Orion

Official Documentation on Hexdoc

Orion is a Dynamic Distributed Profiler. It allows you to profile any function in a beam cluster and get back an histogram representing the profile of the function calls across the whole cluster. Live, with low overhead, making it suitable to run in production. It uses Erlang dynamic tracing under the hood.

It is meant to be used as a library in part of your existing application.

If you run your application non clustered, you will be able to trace the node you connect to.

If your applications are connected via Distributed Erlang, then you will get a histogram of every call on every node, aggregated.

Non Goals

• Be useable in any BEAM language. This may happen in the future but for now we depend on dog_sketch which is in elixir
• Making it easy to run the UI locally and connect remotely to a cluster. This may come in the future or in a paid extension. If you are interested, contact me on the Elixir Forum. In the meantime, you can use the mix dev local development setup as a starting point to do your own. Orion totally work remotely connected with erlang distribution, so as long as you can connect to your cluster (and deactivate the :self_profile option in your endpont), it should just work.
• Session handling, in particular personal auth, and more. This may come in the future or in a paid extension. If you are interested, contact me on the Elixir Forum. Refreshes clean up the UI.

Installation

To start using Orion, you will need three steps:

1. Add the orion dependency
2. Configure LiveView
3. Add UI access

1. Add the orion dependency

Add the following to your mix.exs and run mix deps.get:

def deps do
  [
    {:orion, "~> 1.0"}
  ]
end

2. Configure LiveView

The Orion UI is built on top of LiveView. If LiveView is already installed in your app, feel free to skip this section.

If you plan to use LiveView in your application in the future, we recommend you to follow the official installation instructions. This guide only covers the minimum steps necessary for the Orion UI itself to run.

First, update your endpoint's configuration to include a signing salt. You can generate a signing salt by running mix phx.gen.secret 32 (note Phoenix v1.5+ apps already have this configuration):

# config/config.exs
config :my_app, MyAppWeb.Endpoint,
  live_view: [signing_salt: "SECRET_SALT"]

Then add the Phoenix.LiveView.Socket declaration to your endpoint:

socket "/live", Phoenix.LiveView.Socket

And you are good to go!

3. Add Orion UI access for development-only usage

Once installed, update your router's configuration to forward requests to an OrionWeb with a unique name of your choosing:

# lib/my_app_web/router.ex
use MyAppWeb, :router
import OrionWeb.Router
...
if Mix.env() == :dev do
  scope "/" do
    pipe_through [:browser]
    live_orion "/orion"
  end
end

This is all. Run mix phx.server and access the "/orion" to start profiling.

Extra: Add Orion access on all environments (including production)

If you want to use the Orion UI in production, you should put it behind some authentication and allow only admins to access it.

If you have an authentication layer already for admins, live_orion accept an :on_mount option, to specify the hooks to validate your authentication, as described in the official phoenix guide about security

If your application does not have an admins-only section yet, you can use Plug.BasicAuth to set up some basic authentication as long as you are also using SSL (which you should anyway):

# lib/my_app_web/router.ex
use MyAppWeb, :router
import OrionWeb.Router
...
pipeline :admins_only do
  plug :admin_basic_auth
end
scope "/" do
  pipe_through [:browser, :admins_only]
    live_orion "/orion"
end
defp admin_basic_auth(conn, _opts) do
  username = System.fetch_env!("AUTH_USERNAME")
  password = System.fetch_env!("AUTH_PASSWORD")
  Plug.BasicAuth.basic_auth(conn, username: username, password: password)
end

If you are running your application behind a proxy or a webserver, you also have to make sure they are configured for allowing WebSocket upgrades. For example, here is an article on how to configure Nginx with Phoenix and WebSockets.

Finally, you will also want to configure your config/prod.exs and use your domain name under the check_origin configuration:

    check_origin: ["//myapp.com"]

Then you should be good to go!

Contributing

You need elixir 1.12+ and OTP 24+.

Orion is a phoenix liveview application for the frontend.

To start your Phoenix server:

• Install dependencies with mix setup

If you want to see it in action

• Start the development endpoint with mix dev

Now you can visit localhost:4001 from your browser.

License

MIT License. Copyright (c) 2023 Thomas Depierre.