addon-system 1.2.3

The AddonSystem library

# Addon System

This is a fully rewritten RelativeAddonsSystem [PyPi] [GitHub]

What is it?

This is super useful (or useless. Depends on your mood) thing ever!

This is a library that allows you to manage "addons" in your project.

You want to install only one library? Just do it!

It has no third-party dependencies!

What is addon?

Beneficial thing!

Addon is a mini-project(usually independent) that provides an interface for your main project and can be used as a part of it.

Addon is a directory that contains at least two files:

• Addon metafile
• Addon main module

Addon metafile

Is a JSON formatted file. That consists of these values:

• id - string. Addons must have unique id. Usually consists of your username and addon name: KuyuGama/SomeAddon
• name - string. Name of addon. Can be used for frontend display
• module - string. Main module of addon
• authors - array[string]. Author names of addon
• version - [optional] string. Version of addon(usually SemVer)
• description - [optional]string. Description of addon. Can be used on frontend
• depends - [optional]array[string]. Addon dependencies. Format is library==version (such as pip). If you are using your own library managing class, you can change a string format to yours.
• extra - [optional]object. Addon extra info. Used to store custom values that can be changed in runtime.

Addon module

Is a standard python module! The only exception is an interface that will use your main code of project.

I've been inspired by a plugins for Minecraft servers cores such as a Paper to create this library!

What is addon for?

Speed or convenience? I choose both!

Addon is a runtime extension of your project. You can write update for your application and don't care about downtime (it will not be there!).

Or you can use addons just for creating extensible projects. For example, telegram bots, you can add some functionality with no need to edit the main code of the bot. Connect the addon!

Dependencies?

Where is aiogram gone?

This library has a built-in tool for managing addon's dependencies. So you don't even need to use command-line to install it using AddonSystem.

Let's try?

LET'S GOO!

Prerequisites

• Install addon-system

pip install addon-system

• Create addons storage directory, it can have any name and be anywhere inside your project workdir(of course!)

Example:

в”Њв”Ђ KuyuGenesis -- Workdir
в””в”Ђв”Ђв”Њв”Ђ addons -- here you go
   в”њв”Ђ src
   в”њв”Ђ main.py
   в”њв”Ђ config.py
   в””в”Ђ KuyuGenesis.conf

Create your first addon

There are two ways to achieve it

• Using library-provided addon creation command line tool:

python -m addon --name="SomeAddon" --authors="KuyuGama,Anon" --id="username/SomeAddon" --module="__init__.py" addons/ 

• Manually(meh) create addon dir and metafile:

в”Њв”Ђ SomeAddon -- AddonDir (CamelCase)
в””в”Ђв”Ђв”Њв”Ђ addon.json -- metafile
   в””в”Ђ __init__.py -- module set in metafile(can be any python file)

So you now have this project structure:

в”Њв”Ђ KuyuGenesis -- Workdir
в””в”Ђв”Ђв”Њв”Ђ addons 
   в”њв”Ђв”Ђв”Њв”Ђ SomeAddon -- Addon's directory
   в”‚  в””в”Ђв”Њв”Ђ addon.json -- metafile
   в”‚    в””в”Ђ __init__.py -- module set in metafile
   в”њв”Ђ src
   в”њв”Ђ main.py
   в”њв”Ђ config.py
   в””в”Ђ KuyuGenesis.conf

Initialize the system

from pathlib import Path

from addon_system import AddonSystem
from addon_system.libraries.pip_manager import PipLibManager

root = Path() / "addons"
system = AddonSystem(root, PipLibManager())

Here we created instance of the AddonSystem with early created addons root directory and pip library manager. If you use another library manging tool - write your own implementation of library manager that uses it (only three methods!).

Querying addons

Search of addons? YES!

For your needs, you can search for the addons(not on the internet! Yet?)

from pathlib import Path

from addon_system import AddonSystem
from addon_system.libraries.pip_manager import PipLibManager

root = Path() / "addons"
system = AddonSystem(root, PipLibManager())

for addon in system.query_addons(name="some", case_insensitivity=True):
    print(addon)

Here we queried for addon by its name case-insensitive. You can query addons by other fields also. Here are all query parameters:

• author — author name
• name — addon name
• description — description
• enabled — addon status(about this later)
• case_insensitivity — case-insensitive querying

Getting a specific addon

As I wrote above:

Addon's must have unique id

So, if you want to get some exact addon - use its id!

from pathlib import Path

from addon_system import AddonSystem
from addon_system.libraries.pip_manager import PipLibManager

root = Path() / "addons"
system = AddonSystem(root, PipLibManager())

addon = system.get_addon_by_id("KuyuGama/SomeAddon")
print(addon)

Addon details

What is the use of this addon?

