I've been on the fence about Phoenix and Elixir for a while and I thought I'd take at least a quick dive. I've had a development system for Phoenix and Elixir since at least 2016 but I haven't done much. This means that the first task is bringing it into the 2020s.

Upgrading Elixir

I installed Elixir via HomeBrew which means it is a simple:

which elixir

Note: It can be hard sometimes to know if you installed things via HomeBrew and checking their location is an easy cheap as HomeBrew installs stuff to /usr/local/bin

And then:

brew upgrade elixir

And then:

elixir --version
Erlang/OTP 23 [erts-11.0.3] [source] [64-bit] [smp:16:16] [ds:16:16:10] [async-threads:1] [hipe] [dtrace]

Elixir 1.10.4 (compiled with Erlang/OTP 23)

You can also use just -v:

elixir -v
Erlang/OTP 23 [erts-11.0.3] [source] [64-bit] [smp:16:16] [ds:16:16:10] [async-threads:1] [hipe] [dtrace]

Elixir 1.10.4 (compiled with Erlang/OTP 23)

Upgrading Mix and Hex

Mix and Hex give the equivalent of a build tool (like Rake from the Rails world) and a Package Manager (like Gem / Bundler).

To upgrade mix, you use:

mix local.hex
Found existing entry: /Users/sjohnson/.mix/archives/hex-0.20.5
Are you sure you want to replace it with ""? [Yn] Y
* creating /Users/sjohnson/.mix/archives/hex-0.20.5

And that will upgrade both mix and hex.

Upgrading Phoenix

The phoenix framework version I have dates back to 1.2 or 1.3 I think. The first step is to figure out what version I have:

mix --version
Phoenix v1.3.3

The method to upgrade the Phoenix framework itself is:

mix archive.install hex phx_new 1.5.4

I used a google query to discover that the current Phoenix framework version was 1.5.4. The other way to find this version number is to go to this url:

And then look at the drop down of different versions in the left hand sidebar. The latest version is always at the top.

Creating a Sample App

My first step was to create a location to work on Phoenix apps. I'm going to be experimenting with a version of my JobHound app written in Phoenix so I created this directory:

mkdir -p /Users/sjohnson/Sync/coding/jobhound/phoenix

I can then move my existing Rails source code into:


and be able to open both code bases in the same editor window which should facilitate copy and paste based code rewriting.

With all the tooling updated, creating a new Phoenix app is as a simple matter of:

cd /Users/sjohnson/Sync/coding/jobhound/phoenix
mix jobhound

You should see a bunch of output looking like this:

* creating jobhound/config/config.exs
* creating jobhound/config/dev.exs
* creating jobhound/config/prod.exs
* creating jobhound/config/prod.secret.exs
* creating jobhound/config/test.exs
* creating jobhound/lib/jobhound/application.ex
* creating jobhound/lib/jobhound.ex
* creating jobhound/lib/jobhound_web/channels/user_socket.ex
* creating jobhound/lib/jobhound_web/views/error_helpers.ex
* creating jobhound/lib/jobhound_web/views/error_view.ex
* creating jobhound/lib/jobhound_web/endpoint.ex
* creating jobhound/lib/jobhound_web/router.ex
* creating jobhound/lib/jobhound_web/telemetry.ex

This created the canonical structure for a Phoenix app:

See Also