postgres-watcher

Watches your PostgreSQL DB for changes. Before using this module you need to set up some triggers, for example with postgres-triggers.

Heavily inspired by this blog post by @fritzy.

This module is in its early stages. Feedback and PRs welcome!

Install

npm i postgres-watcher

Usage (API)

This module is basically an event emitter. It doesn't make any assumption about your trigger payload, except that it should be a JSON object.

const Watcher = require('postgres-watcher')
const watcher = Watcher({
  db: 'postgres://foo@localhost:5432/db',
  channel: 'table_update', // optional
  
  // optional filter function.
  // only payloads which return a truthy value 
  // will later emit a 'change' event
  filter: function (payload) { return payload.id >= 42 }
})
 
// listen for changes
watcher.on('change', function (change) {
  console.log(change) // { id: 1, type: 'INSERT', table: 'foo', ... }
})
 
watcher.on('error', console.error.bind(console))
 
// start watching, callback is optional
watcher.start(function(err) {
  if (err) throw err
  console.log(watcher.running) // true
})
 
// insert, update, delete rows in your db...
 
// stop watching, callback is optional
watcher.stop(function () {})

TODO

there is certainly stuff to do ;-)

Tests

You need to give it a database connection string to be able to run the tests.

POSTGRES=postgres://postgres@localhost:5432/postgres npm test

License

MIT