pg-pool-adapter

pg-pool-adapter is an adapter for integrating Knex with libraries or frameworks that expect a pg.Pool interface. For instance, you can integrate LangGraph's PostgresSaver with an existing codebase that uses Knex.

Using this adapter, you can avoid having two separate pools in the same application, allowing it to manage connections more efficiently.

Summary

• Allows Knex's tarn-based pool to behave like a pg.Pool instance.
• Adheres strictly to promises, avoiding callback-style APIs.
• Provides errors for unsupported operations.

Installation

Install the required packages:

npm install knex pg pg-pool-adapter

Add pg-pool-adapter to your project and use it like this:

import { PgPoolAdapter } from 'pg-pool-adapter'
import knex from 'knex'

const knexInstance = knex({
  client: 'pg',
  connection: process.env.DATABASE_URL,
  pool: { min: 2, max: 10 },
})

// Create an adapter instance
const pgPool = PgPoolAdapter.fromKnex(knexInstance)

// Use pgPool as you would normally use pg.Pool
pgPool.query('SELECT * FROM users').then((result) => console.log(result.rows))

Supported Features

• Execute queries via pool.query()
• Acquire clients via pool.connect()
• Release acquired clients via client.release()

Unsupported Features

1. The query method does not support callback-style arguments. Use promises instead.
2. Releasing a client with the destroy flag will throw an error.
3. The adapter does not support ending the pool directly. You must end the original Knex pool if necessary.
4. Event listeners are currently not supported.