Publishing to an SNS topic in AWS lambda (as a promise)

sns_publisher.js

var _ = require('lodash');
var Q = require('q');
var AWS = require('aws-sdk-q');

function SnsPublisher(topic, options) {
  var topicOptions = {
    params: {
      TopicArn: topic
    }
  };
  var clientOptions = _.defaultsDeep(
    topicOptions,
    options,
    this.clientDefaults
  );
  this.sns = new AWS.SNS(clientOptions);
}

SnsPublisher.prototype = {
  clientDefaults: {
    params: {
      region: 'us-east-1'
    },
    maxRetries: 1
  },
  publish: function(subject, message) {
    if (message.length == 0) return Q(undefined); // no-op promise

    if (!_.isString(message)) {
      message = JSON.stringify(_.toPlainObject(message), null, 2);
    }
    var params = {
      Subject: subject,
      Message: message
    };

    return this.sns.publish(params).q().fail(this.publishFailed);
  },
  publishFailed: function(error) {
    if (error.stack) { return console.log(error.stack); }
    if (error.message) { return console.log(error.message); }

    return console.log(error);
  }
};

module.exports = SnsPublisher;