redbird/lib/redis-backend.js
2018-06-29 15:47:19 +02:00

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"use strict";
var redis = require('redis');
var Promise = require('bluebird');
var _ = require('lodash');
Promise.promisifyAll(redis);
/**
Instantiates a Redis Redbird backend.
opts: {
prefix: '',
port: 6739,
host: 'localhost',
opts: {}
}
*/
function RedisBackend(port, hostname, opts)
{
if(!(this instanceof RedisBackend)){
return new RedisBackend(port, hostname, opts);
}
opts = opts || {};
port = port || 6379;
hostname = hostname || 'localhost';
this.redis = redis.createClient(port, hostname, opts);
this.publish = redis.createClient(port, hostname, opts);
this.prefix = opts.prefix + '';
this.baseKey = baseKey(this.prefix);
}
/**
Returns a Promise that resolves to an array with all the
registered services and removes the expired ones.
*/
RedisBackend.prototype.getServices = function(){
var _this = this;
var redis = this.redis;
var baseKey = this.baseKey;
//
// Get all members in the service set.
//
return redis.smembersAsync(baseKey + 'ids').then(function(serviceIds){
return Promise.all(_.map(serviceIds, function(id){
return _this.getService(id);
}));
}).then(function(services){
// Clean expired services
return _.compact(services);
});
}
RedisBackend.prototype.getService = function(id){
var redis = this.redis;
//
// Get service hash
//
return redis.hgetallAsync(this.baseKey + id).then(function(service){
if(service){
return service;
}else{
//
// Service has expired, we must delete it from the service set.
//
return redis.sremAsync(id);
}
});
}
RedisBackend.prototype.register = function(service){
var redis = this.redis;
var publish = this.publish;
var baseKey = this.baseKey;
//
// Get unique service ID.
//
return redis.incrAsync(baseKey + 'counter').then(function(id){
// Store it
redis.hset(baseKey + id, service).then(function(){
return id;
})
}).then(function(id){
//
// // Publish a meesage so that the proxy can react faster to a new registration.
//
return publish.publishAsync(baseKey + 'registered', id).then(function(){
return id;
})
});
}
RedisBackend.prototype.ping = function(id){
return this.redis.pexpireAsync(id, 5000);
}
function baseKey(prefix){
return 'redbird-' + prefix + '-services-';
}
module.exports = RedisBackend;