You can get all supported values from metafile using AddonMeta that is always present in addon as "metadata" attribute:

from pathlib import Path

from addon_system import AddonSystem
from addon_system.libraries.pip_manager import PipLibManager

root = Path() / "addons"
system = AddonSystem(root, PipLibManager())

addon = system.get_addon_by_id("KuyuGama/SomeAddon")
metadata = addon.metadata
print(metadata.id)
print(metadata.name)
print(metadata.description)
print(metadata.version)
print(metadata.depends)
print(metadata.authors)
print(metadata.module)

Addon metafile has one more field "extra." Which can be used to store custom values:

from typing import Any
from pathlib import Path

from addon_system import AddonSystem, AddonMetaExtra
from addon_system.libraries.pip_manager import PipLibManager

root = Path() / "addons"
system = AddonSystem(root, PipLibManager())

addon = system.get_addon_by_id("KuyuGama/SomeAddon")


class Extra(AddonMetaExtra):
    __defaults__ = {"handles_events": []}
    handles_events: list[str]
    priority: int

    def validate(self, data: dict[str, Any]) -> bool:
        handles_events = data.get("handles_events")
        if not isinstance(handles_events, list):
            return False
        
        # If not all elements are str -> return False
        if isinstance(handles_events, list) and (
            len(handles_events) != 0
            and all(map(lambda e: isinstance(e, str), handles_events))
        ):
            return False

        return True


extra = addon.metadata.extra(Extra)

if "event" in extra.handles_events:
    print(f"{addon.metadata.id} can handle event \"event\"")
    # Set priority extra value and save metafile
    extra.priority = 0
    extra.save()

Note: you can read/edit addon extra info without the need to create your own AddonMetaExtra class subclass. But it is useful when you have to define types of field or validate data from extra info

Dependencies!

To manage dependencies, you have to use the simple interface:

from pathlib import Path

from addon_system import AddonSystem
from addon_system.libraries.pip_manager import PipLibManager

root = Path() / "addons"
system = AddonSystem(root, PipLibManager())

addon = system.get_addon_by_id("KuyuGama/SomeAddon")

print(addon.metadata.depends)
print("Is dependencies satisfied?", system.check_dependencies(addon))
if not system.check_dependencies(addon):
    system.satisfy_dependencies(addon)
    print("Auto-installed dependencies")
...

Here we checked dependencies of addon and installed it if necessarily

check_dependencies and satisfy_dependencies also can take addon id to manage

Thanks to caching we can call check_dependencies twice without losing much time

Addon status

Another useful (or useless, according to your purposes) think!

Addon status allows the code to know whether to load addon into your project

Usage:

from pathlib import Path

from addon_system import AddonSystem
from addon_system.libraries.pip_manager import PipLibManager

root = Path() / "addons"
system = AddonSystem(root, PipLibManager())

addon = system.get_addon_by_id("KuyuGama/SomeAddon")

if not system.get_addon_enabled(addon):
    system.enable_addon("KuyuGama/SomeAddon")
else:
    system.disable_addon("KuyuGama/SomeAddon")

for addon in system.query_addons(enabled=True):
    print("Enabled addon:", addon)

To remove confusion:

get_addon_enabled, enable_addon and disable_addon all can take id or instance of addon

Importing addon

Much more interesting, isn't it?

You can import or reload module of addon where and when you want:

from pathlib import Path

from addon_system import AddonSystem
from addon_system.libraries.pip_manager import PipLibManager

root = Path() / "addons"
system = AddonSystem(root, PipLibManager())

addon = system.get_addon_by_id("KuyuGama/SomeAddon")

module = addon.module()

# Example module interface
event_handlers = {}

module.unpack_handlers(event_handlers)

Note, addon can't be imported without satisfied dependencies. If dependencies are not satisfied, exception will be raised

Interface of addon module is your own designed interface for your purposes.

Because the module is a regular python module, you can
create whatever you want

Reload of module is achieved by using the same function with reload=True argument:

from pathlib import Path

from addon_system import AddonSystem
from addon_system.libraries.pip_manager import PipLibManager

root = Path() / "addons"
system = AddonSystem(root, PipLibManager())

addon = system.get_addon_by_id("KuyuGama/SomeAddon")

module = addon.module(reload=True)

Value injection

NOTE! That is not safe in case of usage threading! Because it replaces builtins (Only for import time)

Why builtins? Because it will work as it is (without any function calls in addon's module)

You can inject values on module initiation, and use it after (will work only for module that set into metafile)

Injection example:

from pathlib import Path

from addon_system import AddonSystem
from addon_system.libraries.pip_manager import PipLibManager

root = Path() / "addons"
system = AddonSystem(root, PipLibManager())

addon = system.get_addon_by_id("KuyuGama/SomeAddon")

# "this" name will contain addon instance in addon's module
module = addon.module(replace_names=dict(this=addon))

It creates problem - IDEs doesn't know that I injected the name "this".

Let's solve this!

from addon_system import resolve_runtime, Addon

this = resolve_runtime(Addon)

print("Addon module received \"this\" variable with value:", this)

Note:

1. resolve_runtime also checks requested type with a provided value type and will raise TypeError if it is different
2. resolve_runtime automatically resolves the name of required variable, but you can also pass it manually, by parameter name
3. resolve_runtime is a hack on builtins and it can be used in all child modules and will return the same value

Module Interface

Wait, what? My IDE now suggests to me methods that I could call!

