ariejan.net

I'm here for an argument

Mon, 25 Mar 2013 16:00:00 PDT

When people make a request or proposal I often see them present their request and arguments using the following structure:

Make a request
Give a plethora of arguments why that request is a good idea.

An example:

I want to go to the zoo!
Because I want to see animal
Because I want to spend time with you
Because it has been a long time

Here I think, meh, the zoo. And then I read some arguments that may or may not change my opinion on actually going to the zoo or not.

You start with the what and then continue on to the why, but I’ve already lost interest.

Consider this request:

I want to spend time with you and see animals.
It has been a long time since we went to the zoo
Let’s go to the zoo!

Here you start with me agreeing on spending time together and it becomes easier for me to accept your request to go to the zoo. I’m not blinded by your request.

You start with the why and then continue to the what.

In addition to this article, please watch Simon Sinek’s TED Talk [18m05] How great leaders inspire action.

Automated nanoc deployments

Sun, 24 Mar 2013 16:00:00 PDT

I’ve migrated ariejan.net from a custom Ruby on Rails application to a statically generated site with Nanoc.

Publishing my site now goes like this:

Write stuff in Markdown
Commit and push
Watch how jenkins builds and publishes the site with nanoc and rsync.

Using nanoc

Nanoc is a very powerful static site generator. You can use ruby to create helpers, filters and what not. Fancy using Sass, Compass and Haml? No problem!

Simply write pages in Haml or Markdown and Nanoc will generate a complete site, including sitemap, robots.txt and RSS feed.

Once you’ve set everything up to your liking, simply run nanoc compile and your site is ready.

Nanoc also has some nice features to deploy your website through rsync, which will upload (or remove) files on a remote server as necessary.

Automate the crap out of it!

I’m a programmer. I like to automate repetitive tasks. So I did.

I’ve setup Jenkins with the RVM plugin and that’s all I need to have Jenkins generate and deploy my Nanoc site.

Here’s the build script I currently use:

#!/bin/bash
export NANOC_ENV=production
bundle install
nanoc compile
nanoc deploy -t public

If the compilation fails for some reason, the deployment is cancelled.

Enter gitlab

Now I use Gitlab to host tons of private repositories, including the one for ariejan.net.

I’ve setup a web hook that will trigger the Jenkins job when new commits are made or pushed.

This allows me to quickly edit a file, commit it and Gitlab en Jenkins will make sure the change is compiled and published to ariejan.net.

Where to go from here

For now, this setup suffices for me. I keep all my posts in version control, and backupped to S3 (by backing up my gitlab repositories). Adding a new story to git is sufficient for it to be published automatically on ariejan.net and in the event something goes wrong with compilation, Jenkins will notify me of the build failure.

Review commits in your feature branch

Thu, 07 Mar 2013 15:00:00 PST

Github pull requests are awesome, but you can’t use them all the time, mostly when working on code not hosted at github.

The following snippet makes it easy to see the commits in your current (head) branch that are not yet in the base branch.

To see what commits are made in your current feature branch, but which have not been merged into develop yet:

1
2
3

$ gpr develop
* 5246248 <ariejan@ariejan.net> (HEAD, origin/feature-branch, feature-branch) Implements the awesome feature (50 minutes ago)
* 4f55b7c <ariejan@ariejan.net> Write specs for awesome feature (2 hours ago)

Snippets

To achieve this, add the following alias to ~/.gitconfig:

1 2	[alias] lg = log --graph --pretty=format:'%Cred%h%Creset %Cblue<%ae>%C(yellow)%d%Creset %s %Cgreen(%cr)%Creset' --abbrev-commit --date=relative

And the following alias to your ~/.bashrc or ~/.zshrc:

1	alias gpr="git --no-pager lg HEAD --not $1"

Bonus tip

After reviewing the commits in your feature branch with gpr, use hub to attach your code to a github issue:

1	hub pull-request -i 42 -h ariejan:feature-branch -b you:develop

Instagram, Governments and Cypherpunks

Mon, 17 Dec 2012 15:00:00 PST

The whole internet collectively fell over Instagram earlier this week when they released their new Terms of Service.

