PhoenixKit.ModuleDiscovery (phoenix_kit v1.7.164)

Zero-config auto-discovery of external PhoenixKit modules.

Uses the same pattern as Elixir's protocol consolidation: scans .beam files for persisted @phoenix_kit_module attributes via :beam_lib.chunks/2. No module loading required — pure file I/O.

How It Works

use PhoenixKit.Module persists @phoenix_kit_module true in the .beam file
This module scans only deps that depend on :phoenix_kit (fast, targeted)
Reads the persisted attribute from each beam file without loading the module
Works at both compile time (route generation) and runtime (ModuleRegistry)

Fallback

Also reads Application.get_env(:phoenix_kit, :modules, []) for backwards compatibility. Both sources are merged and deduplicated.

Summary

Functions

discover_external_modules()

Discovers external PhoenixKit modules from beam files + config fallback.

module_hash()

Returns a deterministic hash of the current set of discovered external modules.

phoenix_kit_dependent_apps()

Returns the names of dependency apps on disk that declare :phoenix_kit in their applications (i.e. via extra_applications).

scan_beam_files()

Scans beam files of phoenix_kit-dependent apps for @phoenix_kit_module attribute.

Functions

discover_external_modules()

@spec discover_external_modules() :: [module()]

Discovers external PhoenixKit modules from beam files + config fallback.

Returns a deduplicated list of module atoms that implement PhoenixKit.Module. Excludes internal modules (those in the PhoenixKit.Modules namespace that are bundled with PhoenixKit itself).

module_hash()

@spec module_hash() :: binary()

Returns a deterministic hash of the current set of discovered external modules.

Used by __mix_recompile__?/0 (injected into the host router) to detect when modules are added or removed, triggering router recompilation.

phoenix_kit_dependent_apps()

@spec phoenix_kit_dependent_apps() :: [atom()]

Returns the names of dependency apps on disk that declare :phoenix_kit in their applications (i.e. via extra_applications).

Filesystem-based, independent of load state. Used by the CSS-sources compiler to warn when discovery yields zero sources even though phoenix_kit-dependent deps are present.

scan_beam_files()

@spec scan_beam_files() :: [module()]

Scans beam files of phoenix_kit-dependent apps for @phoenix_kit_module attribute.

Walks dependency ebin directories on disk (pure file I/O) rather than relying on :application.loaded_applications/0, so it is deterministic at compile time — it returns the same set whether or not the apps happen to be loaded yet. An app qualifies when its <app>.app lists :phoenix_kit in applications; its beams are then read with :beam_lib.chunks/2 to keep the ones carrying @phoenix_kit_module true. No module loading required.