@fastify/postgres

Fastify PostgreSQL connection plugin; with this, you can share the same PostgreSQL connection pool in every part of your server. Under the hood node-postgres is used, the options that you pass to register will be passed to the PostgreSQL pool builder.

Install

npm i pg @fastify/postgres

Usage

Add it to your project with register and you are done! This plugin will add the pg namespace to your Fastify instance, with the following properties:

connect: the function to get a connection from the pool
pool: the pool instance
Client: a client constructor for a single query
query: a utility to perform a query _without_ a transaction
transact: a utility to perform multiple queries _with_ a transaction

Example:

const fastify = require('fastify')()

fastify.register(require('@fastify/postgres'), {
  connectionString: 'postgres://postgres@localhost/postgres'
})

fastify.get('/user/:id', (req, reply) => {
  fastify.pg.connect(onConnect)

  function onConnect (err, client, release) {
    if (err) return reply.send(err)

    client.query(
      'SELECT id, username, hash, salt FROM users WHERE id=$1', [req.params.id],
      function onResult (err, result) {
        release()
        reply.send(err || result)
      }
    )
  }
})

fastify.listen({ port: 3000 }, err => {
  if (err) throw err
  console.log(`server listening on ${fastify.server.address().port}`)
})

Async await is supported as well!

const fastify = require('fastify')()

fastify.register(require('@fastify/postgres'), {
  connectionString: 'postgres://postgres@localhost/postgres'
})

fastify.get('/user/:id', async (req, reply) => {
  const client = await fastify.pg.connect()
  try {
    const { rows } = await client.query(
      'SELECT id, username, hash, salt FROM users WHERE id=$1', [req.params.id],
    )
    // Note: avoid doing expensive computation here, this will block releasing the client
    return rows
  } finally {
    // Release the client immediately after query resolves, or upon error
    client.release()
  }
})

fastify.listen({ port: 3000 }, err => {
  if (err) throw err
  console.log(`server listening on ${fastify.server.address().port}`)
})

Use of pg.query

const fastify = require('fastify')()

fastify.register(require('@fastify/postgres'), {
  connectionString: 'postgres://postgres@localhost/postgres'
})

fastify.get('/user/:id', (req, reply) => {
  fastify.pg.query(
    'SELECT id, username, hash, salt FROM users WHERE id=$1', [req.params.id],
    function onResult (err, result) {
      reply.send(err || result)
    }
  )
})

fastify.listen({ port: 3000 }, err => {
  if (err) throw err
  console.log(`server listening on ${fastify.server.address().port}`)
})

Use of pg.transact

const fastify = require('fastify')()

fastify.register(require('@fastify/postgres'), {
  connectionString: 'postgres://postgres@localhost/postgres'
})

fastify.post('/user/:username', (req, reply) => {
  // will return a promise, fastify will send the result automatically
  return fastify.pg.transact(async client => {
    // will resolve to an id, or reject with an error
    const id = await client.query('INSERT INTO users(username) VALUES($1) RETURNING id', [req.params.username])

    // potentially do something with id

    return id
  })
})

/* or with a transaction callback

fastify.pg.transact(client => {
    return client.query('INSERT INTO users(username) VALUES($1) RETURNING id', [req.params.username])
  },
  function onResult (err, result) {
    reply.send(err || result)
  }
})

*/

/* or with a commit callback

fastify.pg.transact((client, commit) => {
  client.query('INSERT INTO users(username) VALUES($1) RETURNING id', [req.params.username], (err, id) => {
    commit(err, id)
  });
})

*/

fastify.listen({ port: 3000 }, err => {
  if (err) throw err
  console.log(`server listening on ${fastify.server.address().port}`)
})

As you can see there is no need to close the client, since it is done internally. Promises and async await are supported as well.