Some or all of the Service may be supported by advertising revenue. To help us deliver interesting paid or sponsored content or promotions, you agree that a business or other entity may pay us to display your username, likeness, photos (along with any associated metadata), and/or actions you take, in connection with paid or sponsored content or promotions, without any compensation to you.

Today Instagram officially responded to all the screaming and shouting, trying to control the damage.

From the start, Instagram was created to become a business.

Well, that was unexpected. It’s the same with Facebook, Twitter, Gmail, Hotmail, etc. All these services are here for you to use for free - awesome!

But nobody ever got rich from giving stuff away for free, and these are businesses we’re talking about.

Let’s see how this works over at Facebook.

Exhibit A: Facebook

Facebook is a good example of how you are the product being sold. We all know Facebook tries to show you ads that you are likely interested in. Based on what you put in your profile advertisers can target specific audiences.

That might sound all well and good to you, but did you also know that your friends might see a sponsored post in their newsfeed? And that that sponsored post appears as if it’s one posted by you?

Here you see a post by a friend of mine who apparently likes some mobile company’s ad. They didn’t like this add. I asked them.

So basically Facebook and an advertiser are using you, your name and your profile picture to promote an advertisement to one of your friends.

Exhibit B: Google

Another example, more in line with Facebook, is Google. All those free tools: Search, Gmail, Google+, Analytics, Web Master Tools, maps. They are all geared towards either exposing ads to you, or gathering data on you to expose more focussed ads.

The plus side here, I would say, is that Google actually delivers usable services, like search, mail, calendars and such. But still, look at the boatloads of money Google is making selling ads based on your private details and online behaviour.

Exhibit C: Twitter

Twitter is a company that has struggled for a long time to find a way to monetize itself. Hopes were high that they would find a new an innovative way, but they have not.

It remains to be seen what’s going to happen exactly with twitter, but we can all assume that our tweets are being analyzed and that Twitter will do anything to sell you to their advertisers.

Exhibit D: Instagram

To come back to Instagram, they’re in the same boat as Twitter and Facebook.

They have been growing their user base for quite some time now and now comes the time to move in and cash on all those users.

The new terms of service should not come as a surprise.

Instagram wants to use your data to match you up with advertisers and it even wants to show ads endorsed by you, just like Facebook already does.

So what’s happening out there?

Social Media are nice, they connect people and can start revolutions. But that is not why those media exist. They are marketing and data mining platforms on a massive scale.

Have you ever wondered why social media companies get multi million dollar investments? Because with a huge, world-wide user base, there is a huge advertising potential.

If you are not buying a product or service, but are receiving one for free, then you are the product or service begin sold.

I think that companies like Facebook and Instagram are wading in a gray area of privacy. Their practices may be perfectly legal, but they are ethically questionable.

On government spying and eavesdropping

You might sometimes worry about governments eavesdropping and keeping tabs on innocent citizens – and you should.

If you look at the sheer amount of data social media gather on you, imagine what kind of data a government agency with the proper tools and hardware can do.

But the issue is not really that companies and governments are gathering data - you are feeding it to them with every status update and photo you upload to the internet. With every email you sent.

So, what’s to be done?

Cypherpunks to the rescue?

Now, I won’t claim to know a whole lot about cypherpunks and the crypto wars, but these people have fought (and still are) fighting for our digital rights and freedom.

We are collectively giving away our personal data to companies and governments and most of the time we don’t even know it. But then some image sharing company changes its terms that will allow them to display adds alongside your name and we freak out.

Here’s quite from the Cypherpunks manifesto:

Privacy is necessary for an open society in the electronic age. … We cannot expect governments, corporations, or other large, faceless organizations to grant us privacy … We must defend our own privacy if we expect to have any. … Cypherpunks write code. We know that someone has to write software to defend privacy, and … we’re going to write it.

To be clear, I’m not a cypherpunk by any means. Here’s a snippet from Wired magazine, 1993:

The people in this room [cypherpunks] hope for a world where an individual’s informational footprints – everything from an opinion on abortion to the medical record of an actual abortion – can be traced only if the individual involved chooses to reveal them;

And this is where the problem lies. Yesterday Will Wheaton, of Star Trek fame, wrote about this as well.