How this works: you create class-representation of the module - library instantiates it with addon and allows you to use it anywhere.

Simple example:

from pathlib import Path
from typing import Any

from addon_system import AddonSystem, ModuleInterface
from addon_system.libraries.pip_manager import PipLibManager


class MyInterface(ModuleInterface):
    def get_supported_events(self) -> list[str]:
        """Returns supported events by this addon"""
        return self.get_func("get_supported_events")()

    def propagate_event(self, event_name: str, event_data: dict[str, Any]) -> bool:
        """Propagates event to this addon, and return True if handled"""
        handler = self.get_func("on_" + event_name)

        if handler is None:
            return False

        return handler(event_data)


root = Path() / "addons"
system = AddonSystem(root, PipLibManager())

addon = system.get_addon_by_id("KuyuGama/SomeAddon")

# Value injection can be achieved by using addon.module_names dictionary
addon.module_names.update(dict(this=addon))

interface = addon.interface(
    MyInterface,
    "supported on_load positional argument",
    kwd="supported on_load keyword argument",
)

if "smth" in interface.get_supported_events():
    interface.propagate_event("smth", dict(issued_by="User"))

ModuleInterface class has built-in methods to manipulate on addon's module:

get_func(name: str) — returns function with the given name, if it is not a function — returns None

get_attr(name: str[, default=Any]) — get attribute by the given name, if default is not set - raises AttributeError

set_attrs(**names) — set passed keyword arguments as module attributes

Module unloading

Free my memory, please

Library can try to unload addon's modules

Note: It works better in a pair of ModuleInterface

from pathlib import Path

from addon_system import AddonSystem, ModuleInterface
from addon_system.libraries.pip_manager import PipLibManager

root = Path() / "addons"
system = AddonSystem(root, PipLibManager())

addon = system.get_addon_by_id("KuyuGama/SomeAddon")

module = addon.module()

# To unload module => we must remove all references to it
# (and then python's garbage collector will release used memory by it)
del module
addon.unload_module()

# In case of usage ModuleInterface, it will try to unload 
# all used modules by this addon(addon's module must return 
# a list of the modules in on_load method)
interface = addon.interface(ModuleInterface)

# Will try to unload all used modules by its addon
interface.unload("Argument passed to on_unload module method")
## Or
# addon.unload_interface("Argument passed to on_unload module method")
## if you don't have access to interface instance

NOTE!!! Unload may not work in case if module is used anywhere else. If you use interface - use it instance instead of the addon's module

Also: to unload used modules by this addon => you need to return a list of these modules from on_load module method (it will be called automatically by ModuleInterface class)

I recommend not using addon's module object, instead use ModuleInterface. That is a good idea, because it will unload module if necessary

---

Addon interface

Independent addon? Huh

Addons are semi-independent components of AddonSystem.

This means you can use addons without AddonSystem(but with some limitations, of course)

Here are the all methods and properties of semi-independent component Addon:

1. Properties:
   • metadata — Metadata class contains all the metadata of addon
   • path — Path to addon
   • update_time — last update time of addon(retrieved from an operating system)
   • module_path — path to addon's module
   • module_names — names that will be passed to module on its import (can be modified)
   • module_import_path — path that passed into importlib.import_module to import module of addon
   • system — installed AddonSystem for this addon(not for independent usage)
   • enabled — addon status shortcut(not for independent usage)
2. Methods:

   • install_system(system: AddonSystem)

     • system — AddonSystem to install

     Install AddonSystem to this addon(usually used by AddonSystem)

   • module(lib_manager: BaseLibManager = None, reload: bool = False, replace_names: dict[str, Any] = None)

     • lib_manager — Library manager, used to check dependencies before import of module. You must pass it if you use addon as an independent object
     • reload — Pass True if you want to reload module(uses importlib.reload)
     • replace_names — values injection to module

     Import the Addon module

   • interface(cls: type[ModuleInterface], *args, **kwargs)

     • cls — subclass of ModuleInterface that will be instantiated
     • *args, **kwargs — will be passed to on_load method of the module

     Create ModuleInterface instance that can be used to access module variables with IDEs suggestions

   • unload_interface()

     • *args, **kwargs — will be passed to on_unload method of the addon

     Tries to unload module interface

   • unload_module()

     Tries to unload module

   • storage()

     Get the addon key-value storage. Use it if your addon has data to store

   • check_dependencies(lib_manager: BaseLibManager = None)

     • lib_manager — Library manager, used to check dependencies before import of module. You must pass it if you use addon as an independent object

     Check addon dependencies

   • satisfy_dependencies(lib_manager: BaseLibManager = None)

     • lib_manager — Library manage, used to install libraries. You must pass it if you use the addon as an independent component

     Install dependencies of this addon

   • set_enabled(enabled: bool)

     • enabled — status of addon

     Get the addon status (not for independent usage)

   • enable() Enable addon(not for independent usage)

   • disable() Disable addon(not for independent usage)

Thanks for using!