Name option

If you need to have multiple databases set up, then you can name each one of them by passing name: 'foo'. It will then be accessible as fastify.pg.foo. You can use both unnamed and named postgres connections at once. There can be only one unnamed connection, and it will be accessible as fastify.pg.

const fastify = require('fastify')()

fastify.register(require('@fastify/postgres'), {
  connectionString: 'postgres://postgres@localhost/postgres',
  name: 'foo'
})

fastify.get('/user/:id', (req, reply) => {
  fastify.pg.foo.query(
    'SELECT id, username, hash, salt FROM users WHERE id=$1', [req.params.id],
    function onResult (err, result) {
      reply.send(err || result)
    }
  )
})

fastify.listen({ port: 3000 }, err => {
  if (err) throw err
  console.log(`server listening on ${fastify.server.address().port}`)
})

Native option

If you want maximum performance you can install pg-native, and pass native: true to the plugin options. Note: it requires PostgreSQL client libraries & tools installed, see instructions. Note: trying to use native options without successfully installation of pg-native will return a warning and fallback to regular pg module.

const fastify = require('fastify')()

fastify.register(require('@fastify/postgres'), {
  connectionString: 'postgres://postgres@localhost/postgres',
  native: true
})

fastify.get('/user/:id', (req, reply) => {
  fastify.pg.query(
    'SELECT id, username, hash, salt FROM users WHERE id=$1', [req.params.id],
    function onResult (err, result) {
      reply.send(err || result)
    }
  )
})

fastify.listen({ port: 3000 }, err => {
  if (err) throw err
  console.log(`server listening on ${fastify.server.address().port}`)
})

pg option

If you want to provide your own pg module, for example to support packages like pg-range, you can provide an optional pg option with the patched library to use:

const fastify = require('fastify')()
const pg = require("pg");
require("pg-range").install(pg)

fastify.register(require('@fastify/postgres'), {
  connectionString: 'postgres://postgres@localhost/postgres',
  pg: pg
})

fastify.get('/user/:id', (req, reply) => {
  fastify.pg.query(
    'SELECT id, username, hash, salt FROM users WHERE id=$1', [req.params.id],
    function onResult (err, result) {
      reply.send(err || result)
    }
  )
})

fastify.listen({ port: 3000 }, err => {
  if (err) throw err
  console.log(`server listening on ${fastify.server.address().port}`)
})

Transact route option

It is possible to automatically wrap a route handler in a transaction by using the transact option when registering a route with Fastify. Note that the option must be scoped within a pg options object to take effect.

query commands can then be accessed at request.pg or request.pg[name] and transact can be set for either the root pg client with value true or for a pg client at a particular namespace with value name. Note that the namespace needs to be set when registering the plugin in order to be available on the request object.

// transact set for the route pg client
fastify.get('/user/:id', { pg: { transact: true } }, (req, reply) => {
  // transaction wrapped queries, NO error handling
  req.pg.query('SELECT username FROM users WHERE id=1')
  req.pg.query('SELECT username FROM users WHERE id=2')
  req.pg.query('SELECT username FROM users WHERE id=3')
})

// transact set for a pg client at name
fastify.get('/user/:id', { pg: { transact: 'foo' } }, (req, reply) => {
  // transaction wrapped queries, NO error handling
  req.pg.foo.query('SELECT username FROM users WHERE id=1')
  req.pg.foo.query('SELECT username FROM users WHERE id=2')
  req.pg.foo.query('SELECT username FROM users WHERE id=3')
})

Important: rolling back a transaction relies on the handler failing and being caught by an onError hook. This means that the transaction wrapped route handler must not catch any errors internally.

In the plugin this works by using the preHandler hook to open the transaction, then the onError and onSend hooks to commit or rollback and release the client back to the pool.

TypeScript Usage

Install the compiler and typings for pg module:

npm i -D typescript @types/pg

More examples in the examples/typescript directory.

Development and Testing

Docker approach

First, start postgres with:

$ npm run postgres

Then you can, in another terminal, find the running docker, init the DB, then run the tests:

$ docker ps
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS              PORTS                    NAMES
28341f85c4cd        postgres:9.6-alpine   "docker-entrypoint.s…"   3 minutes ago       Up 3 minutes        0.0.0.0:5432->5432/tcp   jovial_shockley

$ docker exec -ti jovial_shockley /usr/local/bin/psql -d postgres -U postgres  -c 'CREATE TABLE users(id serial PRIMARY KEY, username VARCHAR (50) NOT NULL);'
CREATE TABLE

$ npm test

Custom Postgres approach

1. Set up a database of your choice in a postgres server of your choice
2. Create the required table using

   CREATE TABLE users(id serial PRIMARY KEY, username VARCHAR (50) NOT NULL);

3. Specify a connection string to it in a DATABASE_TEST_URL environment variable when you run the tests

   DATABASE_TEST_URL="postgres://username:password@localhost/something_thats_a_test_database" npm test

Acknowledgements

This project is kindly sponsored by:

• nearForm
• LetzDoIt

License

Licensed under MIT.