Will has a great point that we’ve come to a point where it’s okay that somebody else shares your personal details with a third party on the internet – without your knowledge, without your consent. And there is nothing you can do about it.

I’m not sure about you, but this sure frightens me.

Binary debugging with git bisect

Wed, 28 Nov 2012 15:00:00 PST

Part of resolving a bug is finding where and when that bug was introduced into your code. Not so much for blaming a specific person, but more for an understanding of how and maybe why the bug was introduced; and more over which versions of your app are affected.

Most of the time the bug was recently introduced and your CI notified you that stuff has been broken.

In order to find out when, how and by whom the build was broken, you’ll have to dig into your git history and run your specs to see if they pass or not.

Running your specs for every commit in your history manually is very time consuming and boring. Luckily there are better ways, using plain old git.

Binary search

Before I dive into git, it’s important you understand how binary search works. If you already know this stuff, skip right to the next section.

You have a sorted array. This means there is some order to the elements you have. Presume you have an array of ints:

1	a = [1, 3, 4, 7, 33, 42, 54, 76, 89, 91]

Now, we want to find the position (n) of 7 in this array using binary search so that a[n] == 7.

Binary search uses a divide and conquer strategy. You split the array in the middle. We have 10 elements, so a logical place would be to split the array at position n = 5, which has the value 42.

Comparing 7 <=> 42 tells us that, because we have an ordered array, the value 7 should be in the first half of the array.

We can ignore the right half of the array for searching, and repeat this step for the left part, specifically:

1	[1, 3, 4, 7, 33]

So, let’s split this part up again. We get 4. This is less than 7, so if we continue looking we should take the right part.

[7, 33]

Okay, again, we continue our search. We know have to split the array one way or the other, and we end up picking n = 4. We hit 33. Surely the value of 7 must be on the left part of this.

Note that although I don’t show the whole array, I’m still using the index positions for the entire a array.

[7]

Now, there’s not much to pick for us. This is 7. Right here at n = 3. Done!

Notice that the last step does not involve checking the value of the last element. We only have 1 element left, so we’re finished.

If we had been looking for a value of 18, we would have also found n = 3. This means that we can search for non-existing values, which then return the index right before where that number should be inserted. This works because the array was ordered, so we can safely make such assumptions. Nice, huh?

How does binary search relate to finding bugs?

Well, in the example above we were looking for an integer value. The test we use to evaluate is simple:

1	value <=> a[n]

When we want to find the commit that broke our build we need a more clever way of comparing values.

This is where your test suite comes in. You have a failing spec now, so basically we’re looking for the point in git history where that spec failed for the first time.

Git bisect

Because it’s not feasible to do a linear search over your entire commit history, we’ll have to start by marking a good and a bad commit.

First we’ll have to find a location in your git history where you know the app did not exhibit this bug.

More than likely, this place is your last stable release. If you used git tag to tag your release, you should be able to find out quickly if that release contains the bug.

git checkout v1.2.1
rspec spec/features/fancy_spec.rb
=> 0 failures

Good. We now our latest commit was broken, so let’s get started with that binary search!

You don’t have to keep track of the git history and binary search position all by yourself: git does this for you. All you have to do is compare each commit that is presented to you with an expected result. E.g. does the fancy_spec.rb spec pass or not?

Bisecting steps

First, let git know you want to do a binary search.

git bisect start

Next, let git know which commit is good, and which one is bad.

git good v1.2.1
git bad e8ab31

Git will respond with something like this:

Bisecting: 19 revisions left to test after this (roughly 4 steps)
[0e70ee6aefe428fa897ec7e48273c3fe4d0bf7fb] Did some funky stuff in `config/application.rb`.

Git has determined that commit 0e70ee is right in between v1.2.1 and ebab31. Check if this revision is broken and report back to git.

rspec spec/features/fancy_spec.rb
> 1 failure
git bisect bad

And git will respond:

Bisecting: 9 revisions left to test after this (roughly 3 steps)

You can continue this until git tells you the commit that first broke this spec.

When you’re done bisecting (or if you just feel like doing something else), just tell git:

git bisect reset

Usage in the field

Git bisect is a very powerful tool to find specific points in your code.

