@openstatus/health-cloudflare-d1

Cloudflare D1 probe for @openstatus/health. Runs select 1 through the D1Database binding of a Worker and fails the check when the statement does.

deno add jsr:@openstatus/health jsr:@openstatus/health-cloudflare-d1
npm install @openstatus/health @openstatus/health-cloudflare-d1

import { createLazyHealthHandler } from "@openstatus/health";
import { d1Probe } from "@openstatus/health-cloudflare-d1";

interface Env {
  DB: D1Database;
}

export default {
  fetch: createLazyHealthHandler<Request, Env>((env) => ({
    path: "/health",
    probes: [d1Probe({ db: env.DB })],
  })),
};

Bindings only exist inside fetch(request, env) in Workers, but the handler must be built once or every request gets a fresh cache and the probe runs on every poll. createLazyHealthHandler runs your callback on the first request and reuses the handler it builds; with Hono, build the probe once inside a route handler that receives c.env and memoise it the same way. The probe calls db.prepare("select 1").first(), which round-trips to the D1 storage and needs no table. For the colo and version the response came from, add @openstatus/health-cloudflare's extend hook.

d1Probe({
  db: env.DB,
  // optional overrides from the Probe contract
  name: "d1",
  critical: false,
  timeoutMs: 1000,
  skip: () => env.HEALTH_SKIP_D1 === "true",
});

The factory validates db when it is called, before skip is ever consulted, so skip cannot stand in for a missing binding; leave the probe out of probes instead when the Worker may run without D1.

Critical by default: a D1 that does not answer usually means requests cannot be served, so the report turns unhealthy. Set critical: false when the Worker can serve without it.

The binding is typed structurally as { prepare(query): { first() } }, so the package has no dependency on @cloudflare/workers-types and works with the types wrangler types generates. The factory throws ProbeConfigError at construction when the binding has no prepare().

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