superfly / fly.cr

Crystal HTTP middleware to handle fly.io multi-region postgres replays.

fly.cr

Fly.io multi-region postgres support for crystal.

Installation

1. Add the dependency to your shard.yml:

   dependencies:
     fly:
       github: superfly/fly.cr
       version: ~> 0.1

2. Run shards install

Usage

Postgres via Avram

1. Add Multi-region postgres regional database readers and multi-region web application deployments via fly.io

2. Configure primary (writer) region by setting ENV $PRIMARY_REGION

3. Require fly/pg/error_handler and fly/avram after avram

   # src/shards.cr
   # ...
   require "avram"
   # ...
   require "fly/pg/error_handler"
   require "fly/avram"
   # ...

   This will add patching into avram in order to automatically change the port to read only port (5433) when the ENV["FLY_REGION"], set automatically by fly.io, based on your Fly configuration.

4. Add middleware to your HTTP stack. This supports any core Crystal HTTP server. The middleware must appear after any Error Handler middleware, such as the Lucky::ErrorHandler.

   For Lucky, this looks like this:

     def middleware : Array(HTTP::Handler)
       [
         # ...
         Lucky::ErrorHandler.new(action: Errors::Show),
         Raven::Lucky::ErrorHandler.new,
         Fly::PG::ErrorHandler.new,
         # ..,.
       ] of HTTP::Handler
     end

Configuration (Optional)

To override the use of ENV['PRIMARY_REGION'], you can set the Fly primary region by writing a fly config:

# config/fly.cr
Fly.configure do |settings|
   settings.primary_region = ENV["PRIMARY_REGION"] # Can be any string
end

Development

Deploy a Lucky app using the fly.io Run a Crystal App guide.

It's a bit of a pain because deploys take 3-5min, but it's the best development option as it provides integration testing.

Contributing

1. Fork it (https://github.com/superfly/fly-crystal/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• Alex Piechowski - creator and maintainer