Files
shopdb-flask/shopdb/plugins/__init__.py
cproudlock 4d23f5b0fd Fix internal error when enabling a plugin
enable_plugin called register_blueprint at runtime, which Flask forbids after
the first request (AssertionError -> 500). Enabling now flips the registry flag
and fires on_enable best-effort; routes register on the next restart, symmetric
with disable. Nav reflects the re-enable immediately.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-26 16:05:18 -04:00

310 lines
10 KiB
Python

"""Plugin manager - main entry point for plugin system."""
from pathlib import Path
from typing import Dict, List, Optional
from flask import Flask
import logging
from .base import BasePlugin, PluginMeta
from .registry import PluginRegistry, PluginState
from .loader import PluginLoader
from .migrations import PluginMigrationManager
logger = logging.getLogger(__name__)
__all__ = [
'PluginManager',
'BasePlugin',
'PluginMeta',
'PluginRegistry',
'PluginState',
'plugin_manager'
]
class PluginManager:
"""
Central manager for all plugin operations.
Usage:
plugin_manager = PluginManager()
plugin_manager.init_app(app, db)
# In CLI:
plugin_manager.install_plugin('printers')
"""
def __init__(self):
self.registry: Optional[PluginRegistry] = None
self.loader: Optional[PluginLoader] = None
self.migration_manager: Optional[PluginMigrationManager] = None
self._app: Optional[Flask] = None
self._db = None
def init_app(self, app: Flask, db) -> None:
"""Initialize plugin manager with Flask app."""
self._app = app
self._db = db
# Setup paths
instance_path = Path(app.instance_path)
plugins_dir = Path(app.root_path).parent / 'plugins'
# Initialize components
self.registry = PluginRegistry(instance_path / 'plugins.json')
self.loader = PluginLoader(plugins_dir, self.registry)
self.migration_manager = PluginMigrationManager(
plugins_dir,
app.config.get('SQLALCHEMY_DATABASE_URI')
)
# Load enabled plugins
self._load_enabled_plugins()
# Store on app for access
app.extensions['plugin_manager'] = self
def _load_enabled_plugins(self) -> None:
"""Load and register all enabled plugins."""
plugins = self.loader.load_enabled_plugins(self._app, self._db)
for name, plugin in plugins.items():
self._register_plugin_components(plugin)
def upgrade_all_plugins(self) -> Dict[str, str]:
"""Run pending Alembic migrations for every loaded plugin.
Returns {plugin_name: 'ok'|'no-migrations'|<error str>}. Skips
plugins with no migrations/ directory. Use from the CLI
(`flask plugin upgrade-all`) on a fresh deploy after the core
schema is in place; existing deploys that still use db.create_all
can ignore this and continue to do so.
"""
results: Dict[str, str] = {}
if not self.migration_manager:
return results
plugin_names = list(self.registry.list_installed().keys()) \
if hasattr(self.registry, 'list_installed') else []
if not plugin_names:
# Fall back to whatever the loader found on disk.
plugin_names = self.loader.discover_plugins()
for name in plugin_names:
if not self.migration_manager.has_pending_migrations(name):
results[name] = 'no-migrations'
continue
try:
ok = self.migration_manager.run_plugin_migrations(name)
results[name] = 'ok' if ok else 'failed'
except Exception as ex:
results[name] = f'error: {ex}'
return results
def _register_plugin_components(self, plugin: BasePlugin) -> None:
"""Register plugin's blueprint, models, CLI commands, etc."""
# Register blueprint
blueprint = plugin.get_blueprint()
if blueprint:
self._app.register_blueprint(
blueprint,
url_prefix=plugin.meta.api_prefix
)
logger.debug(f"Registered blueprint: {plugin.meta.api_prefix}")
# Register CLI commands
for cmd in plugin.get_cli_commands():
self._app.cli.add_command(cmd)
def discover_available(self) -> List[Dict]:
"""
Get list of all available plugins (installed or not).
Returns list of plugin info dicts.
"""
available = []
for name in self.loader.discover_plugins():
plugin_class = self.loader.load_plugin_class(name)
if plugin_class:
try:
temp = plugin_class()
meta = temp.meta
state = self.registry.get(name)
available.append({
'name': meta.name,
'version': meta.version,
'description': meta.description,
'author': meta.author,
'dependencies': meta.dependencies,
'installed': state is not None,
'enabled': state.enabled if state else False,
'installedat': state.installed_at if state else None
})
except Exception as e:
logger.warning(f"Error inspecting plugin {name}: {e}")
return available
def install_plugin(self, name: str, run_migrations: bool = True) -> bool:
"""
Install a plugin.
