@npmcorp/etcdjs NPM

@npmcorp/etcdjs

npm fork of etcdjs

Low level etcd v2 & v3 client written in Javascript with failover support

npm install @npmcorp/etcdjs

Usage

Pass a connection string

var etcdjs = require('@npmcorp/etcdjs')
var store = etcdjs('127.0.0.1:4001')

store.set('hello', 'world', function(err, result) {
  store.get('hello', function(err, result) {
    console.log('hello:', result.node.value)
  })
})

If you have more than run instance of etcd running you can pass an array to load balance

var store = etcdjs(['127.0.0.1:4001', '127.0.0.1:4002', '127.0.0.1:4003'])

If you have a discovery token from https://discovery.etcd.io/ you can also pass that

var store = etcdjs('https://discovery.etcd.io/my-token')

etcdjs will automatically refresh its internal host list every 30s so you can transparently add more machines to your cluster without updating your seed host list.

API

`store = etcd(host, opts)`

host should be a etcd host (or an array of hosts) and opts default to

{
  refresh: false,        // refresh the interval host list automatically
  timeout: 60 * 1000,    // default timeout for ops
  json: false            // stringify/parse all values as JSON
}

Note: The refresh option will try to discover additional etcd hosts via the etcd /machines endpoint which may not always return hostnames which are routable. Make sure the endpoint returns what you expect before turning on this feature.

`store.get(key, [opts], cb)`

Get a key. opts defaults to

{
  recursive: false,
  sorted: false,
  json: false,      // parse value as JSON for this request
  wait: false,
  waitIndex: (none)
}

`store.set(key, value, [opts], [cb])`

Set a key. opts defaults to

{
  ttl: (none),
  dir: false,
  json: false,      // stringify value as JSON for this request
  prevExist: (none),
  prevValue: (none),
  prevIndex: (none)
}

`store.update(key, value, [opts], [cb])`

Set a key if it already exists. Same as set(key, value, {prevExists: true})

`store.del(key, [opts], [cb])`

Delete a key. opts defaults to

{
  recursive: false,
  dir: false,
  prevExist: (none),
  prevValue: (none),
  prevIndex: (none)
}

`store.mkdir(key, [opts], [cb])`

Create a directory. Same as set(key, null, {dir: true})

`store.rmdir(key, [opts], [cb])`

Remove a directory. Same as del(key, {dir: true})

`store.wait(key, [opts], [cb])`

Wait a key to change. Same as get(key, {wait: true}) except the callback is called with a third argument next that will wait for the next change.

store.wait('hello', function onchange (err, result, next) {
  console.log('change!', result);
  next(onchange); // next will set waitIndex so we do not miss events
});

.wait returns a destroy function which can be used to kill a waiting request.

var destroy = store.wait('hello', function onchange (err, result, next) {
  // ... do stuff ..
})

destroy()
store.set('key', 'value') // won't trigger the wait