[001] Introduction + Installing Elixir

A quick introduction to the screencast, followed by an Erlang / Elixir installation walkthrough.

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Introduction + Installing Elixir [05.13.2016]

Hello, and welcome. I'm Josh Adams, and I'm happy to introduce you to Elixir Sips - a new screencast series that will walk through learning Elixir from the ground up, and will move on to more advanced topics within Elixir as time goes on and we all get better with the language.

What is Elixir and why are you interested in learning it?

In the words of the Elixir website, Elixir is a functional, meta-programming aware language built on top of the Erlang VM. It is a dynamic language with flexible syntax and macro support that leverages Erlang's abilities to build concurrent, distributed and fault-tolerant applications with hot code upgrades.

In general, I find it interesting because of three things:

  • I find the Actor Model of computation very compelling, and Erlang's where it's had the most time to grow.
  • Being built upon the Erlang VM, it should be possible to write extremely reliable, distributed, concurrent systems in it.
  • The syntax is far more approachable for beginners than is Erlang's syntax.

These three points combined should lead to a massive growth in the language, and I'm excited about that.

Who am I and why am I qualified to take you along as I learn it?

My name is Josh Adams. I'm the CTO of a software development consultancy, Isotope11. I'm an expert Rubyist and a highly proficient JavaScripter, and I've built financial systems that handle billions of dollars worth of transactions each year. That's about all of the horn-tooting I'm comfortable doing. The point is, I've finally gotten to the point in my career where I feel comfortable saying that I'm quite good at what I do.

However, Elixir qualifies firmly as something I don't do - at least yet. I've only very recently begun learning Erlang itself. However, I've built a currency trading platform that is based on the Actor Model in Ruby, using the Celluloid ecosystem that Tony Arcieri wrote. Consequently, I'm pretty firmly comfortable with building large systems using the actor model, but I'm also pretty much a rookie when it comes to Elixir.

I think that places me in an ideal situation to be useful in teaching people Elixir, by them following along as I learn it.

Assuming you're convinced by all of this, let's get started learning.

Installing Erlang

The only prerequisite for installing Elixir is Erlang, since Elixir runs on the Erlang VM.

Installing Erlang is exceedingly simple. There are instructions and downloads available at the main Erlang site, but I think the easiest way to get started is to download a precompiled package provided by the fine folks at Erlang Solutions.

There are downloads for various operating systems there. Since I use Ubuntu Linux, I'll just walk through the installation procedure on my machine. If you're on a Mac or Windows, just download and install the provided package and skip to the bit where we verify that the installation worked.

First, I add a file with the ppa to /etc/apt/sources.list.d/erlang.list:

deb http://binaries.erlang-solutions.com/debian raring contrib

Next, download and add the Erlang Solutions public key to the apt keyring:

wget -O - http://binaries.erlang-solutions.com/debian/erlang_solutions.asc | sudo apt-key add -

Then update my list of available packages:

sudo apt-get update

Finally, install the erlang release that is provided in that ppa:

sudo apt-get install esl-erlang

You can verify that the installation worked by entering an Erlang Shell. At a console prompt, type erl and you should be greeted by something that looks like this:

Erlang R16B01 (erts-5.10.2) [source-bdf5300] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false]

Eshell V5.10.2  (abort with ^G)
1> 

If you see that, congratulations - you've installed Elixir's entire prerequisite list. Type q(). and press Enter to exit.

Installing Elixir

There are various precompiled packages, but it's very easy to build Elixir from source. I'm going to build it from source, but feel free to download a package if that's your preferred way to get software onto your system.

First, download the latest stable release of Elixir at the elixir github repository's tags page. At this moment, that's v0.10.1.

Go ahead and uncompress the download wherever you prefer to keep your source files. Then, cd into the Elixir directory.

Finally, just run make and Elixir will be built. You'll end up with some binaries in the bin directory. The suggested next step is to add that directory to your PATH. Personally, I just do a sudo make install and install them in the appropriate location for binaries on my system.

Firing up iex

To verify that your Elixir install was successful, type iex. Assuming you did everything right, you should be greeted with a prompt that looks like this:

$ iex
Erlang R16B01 (erts-5.10.2) [source-bdf5300] [64-bit] [smp:4:4]
[async-threads:10] [hipe] [kernel-poll:false]

Interactive Elixir (0.10.1-dev) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)> 

Just press Ctrl+C twice to close the shell out.

That's it, you've successfully installed Elixir. See you soon.

Where can you get more help with Elixir?

  • There's an IRC channel: #elixir-lang on FreeNode
  • There's a Google Groups mailing list called elixir-lang-talk
  • The Elixir Website is extremely well done and has lots of nice information.

Notes on installing on Windows

A nice subscriber, Greg Houston, sent in some notes on installing under Windows. I'm adding them to this episode's notes for posterity. Thanks Greg!

Here are some notes on the Windows install... 1) Use the prepackaged binary for Erlang. The installer works great. 2) You have to manually add the bin folder for Erlang to your PATH environment variable. 3) The prepackaged binary for Elixir is a zip file you have to manually unzip. I unzipped it to C:\Program Files\Elixir 4) You have to manually add the bin folder for Elixir to your PATH environment variable.

Notes on installing on Mac

Another nice subscriber, Errin Larsen, sent in some notes on installing on a Mac. There are Homebrew packages available for Erlang and Elixir.

From Errin:

  • brew install elixir is broken - I used brew edit elixir and followed this commit's changes to fix the problem

What is the Actor Model?

I had a subscriber ask me for a succinct explanation of the Actor Model. Without getting too deeply into it, I'd describe it thusly:

An actor is an object that has its own lifecycle and lives concurrently. An actor communicates with another actor by placing a message in his mailbox. The second actor can then read the mailbox in his preferred order, and respond to the messages at his leisure. This is a large part of the Erlang 'shared nothing' model, and one of the core concepts that leads to its fault tolerance and ease of distribution.

If you want more details, there's an excellent video that MSDN's Channel 9 did interviewing Carl Hewitt, Erik Meijer, and Clemens Szyperski on the actor model.