@prairielearn/named-locks

Uses Postgres row-level locks to grant exclusive access to resources.

Usage

You must first call init with Postgres connection details and an idle error handler:

``ts
import { init } from '@prairielearn/named-locks';

await init(
{
user: 'postgres',
// ... other Postgres config
},
(err) => {
throw err;
},
);
`

You can then obtain a lock and do work while it is held. The lock will be automatically released once the provided function either resolves or rejects.

`ts
import { doWithLock } from '@prairielearn/named-locks';

await doWithLock('name', {}, async () => {
console.log('Doing some work');
});
`

Optionally, you may configure the lock to automatically "renew" itself by periodically making no-op queries in the background. This is useful for operations that may take longer than the configured Postgres idle session timeout.

`ts
import { doWithLock } from '@prairielearn/named-locks';

await doWithLock(
'name',
{
autoRenew: true,
},
async () => {
console.log('Doing some work');
},
);
``