Category: Technology

Android Teleportation (or silly location restrictions)

Post author By Yoav Aner
Post date 8 February, 2014

My wife and I recently had a baby. Amongst the toys and cloths we received as gifts, there were a few CDs and DVDs with music for the little one. We then realised that we no longer have a CD or DVD drive in our computers. So we bought an external USB DVD/CD. When playing the DVDs, the region-selection menu appeared. I nearly forgot about it. Oh, the good ol’ copy-protection of the 90’s. So I chalked it up as one of those oddities of life, and thought how silly it seems today in the Internet age and all that. My wife is japanese, and I’m Israeli. And we live in Berlin. Naturally each side of the family wanted to send us Music in their own language, so there you go.

Only a few days later, my wife asked for my help with her Nexus 7. She bought a few eBooks from a Japanese site. Those work fine on her iPhone and Mac. But somehow the Play store won’t install the app (never mind the question why someone needs a bespoke app to read books).

“This item is not available in your country”.

This time I was determined to work around this.

Here’s a quick howto which does not require a rooted android.

Route53 healthcheck failover for SSL pages with nginx

Post author By Yoav Aner
Post date 6 January, 2014

UPDATE: AWS recently introduced SSL Health checks. So the method in this post should no longer be necessary.

Amazon Route53 offers a DNS healthcheck that allows you to failover to another host / region if one IP is not responsive. This works great if you want to create a secondary site, or even a simple maintenance page to give your users a little more info than just an empty browser window.

There are some limitations to the healthchecks currently. Route53 allows you to choose between TCP and HTTP. However, there’s no HTTPS / SSL support for URLs.

So what can you do if your site is running only with SSL?

monitoring Security Technology

Getting a bit creepy

Post author By Yoav Aner
Post date 25 August, 2013

I spend a lot of time working with monitoring solutions, and like to measure and track things. The information we collect from our apps tells us a lot about what’s going on. Who’s using it. How frequently they access it. Where they are from. How much time they spend accessing the app etc. And then there’s a lot we can do as app owners with this data. We can measure it, trend it, slice and dice and produce nice reports. We can also action on this info. Offer people stuff based on their behaviour. Use those ‘lifecycle’ emails to improve conversion. Increase our sales. Bring people back to using our products.

I’m getting used to those supposedly-personal email from Matt, the founder of Widgets inc. who’s “just checking if I need any help using the product”, or Stuart from Rackspace who has “only one question”. I know it’s automated, but it’s fine. As long as I can hit reply and actually reach a person, that’s ok with me. I pretend to not notice.

However, I’m feeling recently that some of those emails get a little creepy. A couple of random examples:

graphite monitoring ruby Technology

Measure everything

Post author By Yoav Aner
Post date 2 August, 2013

Just a quick link to my recent talk at Ruby User Group Berlin

Slides are available on github

optimization Performance rails ruby Technology

Matryoshka Fragment Caching in Rails

Post author By Yoav Aner
Post date 16 July, 2013

“Russian doll Caching” gained some popularity recently, I suspect in part due to its catchy (or cachie?) name and how easy it is to visualize the concept. Rails 4 should have this improved caching available by default. With Rails 3 you need to install the cache-digests gem. It’s pretty easy to get started with it, and the documentation is clear. It makes a lot of sense to start using it in your Rails app. I won’t attempt to cover the basics and will assume you are already familiar with it. I want to talk about a specific aspect of fragment caching surrounding the generation of the cache keys.

graphite monitoring Technology

Graphite Alerts with Monit

Post author By Yoav Aner
Post date 7 January, 2013

I love Graphite. It’s the most robust, flexible, kick-ass monitoring tool out there. But when I say monitoring, I’m actually not describing what graphite really does. In fact, it does almost anything but monitoring. It collects metrics via carbon, it stores them using whisper, and it provides a front-end (both API and web-based), via graphite-web. It does not however monitor anything, and certainly does not alert when certain things happen (or fail to happen).

So graphite is great for collecting, viewing and analyzing data, particularly with the multitude of dashboard front-ends, my favourite being giraffe ;-). But what can you do when you want to get an email or a text message when, say, carbon throws some errors, or your web server starts to bleed with 500’s like there’s no tomorrow? Even better – do you want to get an email when your conversion signup rates drops below a certain mark??

Monitoring graphite

So what can you use if you want to monitor stuff using graphite? And what kind of stuff can you monitor? I’ve come across a really great approach using nagios. In fact, I ‘borrowed’ the method the author was using for alerting on 500 errors for my own approach. So I wanted to do something very similar, but I really didn’t want nagios. It’s an overkill for me, if all I want is to get an email (or run a script) when something goes wrong.

Security Technology

I’m not pinterested in spam

Post author By Yoav Aner
Post date 10 November, 2012

Just a quick rant this time.

I recently signed-up for pinterest. I wasn’t actually interested in signing-up, but wanted to see what their sign-up process looks like. If you’ve read one of my previous posts, you’d know I nearly always use unique, unpredictable email addresses for new services I sign-up to. Pinterest registration is quite nice, and only asks for a few details and an email address (that is, if you prefer a username and password instead of using Facebook or Twitter to login). Once you enter the details, pinterest sends you a Please verify your email message to your inbox. So far, so good.

However, what happens if you don’t verify your email? As was the case here. I wasn’t actually interested in creating an account. I assumed that I won’t hear from pinterest again. Wrong. I just received an email from pinterest, announcing their new secret boards. So much for confirming my account. According to Spamhaus, this is considered unconfirmed opt-in which is categorized as spam.

To add insult to injury, if I try to opt-out from the email I just received, Pinterest asks me to login to my (unconfirmed) account. These are all small annoyances, I know. But is it really that difficult to do things right? An unconfirmed account should not receive any messages. Opt-out links should just be one click and that’s it.

monitoring python Security Technology

Statsd and Carbon security

Post author By Yoav Aner
Post date 26 August, 2012

I’ve written about installing and using Graphite and it’s a really great tool for measuring lots of kinds of metrics. Most of the guides online don’t touch on the security aspects of this setup, and there was at least one thing that I thought should be worth writing about.

How are we measuring

Metrics we gather from our applications have the current characteristics / requirements:

We want to gather lots of data over time.
Any single data-point isn’t significant on its own. Only in aggregate.
Measuring is important, but not if it slows down our application in any way.

Security Technology

Rackspace ate my homework pt. II

Post author By Yoav Aner
Post date 23 August, 2012

For those who followed my previous post, I thought I should post a quick update.

Something positive

I was naturally quite surprised to be contacted rather quickly by Rackspace shortly after posting. This was a nice surprise, and the contact afterwards were somehow more understanding. At least I could sense they are feeling sorry for my situation.

Lost homework

As expected, there was no way to recover the lost image. I received a follow-up message on the original ticket confirming this quite clearly. They then rather swiftly changed the tone into legal-speak and referred me to their terms of service, which I quote here for the benefit of the world at large.

Security Technology

Rackspace ate my homework

Post author By Yoav Aner
Post date 22 August, 2012

One of the greatest promises of cloud computing is resilliency. Store your data ‘in the cloud’ and access it from anywhere, enjoy high durability and speed. You know the marketing spiel already. A recent incident reminded me the importance of backups. In fact, the importance of backups of backups. Sounds strange? of course. This is the tale of a missing server image.