Tiny sentinel for a redis cluster in a docker cloud

redis-node-sentinel.js

var redis = require('haredis');
var uuid = require('node-uuid');
var swig = require('swig');

var defaultRedises = '{{REDIS1_PORT_10000_TCP_ADDR}}:10000 {{REDIS2_PORT_10000_TCP_ADDR}}:10000 {{REDIS3_PORT_10000_TCP_ADDR}}:10000';
var template = process.env.REDISES || defaultRedises;
var redises = swig.compile(template)(process.env).split(/\s+/);

var id = process.env.HOSTNAME || uuid.v4();
var keepaliveMilliseconds = process.env.KEEPALIVE_MS || 3000;

console.log("redis-node-sentinel " + id + " monitoring " + redises);

var client = redis.createClient(redises);

var keepAlive = function() {
  var lww = "redis-node-sentinel " + id + " keepalive at " + Date.now();
  // Writing is probably paranoid; testing required
  client.set("haredis:keepalive", lww, function(err, reply) {
    if (err !== null) {
      console.log(lww + " error, aborting");
      throw err;
    } else {
      console.log(lww + " write " + reply);
      setTimeout(keepAlive, keepaliveMilliseconds);
    }
  });
};

keepAlive();