A plugin for puma that'll start a ngrok tunnel to your rails server when puma starts. Primary I built this to make the following a easier:

This gem is not longer actively maintained, I suggest using theses alternatives instead:

• Overmind or Foreman
• Docker ngrok

• Working with apps that require Webhooks to be received by the app to work correctly
• Demoing your local rails app to someone else
• Working with Puma-dev so your apps feels as production-like as possible
• Testing on mobile.

I've setup a sample Rails 6 app which demos an implementation of this gem.

Make sure you have installed ngrok on your machine:

$ brew tap caskroom/cask
$ brew cask install ngrok

I've automated these steps into an app:template which can be found on Rails Bytes. However, if you'd like to install it manually follow these steps:

1. Add this line to your application's Gemfile:

group :development do
  gem 'puma-ngrok-tunnel'
end

2. And then execute:

$ bundle

3. Append this line to your config/puma.rb file:

plugin :ngrok_tunnel if ENV.fetch('RAILS_ENV') { 'development' } == 'development'

4. Lastly, update your config/environments/development.rb to include the line:

# puma-ngrok-tunnel: Allow connections from ngrok
config.hosts << /[a-z0-9.]+.ngrok.io/

Read about how to configure puma to use this in the Puma documentation.

There are a few variables this plugin reads from the environment which control its behavior. These are based on the arguments you'd pass to the ngrok terminal command.

• PORT - Optional, your rails port, defaults to 3000. If NGROK_ADDR is set, this is ignored.
• NGROK_ADDR - Optional, if you're using Puma-dev set this to be your hostname & port, e.g. my-app-name.test:443.
• NGROK_AUTHTOKEN - Optional, your ngrok authtoken. If you have ngrok configured on your local machine you don't need this.
• NGROK_HOST_HEADER - Optional, if you're using Puma-dev you should set this to your virtual host e.g. my-app-name.test.
• NGROK_CONFIG - Optional, your ngrok configuration file location, defaults to ~/.ngrok2/ngrok.yml.
• NGROK_SUBDOMAIN - Optional, ngrok will assign you a random subdomain unless this is set.
• NGROK_REGION - Optional, the region of your ngrok tunnel. The default is us.
• NGROK_HOSTNAME - Optional, full ngrok hostname, shouldn't be set if NGROK_SUBDOMAIN is set.

# puma-ngrok-tunnel setup
# You need https://github.com/bkeepers/dotenv setup to make sure Puma can use these.
export NGROK_TUNNEL_ENABLED=true
export NGROK_SUBDOMAIN=my-app-name
export NGROK_REGION=eu

# Puma-dev: You need to define this otherwise it uses it's own puma.rb file.
CONFIG=config/puma.rb

# puma-ngrok-tunnel setup
# These should start with 'export' otherwise puma-dev won't use them.
export NGROK_SUBDOMAIN=my-app-name
export NGROK_REGION=eu
# The URL (and HTTPS Port) you might use to access this under Puma-dev
export NGROK_ADDR=my-app-name.test:443
export NGROK_HOST_HEADER=my-app-name.test

If you see an error saying http: proxy error: dial unix, it means ngrok was able to stop when puma was stopped. Right now the solution is to run:

pkill ngrok

in your terminal.

If you seeing an error like:

Blocked host: a620ba29.ngrok.io

To allow requests to a620ba29.ngrok.io, add the following to your environment configuration:

config.hosts << "a620ba29.ngrok.io"

Open your config/environments/development.rb file add add:

# Safelist ngrok connections to development environment.
config.hosts << /[a-z0-9]+\.ngrok\.io/
# Safelist Puma-Dev hostname.
config.hosts << 'samplerailsapp.test'
config.hosts << /[a-z0-9]+\.samplerailsapp.test/

This will safe-list the ngrok subdomain to access your rails host.

The gem is available as open source under the terms of the MIT License.