Preview deployments

[airtonix]

Deployment to static named environments (dev/stg/prod) I can understand since the configuration used for those would probably be separate kamal config files.

but what about dynamic named environments (aka preview environments), like the kind of thing you'd trigger from a PR ?

1. Is anyone doing this?
2. Are people just generating a kamal config file before deploying? or can kamal interpolate the host name from environment variables?

Example

config/deploy.previewyml

service: hey
image: 37s/hey
servers:
  - 192.168.0.1
registry:
  username: registry-user-name
  password:
    - KAMAL_REGISTRY_PASSWORD
builder:
  arch: amd64

host: pr-$PREVIEW_ID.dev.example.com

env:
  secret:
    - RAILS_MASTER_KEY

Then in github actions

env:
  PREVIEW_ID="${{ github.event.pull_request.number }}"
run: kamal deploy -d preview

I'm curious to know how people are thinking about approaching this scenario

[nickhammond]

@airtonix I haven't tried out this approach specifically but this blog post will probably give you some ideas(not mine) https://guillaumebriday.fr/deploying-review-apps-automatically-with-kamal-on-ci-cd#5-configuring-the-review-app-destination

You should be able to utilize ruby and load in a ENV value into your deploy recipe.

[airtonix]

When you say "use ruby", you really just mean "use erb in your config files" ?

Trying to disambiguate if you also mean "and then also something something something run ruby on the command line" (I don't think this is the case though)

[nickhammond]

Yes, just ERB.

[nickhammond]

Here's another post I just stumbled on https://www.reddit.com/r/rails/comments/1l8r97p/create_review_apps_from_your_pull_requests_with/