What I’ve learned this week: Dropbox, Spark and more

1. Dropbox Dropbox is shutting down its two apps: Mailbox and Carousel. I’ve been using both apps heavily recently. The most important feature of Mailbox is auto-swipe. Other competitors also have similar features, but they require much more effort to setup, while Mailbox only requires tap and hold. Easy like a piece of cake. Auto-swipe saves me from going through 14k+ emails so far. Carousel saved me lots of iPhone space by uploading my photos to Dropbox. I heard that they will integrate important features of Carousel into Dropbox, so I will not miss Carousel too much, compare to Mailbox. Without Mailbox around, I will have to manually setup my filters in a bunch of mailboxes. 2. Spark The different between Spark submission tool and Hadoop is that, by default Hadoop uses all available machines (cores) for a single job, provide that input is big enough to be distributed into all machines. Spark, on the other hand, only use 2 cores for executors and 1 core for driver. In order to run Spark with all available cores, you first need to figure out how many executors there are on your cluster. I wonder what leads to the decision in Spark submission tool design. 3. Miscellaneous It is very hard for me to think about what I’ve leaned by the end of a week. I’d better write and update a draft right after I learned something, when the memory still fresh. Oh yes, I still need to write two meeting summaries for this week, so I’d better get going. Hence the short blog post.

Mailbox (from Dropbox) is using Nodemailer to send your emails from Amazon AWS

So I started testing Mailbox on my iPhone and my Mac recently. It has a very elegant interface and a nice Snooze feature (basically you can tell Mailbox to put some messages back to your inbox to process at a later time – this is quite similar to a Chrome extension — Boomerang). The Mac version is beta, but the iPhone version has been around for more than a year, so I don’t think the core functions will change any time soon. One thing I notice about Mailbox is they don’t send email using Gmail SMTP servers. Wait. Something definitely wrong here. The question is Why? The Mailbox app has granted full access to Gmail account, so why don’t they just use Gmail’s SMTP to send mail? Instead, they use Nodemailer on Amazon AWS. What the hell? Return-Path: <> Received: from hedwig-51.prd.orcali.com (ec2-54-85-253-165.compute-1.amazonaws.com. []) by mx.google.com with ESMTPSA id u2sm2020155qap.22.2014. for <> (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 28 Oct 2014 11:54:28 -0700 (PDT) Date: Tue, 28 Oct 2014 11:54:28 -0700 (PDT) X-Google-Original-Date: Tue, 28 Oct 2014 18:54:27 GMT MIME-Version: 1.0 X-Mailer: Nodemailer (0.5.0; +http://www.nodemailer.com/) So what is the point of promoting domain keys, or DKIM? Why not send email using a legitimate and foolproof? Instead, they send users email from a fake SMTP server hosted somewhere on Amazon AWS. I don’t get their point. Update: Thanks Sean Beausoleil and Andris Reinman for clearing that up. I would definitely prefer Amazon AWS over my own IP address to be revealed in email headers.