Local Development

This tutorial will take you through the process of installing a development Rack on your local workstation and running your first App on it.


Before we begin you will need to install the convox CLI and a development Rack:

Verify installation

Verify that your development Rack is running with convox rack:

$ convox rack
Name     dev
Provider local
Router   router.dev.convox
Status   running
Version  3.0.0

Get an example applicaton

Clone the Rails example

$ git clone https://github.com/convox-examples/rails.git

Enter the directory with the example application

$ cd rails

Look at the convox.yml

$ cat convox.yml
    type: postgres
    build: .
    health: /health
    port: 3000
      - database

This convox.yml defines one Service named web. Each Process of this Service will listen on port 3000 and should respond with a successful response to a health check at GET /health.

This App also has one PostgreSQL Resource named database which is connected to the web Service. This will create a PostgreSQL database and make its connection information available to the web Processes as the environment variable DATABASE_URL.

Run the application locally

You can start an app against your development Rack using convox start:

The first time you run convox start on an application will take longer than usual because you won’t have anything cached.

$ convox start
build  | uploading source
build  | starting build
build  | Authenticating registry.dev.convox/rails: Login Succeeded
build  | Building: .
build  | Sending build context to Docker daemon  77.69MB
build  | Step 1/12 : FROM ruby:2.6.4 AS development
build  | 2.6.4: Pulling from library/ruby
build  | Digest: sha256:403a98dc3cc6737cc81ff5143acb50256ce46a65b462c8c75e1942a1c8480852
build  | Status: Downloaded newer image for ruby:2.6.4
build  |  ---> 121862ceb25f
build  | Step 2/12 : ENV RAILS_ENV development
build  |  ---> Running in 354878b13b32
build  | Removing intermediate container 354878b13b32
build  |  ---> 7359d7e18815
build  | Step 3/12 : RUN apt-get update && apt-get install -y nodejs npm postgresql-client
build  |  ---> Running in c8540dfe21b6
build  | Removing intermediate container c8540dfe21b6
build  |  ---> b3d0acfb372a
build  | Step 4/12 : RUN npm install -g yarn
build  |  ---> Running in 8bcd03f9c571
build  | added 1 package in 0.654s
build  | Removing intermediate container 8bcd03f9c571
build  |  ---> 9db86c97841f
build  | Step 5/12 : WORKDIR /usr/src/app
build  |  ---> Running in 00e392fb9ffb
build  | Removing intermediate container 00e392fb9ffb
build  |  ---> 0ef9e064dee2
build  | Step 6/12 : COPY Gemfile Gemfile.lock ./
build  |  ---> e61bf31b9497
build  | Step 7/12 : RUN bundle install
build  |  ---> Running in ef927a1ba0d7
build  | Bundle complete! 17 Gemfile dependencies, 75 gems now installed.
build  | Bundled gems are installed into `/usr/local/bundle`
build  | Removing intermediate container ef927a1ba0d7
build  |  ---> 9ef79cb583f9
build  | Step 8/12 : COPY package.json yarn.lock ./
build  |  ---> 5b2b243d810f
build  | Step 9/12 : RUN yarn install --check-files
build  |  ---> Running in 861e030377e0
build  | yarn install v1.22.0
build  | [1/4] Resolving packages...
build  | [2/4] Fetching packages...
build  | [3/4] Linking dependencies...
build  | [4/4] Building fresh packages...
build  | Done in 23.49s.
build  | Removing intermediate container 861e030377e0
build  |  ---> 63a446385c38
build  | Step 10/12 : COPY . .
build  |  ---> 11d5aa716a19
build  | Step 11/12 : EXPOSE 3000
build  |  ---> Running in 81e03ee67a6a
build  | Removing intermediate container 81e03ee67a6a
build  |  ---> 0153050d030c
build  | Step 12/12 : CMD ["rails", "server", "-b", "", "-p", "3000"]
build  |  ---> Running in b013715c9e03
build  | Removing intermediate container b013715c9e03
build  |  ---> b80559b89574
build  | Successfully built b80559b89574
build  | Successfully tagged e44305a1288f25f77d83bc4ef6ecf16c974c4b86:latest
build  | Running: docker tag e44305a1288f25f77d83bc4ef6ecf16c974c4b86 dev/rails:web.BLBXTCIKDBL
build  | Running: docker tag dev/rails:web.BLBXTCIKDBL registry.dev.convox/rails:web.BLBXTCIKDBL
build  | Running: docker push registry.dev.convox/rails:web.BLBXTCIKDBL
convox | starting sync from Gemfile to /usr/src/app/Gemfile.lock on web
convox | starting sync from . to /usr/src/app on web
convox | starting sync from package.json to /usr/src/app/yarn.lock on web
web    | Scaled up replica set web-85bcd457c4 to 1
web    | Created pod: web-85bcd457c4-m9mkq
web    | Successfully assigned dev-rails/web-85bcd457c4-m9mkq to docker-desktop
web    | => Booting Puma
web    | => Rails 6.0.0 application starting in development
web    | => Run `rails server --help` for more startup options
web    | Container image "registry.dev.convox/rails:web.BLBXTCIKDBL" already present on machine
web    | Created container main
web    | Started container main
web    | Puma starting in single mode...
web    | * Version 3.12.2 (ruby 2.6.4-p104), codename: Llamas in Pajamas
web    | * Min threads: 5, max threads: 5
web    | * Environment: development
web    | * Listening on tcp://
web    | Use Ctrl-C to stop
web    | Started GET "/health" for at 2020-02-11 15:24:11 +0000
web    | Cannot render console from! Allowed networks:, ::1

View the application in a browser

In another terminal navigate to the directory where you cloned the example app and run convox services:

$ convox services
SERVICE  DOMAIN                PORTS
web      web.rails.dev.convox  443:3000

Now in your browser navigate to https://web.rails.dev.convox

If you named your development Rack something other than dev this URL will be slightly different for you.

You should see logs in the first terminal that show your browser requesting the index page.

web    | Processing by Rails::WelcomeController#index as HTML
web    |   Rendering /usr/local/bundle/gems/railties-6.0.0/lib/rails/templates/rails/welcome/index.html.erb
web    |   Rendered /usr/local/bundle/gems/railties-6.0.0/lib/rails/templates/rails/welcome/index.html.erb (Duration: 3.8ms | Allocations: 194)
web    | Completed 200 OK in 8ms (Views: 4.4ms | ActiveRecord: 0.0ms | Allocations: 1053)

Make a change

Edit the file config/routes.rb and add the following line just before the final end:

get "/test", to: proc { [ 200, {}, ["Hello World!"] ] }

This will cause Rails to respond to GET /test requests with Hello World!.

You will see the change being synchronized up to your development Rack:

convox | sync: config/routes.rb to /usr/src/app on web

Now navigate to https://web.rails.dev.convox/test

You can make further changes to this route and it will be synchronized every time you save the file.

Run a command

You can use convox run to run one-off commands against the App:

$ convox run web rake db:migrate test
Finished in 5.053022s, 0.0000 runs/s, 0.0000 assertions/s.
0 runs, 0 assertions, 0 failures, 0 errors, 0 skips

Deploy the application

See the Deploying an Application guide to deploy this application to the internet.