[Feature] Implement Settings Management via `settings.py`

[davidebizzocchi]

Problem Description

1. Inflexible Class Configuration
   Currently, it's impossible to configure core classes (e.g., CheshireCat/StrayCat) with custom implementations.

2. .env Limitations
   Complex or dynamic configurations can't be properly handled through .env files alone.

Proposed Solution

Overview

Use a settings.py file(s) to configure a setting object (alà django).
Then reference this object to retrieve variables when needed.

'settings.py' Structure:

1. Core
   • Location: cat/settings/settings.py
   • Purpose: mountable in Docker (like plugins)
2. In Plugins
   • Location: settings.py in plugin folder
   • Purpose: Manage plugin and Cat configurations

Implementation Details

1. Folder Structure

• Create cat/settings/ directory containing:
  • settings.py - User-configurable file (mountable in Docker)
  • default.py - Contains default configurations

2. Settings Object

• Load defaults in startup.py's lifespan function
• Ensure type safety: Default values enforce type checking for user-provided values
  (Example: If default is a class, users can't set a list)

3. Variable Access Methods

Two proposed approaches:

First Solution
Direct access via settings object:

app.state.ccat = cat_settings.get(CheshireCat)(cheshire_cat_api)
# or
app.state.ccat = cat_settings.CheshireCat(cheshire_cat_api)

Second Solution
Special setting-aware classes:

app.state.ccat = CheshireCatSetting(cheshire_cat_api)
# or
app.state.ccat = CheshireCat(cheshire_cat_api)  # Imported from settings-aware module

Comparison Table

Solution	Pros	Cons
First	- Simpler implementation	- Requires codebase-wide updates for new variables - Potentially harder to maintain
Second	- Cleaner implementation - Minimal codebase changes needed - Folder structure	- Slightly more complex initial setup - Folder structure

Personal recommendation: The second solution is preferable as it avoids cluttering the code with explicit settings calls.

Plugin Challenges

1. Settings File Conflict

   • settings.py is already used for plugin initialization
   • Solution: Allow coexistence by filtering variables (e.g., ignore _prefix names)

2. Loading Timing

   • Option A: Load with defaults in startup.py
     • Pros: Consistent initialization
     • Cons: Requires duplicate plugin validation logic
   • Option B: Load during plugin.activate()
     • Pros: Proper plugin state validation
     • Cons: Can't override pre-instantiated classes (e.g., CheshireCat)
   • I vote for Option B

3. Deactivation Handling

   • Deactivated plugins require full restart to reset settings (not mandatory to implement)
     NOTE: plugin toggling is rare during normal Cat usage.
   • Solution: Add admin panel restart button for convenience

Additional Context

Initial implementation available here:
https://github.com/davidebizzocchi/cheschire-cat-core/tree/setting-file

Other references on this topic

• [Huge Feature] Deprecate metadata.json in favour of SQL #994 (comment)
• Enhance Caching System and Optimize Memory Usage with Customizable Storage Support #1016 (comment)

[pieroit]

Hi @davidebizzocchi thanks
Let's keep this in standby for V2