@openstatus/health-mysql

MySQL / MariaDB probe for @openstatus/health. Runs select 1 through a mysql2/promise pool or connection and fails the check when the round trip does.

deno add jsr:@openstatus/health jsr:@openstatus/health-mysql
npm install @openstatus/health @openstatus/health-mysql

import { createPool } from "mysql2/promise";
import { createHealthHandler } from "@openstatus/health";
import { mysqlProbe } from "@openstatus/health-mysql";

const pool = createPool(env.DATABASE_URL);

Deno.serve(
  createHealthHandler({ probes: [mysqlProbe({ client: pool })] }),
);

Pass the promise API (mysql2/promise), not the callback one: the callback query() returns a query object instead of a promise, which the probe reports as a failed check rather than silently passing. Prefer a pool over a single connection so the health endpoint never holds a connection open or collides with request traffic.

mysqlProbe({
  client: pool,
  // optional overrides from the Probe contract
  name: "primary",
  critical: false,
  timeoutMs: 2000,
  skip: () => env.DATABASE_URL == null,
});

Critical by default: a MySQL that does not answer usually means requests cannot be served, so the report turns unhealthy and the instance is taken out of rotation. Set critical: false for a replica or reporting database.

The client is typed structurally as { query(sql): PromiseLike<...> }, so mysql2 is an optional peer dependency for its types only and the probe adds no runtime import of it. The factory throws ProbeConfigError at construction when the client has no query().

About openstatus

openstatus is the open-source uptime monitoring and status page platform. This package is part of @openstatus/health, the /health endpoints behind openstatus's own services, extracted so any JavaScript server can expose one. Point an openstatus monitor at the endpoint and assert on status in the body to be alerted on degraded before it becomes unhealthy.

Source: github.com/openstatusHQ/health. Issues and PRs welcome.

License

MIT