In this example we were looking for a commit that broke a specific test. You can look for all kinds of things:

When did the layout on that page break?
At what point did we upgrade that gem to a buggy release?
Who added this ugly piece of code?!

Doing a binary search over your git history is a fast and efficient way of finding these kind of things out.

CustoMac

Wed, 21 Nov 2012 15:00:00 PST

Ever since Apple decided to put Intel processors in their Macs there have been attempts by enthusiasts to run Mac OS X on commodity hardware – with mixed results.

The key to installing Mac OS X on a non-Mac computer is using the right hardware. If your hardware is a close to Apple kit as possible, you have the best chance to succeed.

The so-called Hackintosh community has come a long way the past few years in making it easy for “normal people” to install Mac OS X on their PC.

Since I was tired of using Debian Linux on my Desktop, dual booting to Windows to play the occasional game of World of Warcraft, I decided to give installing Mac OS X a try. But there was a problem.

The hardware

My current PC is powered by an AMD processor (AMD Phenom II X6 1055T, to be precise). Simply put, installing Mac OS X on an AMD cpu is not going to work.

So, the first thing I did was go over to the OSx86 Project Hardware Compatibility List and see what hardware is most compatible with Mac OS X 1.8.2 (the most recent version of OS X at this time).

I already knew I’d need a shiny new Intel CPU, and thus also a new motherboard.

Choosing a CPU

Choosing a CPU for your CustoMac is not very difficult, because you are limited to Intel. Since the release of the new MacBooks Apple officially supports the Ivy Bridge architecture, which means about a 50% lower power consumption and a 5-15% speed increase (link).

The main candidates were:

Intel i5 3570
Intel i5 3570K
Intel i7 3770K

I won’t go into to too much detail here, but I chose the Intel i5 3570.

The i7 offers Hyper Threading at a price bump of about € 100,-. For me, this was not worth the money.

Then there’s the choice between the 3570 or the 3570K. The ‘K’ version has less features, but is unlocked, allow it to be easily over-clocked to higher speeds.

The price difference between the 3570 and the 3570 are minimal, but I’m not planning to over-clock my CPU, so I went for the slightly cheaper Intel i5 3570 processor.

Choosing a motherboard

Next came a more difficult decision. The motherboard. Again, the Hardware Compatibility List was a great help here. In the end I chose the Gigabyte Z77-DS3H.

The pro’s of this board are that it’s well supported by Mac OS X and the OSx86 community. This board is special because it features Gigabyte’s 3D UEFI Bios. This bios would make it easy to install Mac OS X untouched on your machine.

I didn’t end up using this UEFI feature, but nonetheless, support for this board is incredible.

The full hardware list

So, recycling other parts of my current PC I build the following CustoMac configuration:

Gigabyte Z77-DS3H Motherboard (But at Amazon)
Intel i5 3570 CPU @3.4Ghz (Buy at Amazon)
16GB RAM at 1333Mhz
1x 120 GB OCZ Agility 3 SSD
1x 1TB Western Digital HD
1x 2TB Western Digital HD
XFX ATI Radeon HD 6870 1GB (Buy at Amazon)

Note 1: The above Amazon links are affiliate links.

Note 2: I could have upgraded my memory to 1600Mhz units, which would be faster. But I have no use for the old memory, so I chose to re-use it for now.

The preparation

Before you get started, you should prepare an installation USB drive on another Mac. You’ll need at least 8GB of space on the drive.

Buy Mountain Lion from the App Store on you Mac and download the installer. If you already purchased Mountain Lion, re-download it.
Download UniBeast for Mountain Lion and follow step 1 and 2 from this guide.

At this point you have a bootable USB drive with the Mountain Lion install on it.

To prepare the actual installation, remove any devices you don’t need, like extra hard drivers, DVD/BluRay drives, etc. In my case I also pulled out the ATI 6870 and used the onboard Intel HD Graphics during installation.

Plug your USB drive into a USB 2.0 (black, not blue) port on the motherboard. Make sure to use one of the ports on the back of your computer, those are directly attached to the motherboard and have the greatest chance of succes.

