f0ssel-serverless

@neondatabase/serverless [BETA]

This package from Neon shims the node-postgres pg library to work on serverless runtimes such as Cloudflare Workers and Vercel Edge Functions — places where TCP sockets are not available — via a WebSocket proxy.

The package also works in web browsers, but in most cases it's not appropriate to publicly deploy that way because it would reveal your Postgres credentials.

How to use it

Where you'd otherwise install pg and @types/pg, instead run npm install @neondatabase/serverless.

Then use it the same way you'd use pg. For example, with your Neon database connection string available as DATABASE_URL:

import { Pool } from '@neondatabase/serverless';

export default {
  async fetch(req, env, ctx) {
    const pool = new Pool({ connectionString: env.DATABASE_URL });
    const { rows: [{ now }] } = await pool.query('SELECT now()');
    ctx.waitUntil(pool.end());
    return new Response(now);
  }
}

For a complete usage example on Cloudflare Workers, see https://github.com/neondatabase/serverless-cfworker-demo.

Notes

• Pooling: in general, serverless platforms don't keep WebSocket connections alive between requests. So it won't generally work to connect a database client (or establish a connection pool) outside of the function that's run on each request. You can of course use a Pool within your request handler as a slightly terser way to acquire and connect a Client.

• Cloudflare: brief queries such as the one shown above can generally be run on Cloudflare’s free plan. Queries with larger result sets may exceed the 10ms CPU time available to Workers on the free plan: in that case you’ll see a Cloudflare error page and will need to upgrade your Cloudflare service.

Run on Node

If you're running on Node, or anywhere else where a TCP connection can be made via net.Socket, you could just use node-postgres.

Alternatively, you can use this library by providing a WebSocket constructor, like so:

import ws from 'ws';
import { neonConfig, Pool } from '@neondatabase/serverless';
neonConfig.webSocketConstructor = ws; 

const pool = new Pool({ connectionString: 'postgres://...' });

Run your own WebSocket proxy

The package comes configured to connect to a Neon database over a secure (wss:) WebSocket.

But you can also run your own WebSocket proxy, and configure it to allow onward connections to your own Postgres instances.

First, you'll need to set up the proxy itself somewhere public-facing (or on localhost for development). See https://github.com/neondatabase/wsproxy for the Go code and instructions.

There are two ways you can secure this.

1. Set up nginx as a TLS proxy in front of wsproxy. Example shell commands to achieve this can be found in DEPLOY.sh. Onward traffic to Postgres is not secured by this method, so Postgres should be running on the same machine or be reached over a private network.

2. Use experimental pure-JS Postgres connection encryption via subtls. Please note that subtls is experimental software and this configuration is not suitable for use in production. There's no need for nginx in this scenario, and the Postgres connection is encrypted end-to-end. You get this form of encryption if you set neonConfig.useSecureWebSocket to false and append ?sslmode=verify-full (or similar) to your connection string. TLS version 1.3 must be supported by the Postgres back-end.

Second, you'll need to set some configuration options on this package, including at a minimum the wsProxy option (details below).

Configuration

There are two ways to set configuration options:

1. You can import neonConfig from the package and set global default options on it.
2. You can set options on individual Client instances using their neonConfig property.

For example:

import { Client, neonConfig } from '@neondatabase/serverless';

// set default options for all clients
neonConfig.wsProxy = (host, port) => `my-wsproxy.example.com/v1?address=${host}:${port}`;
neonConfig.rootCerts = `
-----BEGIN CERTIFICATE-----
MIIFazCCA1OgAwIBAgIRAIIQz7DSQONZRGPgu2OCiwAwDQYJKoZIhvcNAQELBQAw ...
-----END CERTIFICATE-----
`;

// override default options on an individual client
const client = new Client(env.DATABASE_URL);
client.neonConfig.wsProxy = (host, port) => `my-other-wsproxy.example.com/v1?address=${host}:${port}`;

webSocketContructor: typeof WebSocket | undefined

Set this parameter if you're using the driver in an environment where globalThis.WebSocket is not defined, such as Node.js.

For example:

import ws from 'ws';
import { neonConfig } from '@neondatabase/serverless';
neonConfig.webSocketConstructor = ws; 

wsProxy: string | (host: string, port: number | string) => string

The wsProxy option should point to the WebSocket proxy you just set up. It can either be a string, which will have ?address=host:port appended to it, or a function with the signature (host: string, port: number | string) => string. Either way, the protocol must not be included, because this depends on other options. For example, when using the wsproxy proxy, the wsProxy option should look something like this:

// either:
neonConfig.wsProxy = (host, port) => `my-wsproxy.example.com/v1?address=${host}:${port}`
// or (with identical effect):
neonConfig.wsProxy = 'my-wsproxy.example.com/v1';

useSecureWebSocket: boolean

This option switches between secure (the default) and insecure WebSockets.

To use experimental pure-JS encryption, set this to false and append ?sslmode=verify-full to your database connection string. Remember that pure-JS encryption is currently experimental and not suitable for use in production.

pipelineConnect: "password" | false

To speed up connection times, the driver will pipeline the first three messages to the database (startup, authentication and first query) if pipelineConnect is set to "password". Note that this will only work if you've configured cleartext password authentication for the relevant user and database.

The default is "password". If your connection doesn't support password authentication, set it to false instead.

coalesceWrites: boolean

When this option is true, multiple network writes generated in a single iteration of the JavaScript run-loop are coalesced into a single WebSocket message. Since node-postgres sends a lot of very short messages, this may reduce TCP/IP overhead. It defaults to true.

rootCerts: string /* PEM format */

Only when using the experimental pure-JS TLS implementation, this option determines what root (certificate authority) certificates are trusted. The default value of rootCerts is the ISRG Root X1 certificate, which is appropriate for servers secured with Let’s Encrypt.

If you're using any other certificate authority to secure Postgres connections, provide the root certificate(s) in PEM format to the rootCerts option.

pipelineTLS: boolean

Only when using experimental pure-JS encryption, the driver will pipeline the SSL request message and TLS Client Hello if pipelineTLS is set to true. Currently, this is only supported by Neon database hosts, and will fail when communicating with an ordinary Postgres or pgbouncer back-end.

The default is true. For non-Neon hosts, set it to false instead.

Development

The code is at https://github.com/neondatabase/serverless. Most of the interesting parts are in shims/net/index.ts and export/index.ts.

• To update the npm package, run npm run export, then cd dist/npm and npm publish.

• To run or deploy the simple test app on Cloudflare, create a .dev.vars file containing DATABASE_URL=postgres://connection_string, run npx wrangler dev --local or npx wrangler publish.

• To run the latencies test app in a browser, create a .dev.vars file as above, run npm run browser and visit http://localhost:7070/dist/browser/. To include debug output and avoid minification, use npm run browserDebug instead.

• To run the latencies test app in node, create a .dev.vars file as above and run npm run node. To include debug output and avoid minification, use npm run nodeDebug instead.