Programming Phoenix 1.4

Introspecting Applications with Observer

Every time we start our Rumbl application, we have multiple applications running side by side. Each of our dependencies is in fact its own application. Phoenix and Elixir itself are applications too! An Application in Elixir is a runtime concern with these responsibilities:

• Applications package our code. Every time we compile our rumbl project, Mix prints “Generated rumbl app”. Open the file _build/dev/lib/rumbl/ebin/rumbl.app. It mostly contains metadata about the application, such as its modules, processes, a description and more.

• Supervisors can start and stop applications as a unit. An application may have a supervision tree, which defines exactly which services to start when the application starts, ...