Now, boot up the computer and enter the BIOS. There are two important changes you need to make.

Set SATA to AHCI mode.
Disable VT-d.

Then select the USB drive as the bootable device and boot.

Booting the installer

You’ll see the UniBeast boot screen which show a ‘USB’ option (and possibly other, depending on what’s on your disks). Choose ‘USB’ - but don’t press ENTER just yet. Instead, type -x, which will show up on the screen. Then, press ENTER.

After a few minutes you should have the Mac OS X Installer in front of you. Go ahead, install this baby.

Notes on Fusion drive

It’s possible to create a CustoMac Fusion Drive using an SSD and regular harddisk.

When you’re in the installer, choose ‘Terminal’ to open a terminal window and follow the steps in this fusion drive guide.

I was able to create and install Mac OS X on a Fusion Drive without problems. The only knack was that the custom bootloader you need is not Fusion Drive aware, which makes it difficult to use.

In the end I decided to not use a Fusion drive setup, and just install everything on the SSD.

Completing the installation

Now comes the tricky part. The installation is done and you’re CustoMac wants to reboot. Let it, but leave the USB drive connected.

Your machine will boot up with the same boot menu as before, but instead of ‘USB’ you should now be able to select ‘Macintosh HD’.

Select that, enter -x followed by ENTER.

You’ll now be taken through the final steps of installation, like setting up iCloud and creating a user account.

When finished, you should be on your new Mac desktop.

Installing custom kexts

Now, your CustoMac can only boot with the USB drive. Let’s change that by installing a bootloader and some kernel extensions.

Download MultiBeast for Mountain Lion.
Run the installer and select the following options: ** UserDSDT or DSDT-Free Installation ** Miscellaneous => FakeSMC ** Audio => Realtek ALC8xx => Without DSDT => Latest version for ALC8887/888b. ** Network => maolj’s AtherosL1cEthernet ** Disk => TRIM fix for 1.8.1+ ** Bootloaders => Chimera

That’s all. Install that stuff. Now, you should be able to reboot your CustoMac and boot it without the USB drive.

If things don’t work out (like a black or white screen, kernel panics, whatever), just plugin your USB drive again, boot from it and select your ‘Macintosh HD’.

Graphics

At this point, you should have a working CustoMac with sound and network working. The only thing missing is a proper graphics card.

You’ll need to make some tweaks to the chameleon plist file. Then shutdown your computer and install the graphics card.

Note: this works for my XFX ATI Radeon HD 6870 card. There may be subtle differences for different version and brands. Just use the Google to find hints, boot with the USB drive to get to your system and make updates as needed.

In /Extra/org.chameleon.Boot.plist make sure you have the following entries:

<key>AtiConfig</key>
<string>Duckweed</string>
<key>AtiPorts</key>
<string>5</string>
<key>Graphics Mode</key>
<string>1920x1080x32</string>
<key>GraphicsEnabler</key>
<string>Yes</string>
<key>PciRoot</key>
<string>1</string>

Depending on which slot you used for your graphics card, you may have to set PciRoot to 0.

I also had to add npci=0x2000 to Kernel Flags, but you may or may not need it.

<key>Kernel Flags</key>
<string>npci=0x2000 darkwake=0</string>

Boot up!

Now, reboot one last time and everything should go smoothly.

If your system comes up without any troubles, start attaching those others disks and drives you had disconnected during the installation. There shouldn’t be any issues here.

You’re done!

Congratulations. You now have a CustoMac!

Keep in mind that you should not blindly install any update you see. Installing an update my change the bootloader or change kernel extensions that break your system.

A good tip is to create a full disk image of your SSD using a tool like Super Duper. In case of shit hitting the fan after an update, you can easily restore your disk to working order.

In my case, I’ve attached an old 500GB drive to store this disk image. It works great.

Shiny and fast!

Just as a side-note, my CustoMac is blazingly fast. It’s the combination of the fast Ivy Bridge architecture, the i5 processor, and the SSD.

I’ve measured boot-up time from pressing the power button to the Mac OS X login screen at about 11 seconds.

