      const socket = createConnection({ host, port }, () => {
        // Send Redis PING command using RESP protocol
        socket.write("*1\r\n$4\r\nPING\r\n");
      });

      socket.setTimeout(timeout);

      socket.on("data", (data) => {
        const response = data.toString();
        socket.destroy();
        // Redis responds with +PONG\r\n
        resolve(response.includes("PONG") ? "ok" : "error");
      });

      socket.on("timeout", () => {
        socket.destroy();
        resolve("error");
      });

      socket.on("error", () => {
        socket.destroy();
        resolve("error");
      });
    } catch {
      resolve("error");
    }
  });
}

export async function GET() {
  const [postgres, redis] = await Promise.all([checkPostgres(), checkRedis()]);

  const allHealthy = postgres === "ok" && redis === "ok";

  return NextResponse.json(
    {
      status: allHealthy ? "ready" : "not_ready",
      postgres,
      redis,
    },
    { status: allHealthy ? 200 : 503 },
  );
}