Zero to Heroku

John Baylor experiments

I’ve just moved my TwitterBot from Ruby/Rails to Elixir/Phoenix and I tend to always miss a step, so here is the process, which is a mix of the Phoenix deploy-to-Heroku page and the Heroku not-officially-supported reference:

Create the new Phoenix app: mix phx.new zero_to_heroku --no-ecto --module ZeroToHeroku (note: it is extra-simple without LiveView or a database - YMMV
but if you leave out the --no-ecto then I have you covered, below)
cd zero_to_heroku
git init .
Update .gitignore to include /.idea (the Rubymine Dir) and /junk (where I move random files that I’ll likely never need again):
```
echo "/.idea" >> .gitignore
echo "/junk" >> .gitignore
```
Update .tool-versions to configure asdf with the in-use versions of erlang, elixir, and node (node is used for compilation of client-side assets, also called “static assets”). Here is mine right now:
```
nodejs 14.3.0
elixir 1.10.3-otp-23
erlang 23.0.1
```
Use asdf install to ensure we’re using the correct versions.
Create the app on Heroku with heroku create zero-to-heroku (note that one has to use dashes instead of underscores)
If app creation succeeds on Heroku then your server will be on zero-to-heroku.herokuapp.com so you can now add that host in the config/prod.exs file. Without it, the websocket connection will fail.
Tell git how to connect to Heroku: heroku git:remote --app zero-to-heroku
Tell Heroku how we want it to start up our application: echo 'web: mix phx.server --no-halt' > Procfile (--no-halt tells it to ignore some stop signals)
Tell Heroku how to run our code by specifying a few buildpacks. First, tell Heroku to use prebuilt binaries by installing the hashnuke buildpack:
```
heroku buildpacks:set hashnuke/elixir
```
And then configure this buildpack by setting elixir_buildpack.config to specific language versions you’ve been using. Mine:
```
erlang_version=23.0.1
elixir_version=1.10.3
```
Finally, tell Heroku to use node.js to build static client assets, such as to convert SCSS to CSS, minify JavaScript file, etc., by installing the phoenix-static buildpack:
```
heroku buildpacks:add https://github.com/gjaldon/heroku-buildpack-phoenix-static.git
```
And configure this buildpack with via the phoenix_static_buildpack.config file, containing your node version:
```
node_version=14.3.0
```
Add everything to git: git add * .gitignore .tool-versions .formatter.exs

Add the necessary Phoenix environment var:

heroku config:set SECRET_KEY_BASE=`mix phx.gen.secret`

Deploy with git push heroku master
Note that if you chose, on app creation, to use a database (omit the --no-ecto part of the command) then this deploy will probably fail with a DATABASE_URL error. Running heroku addons:create heroku-postgresql should build a database for it and set the missing DATABASE_URL value.
Go to the newly-created URL: https://zero-to-heroku.herokuapp.com/ for me.
At this point, you should see the page
Profit!

Addenda

2020/08/16: I just noticed that I never mentioned ecto.create or ecto.migrate in the original instructions - which is nice to see - it validates that the focus was on getting to heroku, not any iterating on your local dev machine.

Addenda

Related Posts