A Call to all CI Service Providers

Sun, 04 Nov 2012 15:00:00 PST

As a professional developer I test my code. Every check-in I do is tested either on Kabisa’s Jenkins server or on Travis CI Pro.

For open source projects there’s Travis CI. It’s free and a great way to get to know Travis.

Now, as an individual I have some side projects, most notably my own site, Ariejan.net. I value well written and well tested code as much for my own stuff as for my professional work. However, I don’t have a Jenkins CI server in my basement.

Looking around the internets there are a few CI services that can test my Ariejan.net Rails application, among them Cirlce CI, Atlassian Bamboo and Semaphore.

Now, the thing here is that to test the few projects I have (about four) it will cost me more to have the hosted in a CI services than actually running these apps.

Travis - $129/mo for 2 concurrent builds.
Circle CI - $49/mo for 10 private projects.
Semaphore - $39/mo for 5 private projects.
Bamboo - $20/mo for 10 jobs.¹

¹ Bamboo advertises $10/mo, but a $10/mo Jira subscription is also required.

As an individual, these prices are pretty steep for the few commits I make during the weekend.

Looking at Github and Heroku

Let’s take a look at github and heroku here. At heroku I pay nothing to host a site. Performance is limited, but it more often than not is sufficient for a side-project. Adding a worker or extra dyno costs about $38/mo. Still less than half of the CI services I mentioned.

Having private repos with Github is also quite cheap. You’ll get 5 for $7/mo. Which, converted, is about €1 per repo a month.

Now, as an individual developer, I’m more than happy to use these services for these relatively low fees.

Where are the cheap, individual CI services?

As an individual developer, this is what I need:

Unlimited, or at least 5-10 jobs/private projects.
Low monthly cost: $5 - $10.

What I don’t need is:

Concurrency and paralellisation
Immediate execution
24/7 Support

I can do with a single worker doing one build at a time. I don’t write enterprise CRM software in my weekends, you know.

Also, I don’t expect my build to execute immediately. I don’t mind if there’s a job queue and I have to wait a bit longer to get back results.

Business opportunity?

IMHO there’s a business opportunity here. Github and Heroku are great examples of how giving something away for free (or cheap) to individual developers creates a market for their product.

I understand that CI takes a considerable amount of system resources and time, but having a good experience as an individual is more than likely to attrack people to your platform when they need a more profession plan.

Who’s stepping up to the plate?

Decorating Sorcery's current_user with Draper

Thu, 01 Nov 2012 16:00:00 PDT

I already wrote about how to apply your decorator to the current_user when you’re using Devise. However, the trick is a bit different when applied to Sorcery.

Instead of being nil when no user is signed in, Sorcery uses an explicit false value, no nil. In your ApplicationController at app/controllers/application_controller.rb add this:

1
2
3

def current_user
  UserDecorator.decorate(super) unless super == false
end

I’m using the most recent version of Draper by the way.

A static file server in Go

Wed, 03 Oct 2012 15:00:00 PDT

If you don’t know Go, you should really look into it. Today I was trying to figure out how to write a simple (and fast) static file server in Go.

As it turns out, this is very easy to do. Go contains (in the net/http package) a nice FileServer type that can server files from the directory you point it to.

Here’s a sweet and short example:

package main

import (
    "net/http"
    "log"
)

func main() {
    err := http.ListenAndServe(":4242", http.FileServer(http.Dir("public")))
    if err != nil {
        log.Printf("Error running web server for static assets: %v", err)
    }
}

By itself this is not very useful, but you can easily integrate this into any other http server you create, maybe for handling dynamic requests or doing web sockets.

Migrate git repositories

Sun, 30 Sep 2012 15:00:00 PDT

Sometimes you have to move your git repository to another host. In this case I want to move a privately hosted git repository to a brand spanking new github repository.

These are four easy steps to get that done:

$ git clone --bare git@yourserver.com:project.git
$ cd project.git
$ git push --mirror git@github.com:ariejan/project.git
$ cd .. && rm -rf project.git

That’s it. Don’t forget to update the remote of your working copy accordingly:

$ git remote set-url origin git@github.com:ariejan/project.git

Of course, this works with any git server or service, not just Github, although Github is awesome and you should use it.