Steps:
1. Verify plugin exists
2. Check dependencies
3. Run database migrations
4. Register in registry
5. Call plugin's on_install hook
"""
# Check if already installed
if self.registry.is_installed(name):
logger.warning(f"Plugin {name} is already installed")
return False
# Load plugin class
plugin_class = self.loader.load_plugin_class(name)
if not plugin_class:
logger.error(f"Plugin {name} not found")
return False
temp_plugin = plugin_class()
meta = temp_plugin.meta
# Check dependencies
for dep in meta.dependencies:
if not self.registry.is_installed(dep):
logger.error(
f"Plugin {name} requires {dep} to be installed first"
)
return False
# Run migrations
if run_migrations:
success = self.migration_manager.run_plugin_migrations(name)
if not success:
logger.error(f"Failed to run migrations for {name}")
return False
# Register plugin
self.registry.register(name, meta.version)
# Load the plugin
plugin = self.loader.load_plugin(name, self._app, self._db)
if plugin:
self._register_plugin_components(plugin)
plugin.on_install(self._app)
logger.info(f"Installed plugin: {name} v{meta.version}")
return True
def uninstall_plugin(self, name: str, remove_data: bool = False) -> bool:
"""
Uninstall a plugin.
Args:
name: Plugin name
remove_data: If True, run downgrade migrations to remove tables
"""
if not self.registry.is_installed(name):
logger.warning(f"Plugin {name} is not installed")
return False
# Check if other plugins depend on this one
for other_name in self.registry.get_enabled_plugins():
if other_name == name:
continue
other_plugin = self.loader.get_loaded_plugin(other_name)
if other_plugin and name in other_plugin.meta.dependencies:
logger.error(
f"Cannot uninstall {name}: {other_name} depends on it"
)
return False
# Get plugin instance
plugin = self.loader.get_loaded_plugin(name)
# Call on_uninstall hook
if plugin:
plugin.on_uninstall(self._app)
# Optionally remove data
if remove_data:
self.migration_manager.downgrade_plugin(name)
# Unregister
self.registry.unregister(name)
logger.info(f"Uninstalled plugin: {name}")
return True
def enable_plugin(self, name: str) -> bool:
"""Enable a disabled plugin."""
if not self.registry.is_installed(name):
logger.error(f"Plugin {name} is not installed")
return False
if self.registry.is_enabled(name):
logger.info(f"Plugin {name} is already enabled")
return True
# Check dependencies are enabled
plugin_class = self.loader.load_plugin_class(name)
if plugin_class:
temp = plugin_class()
for dep in temp.meta.dependencies:
if not self.registry.is_enabled(dep):
logger.error(f"Cannot enable {name}: {dep} is not enabled")
return False
self.registry.enable(name)
# Fire the on_enable hook best-effort. Do NOT register the blueprint
# here: Flask forbids register_blueprint after the first request, so
# routes/nav for a re-enabled plugin take effect on the next restart
# (symmetric with disable).
try:
plugin = self.loader.load_plugin(name, self._app, self._db)
if plugin:
plugin.on_enable(self._app)
except Exception:
logger.exception(f"on_enable hook failed for plugin {name}")
logger.info(f"Enabled plugin: {name}")
return True
def disable_plugin(self, name: str) -> bool:
"""Disable an enabled plugin."""
if not self.registry.is_enabled(name):
logger.info(f"Plugin {name} is already disabled")
return True
# Check if other plugins depend on this one
for other_name in self.registry.get_enabled_plugins():
if other_name == name:
continue
other_plugin = self.loader.get_loaded_plugin(other_name)
if other_plugin and name in other_plugin.meta.dependencies:
logger.error(
f"Cannot disable {name}: {other_name} depends on it"
)
return False
plugin = self.loader.get_loaded_plugin(name)
if plugin:
plugin.on_disable(self._app)
self.registry.disable(name)
logger.info(f"Disabled plugin: {name}")
return True
def get_plugin(self, name: str) -> Optional[BasePlugin]:
"""Get a loaded plugin instance."""
return self.loader.get_loaded_plugin(name)
def get_all_plugins(self) -> Dict[str, BasePlugin]:
"""Get all loaded plugins."""
return self.loader.get_all_loaded()
# Global plugin manager instance
plugin_manager = PluginManager()