How to end process on specific error in fastify using setErrorHandler? - fastify

Question

In my app I'm connecting to a database and then initialize it. I have two custom plugins for that. First plugin connects to DB, and then it registers the second plugin, which initializes the DB (creates tables, domains etc.)
I want to stop process if an error happens inside those two plugins, since without DB connection and initialization the app won't work.
In app.ts I have
const fastify = Fastify({ logger: true });
fastify.register<ConnectAndInitDBConfig>(ConnectAndInitDB, {
config,
initSqlPath: 'assets/init.sql',
});
Here is the first plugin ConnectAndInitDB
const ConnectAndInitDB: FastifyPluginCallback<ConnectAndInitDBConfig> = (
fastify,
{ config, initSqlPath },
done
) => {
fastify.register(fastifyPostgres, config); // this connects to the DB (fastify-postgres NPM package)
fastify.after(err => {
if (err) {
fastify.log.error(err);
return done(err);
}
console.log('DB Connected.');
});
fastify.register(InitDB, { initSqlPath }); // this initializes the DB
fastify.after(err => {
if (err) {
fastify.log.error(err);
return done(err);
}
console.log('DB Initialized.');
});
fastify.setErrorHandler(function errorHandler(error) {
console.log(`got error`); // this is never called, even if an error happens during initialization of the DB
});
done();
};
Here is the second plugin InitDB
const InitDB: FastifyPluginCallback<{ initSqlPath: string }> = async (
fastify,
{ initSqlPath }: { initSqlPath: string },
done
) => {
try {
const initSql = await (
await promisify(readFile)(join(resolve(), initSqlPath))
).toString();
await fastify.pg.pool.query(initSql);
console.log({ initSql });
} catch (err: Error | unknown) {
return done(err as Error);
}
done();
};
When the error happens inside the InitDB plugin, I see it's logged by fastify logger, but I'm not able to catch it inside the setErrorHandler.
How do I catch any error that happens exactly inside my custom plugins, and let fastify handle all other errors?

Answer 1

You don't need the errorHandler because it is triggered for HTTP errors, not for the fastify server startup errors.
It is quite simple to archive your needs:
// when there is an async func, the `done` arg must be removed
const ConnectAndInitDB = async function (fastify, { config, initSqlPath }) {
await fastify.register(fastifyPostgres, config)
console.log('DB Connected.')
try {
await fastify.register(InitDB, { initSqlPath })
console.log('DB Initialized.')
} catch (error) {
console.log(`got error`)
throw error // bubble up the error so fastify server will not start
}
}