PhoenixReverseProxy

Share a port between many Phoenix apps in an umbrella or multiple endpoints in a single app

Setup

This library offers all the essentials for directing requests and websockets from a single proxy application to your umbrella (or a standard Elixir app with various endpoints). It enables you to run multiple Phoenix applications within the same umbrella using the same port or have multiple endpoints within a single app.

Start by creating a Phoenix application in your umbrella apps folder:

(cd apps && mix phx.new --no-webpack --no-ecto --no-html --no-gettext --no-dashboard reverse_proxy)
# Optionally you can delete unused files
rm -rf apps/reverse_proxy/lib/reverse_proxy_web/{channels,controllers,views}

If available in Hex, the package can be installed by adding phoenix_reverse_proxy to your list of dependencies in mix.exs:

def deps do
  [
    {:phoenix_reverse_proxy, "~> 1.1.0"}
  ]
end

In apps/reverse_proxy/lib/reverse_proxy_web/endpoint.ex replace the contents with this and replace the default endpoint and add appropriate endpoints:

defmodule ReverseProxyWeb.Endpoint do
  use PhoenixReverseProxy, otp_app: :reverse_proxy

  # IMPORTANT: All of these macros except for proxy_default/1
  #            can take a path prefix so they all have an arity
  #            of 2 and 3.

  # Maps to http(s)://api.example.com/v1
  proxy("api.example.com", "v1", ExampleApiV1.Endpoint)

  # Maps to http(s)://api.example.com/v2
  proxy("api.example.com", "v2", ExampleApiV2.Endpoint)

  # Matches the domain only and no subdomains
  proxy("example.com", ExampleWeb.Endpoint)
  # Matched any subdomain such as http(s)://images.example.com/
  # but not the domain itself http(s)://example.com/
  proxy_subdomains("example.com", ExampleSubs.Endpoint)

  # Matches all subdomains and the domain itself.
  # This is equivalent to combining these rules:
  #   proxy("foofoovalve.com", FoofooValve.Endpoint)
  #   proxy_subdomains("foofoovalve.com", FoofooValve.Endpoint)
  proxy_all("foofoovalve.com", FoofooValve.Endpoint)

  # Matches anything not matched above
  proxy_default(ExampleWeb.Endpoint)
end

In your config you must disable your other Phoenix applications from listening on TCP ports. In your current endpoint configuration make the following modifications.

# Configures the endpoint
config :example_web, ExampleWeb.Endpoint,
  # Add this
  server: false,
  # Remove this and add it to the proxy endpoint configuration
  http: [port: System.get_env("PHX_PORT") || 4000],
  ...

Move contents of the files apps/reverse_proxy/config/*.exs to the corresponding config/*.exs config files.

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/phoenix_reverse_proxy.