node-serf

node-serf

Serf management and orchestration client.

Aim

To provide a interface for communication with Serf daemon via the RPC Protocol.

Installation

npm install --save node-serf

Quick Start

Just send the body. The header and Seq values have been taken care of for you. Commands without response bodies will invoke the callback upon acknowledgement by the Serf agent. Commands with response bodies will invoke the callback with the response.

var Serf = require('node-serf');

// Connection to Serf agent at the default, "127.0.0.1:7373"
var client = Serf.connect(function (err) {
  assert.ifError(err);
  console.log('connected');

  client.join({Existing: ['127.0.0.1:7946'], Replay: false}, function (err, response) {
    assert.ifError(err);

    setTimeout(function() {
      client.leave();
    }, 1000);

  });
});

API Documentation

Please refer to the Serf RPC documentation for authoritative information on each command.

Serf.connect([options][, callback])

• options <Object> Connection options. If omitted, defaults to localhost:7373.
• callback <Function> Invoked after connected and handshake completed.

Returns a new Serf client.

The options argument typically contains port (required) and host (defaults to 'localhost'), but any of the socket.connect options are allowed.

serf.handshake([callback]) (ref)

This is called automatically upon connecting. You should not call this directly.

serf.auth(body[, callback]) (ref)

serf.end()

Disconnects from the Serf agent. You must call this to close the socket so that node.js may gracefully exit. Alternatively, call serf.leave() to close both the socket and the Serf agent; once called, you must restart the agent to rejoin, however.

serf.leave([callback]) (ref)

serf.forceLeave(body[, callback]) (ref)

serf.event(body[, callback]) (ref)

serf.join(body[, callback]) (ref)

serf.members(callback) (ref)

serf.membersFiltered(filter, callback) (ref)

serf.tags(body[, callback]) (ref)

serf.stream(body[, callback]) (ref)

Returns an event emitter that can be handled with 'listen', 'data', 'error' and 'stop' listeners. This is not a node.js Stream, so it cannot be piped, paused, etc. Messages are not buffered, so messages will be dropped if listeners are not attached.

If a callback is provided, it will be added to the 'listen' listeners.

The returned emitter has a stop method that ends the stream. If a callback is provided, it will be added to the 'stop' listeners.

var stream = client.stream({Type: '*'}, function (err) {
  // Called after the stream is connected
  assert.ifError(err);
});

stream.on('listen', function (err) {
  // Also called after the stream is connected
});

stream.on('error', console.error.bind(console)); // log errors

stream.on('data', function (result) {
  // Handle streaming message
  console.log(result);

  // Stop streaming
  stream.stop(function (err) {
    // Called when the stream is stopped
  });
});

stream.on('stop', function () {
  // Also emitted when the stream is stopped
});

serf.monitor(body[, callback]) (ref)

Listen using the same syntax as serf.stream.

serf.query(body, callback) (ref)

Issues a new query. Listen using the same syntax as serf.stream. There are three Types of responses: 'ack', 'response' and 'done'. The 'data' event is invoked when any type of response is received. When the 'done' response is received, the 'stop' event will also be emitted.

Note that there appears to be a bug in Serf wherein responses are sometimes sent with the form {From: '', Payload: null, Type: 'response'}. You should check that Payload is not null before attempting to access it.

serf.respond(body[, callback]) (ref)

• body <Object> Of the form {ID: number, Payload: string|bytes[, ...]}

Use with serf.stream. Your response ID property must match the query ID.

serf.installKey(body[, callback]) (ref)

serf.useKey(body[, callback]) (ref)

serf.removeKey(body[, callback]) (ref)

serf.listKeys(callback) (ref)

serf.stats(callback) (ref)

serf.getCoordinate(callback) (ref)

Event: 'error'

The Serf client extends node.js's socket class. In addition to handling errors passed to the command callbacks and errors raised on streams created by the monitor, stream and query commands, you should subscribe to the client's 'error' event, which will be invoked in case of a socket error unrelated to a Serf command (such as a network fault). If you do not, these errors will bubble up and become uncaught exceptions.

var client = Serf.connect({port: 7373}, function (err) {
  assert.ifError(err);
  /// do stuff
});

client.on('error', function (err) {
  // handle error
})

Notes

• Serf RPC Protocol docs: https://github.com/hashicorp/serf/blob/master/website/source/docs/agent/rpc.html.markdown