"""Plugin manager - main entry point for plugin system.""" from pathlib import Path from typing import Dict, List, Optional from flask import Flask import logging import re from .base import BasePlugin, PluginMeta, renderable_settings_routes from .registry import PluginRegistry, PluginState from .loader import PluginLoader from .migrations import PluginMigrationManager from ..exceptions import PluginError 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 # Plugins installed while the app was already serving, whose blueprint # and CLI registration had to wait for a restart. The loader counts them # as loaded (it instantiated them), so this is the only record that # their ROUTES are not live yet. self._deferred_registration: set = set() # Plugins whose routes this process registered at startup. See # _load_enabled_plugins. self._booted_with: set = set() self.migration_manager: Optional[PluginMigrationManager] = None self.verifier = None self._app: Optional[Flask] = None self._db = None # API prefixes already claimed by a registered plugin blueprint, to # detect two plugins overlapping on the same /api/... namespace. self._registered_prefixes: set = set() def init_app(self, app: Flask, db) -> None: """Initialize plugin manager with Flask app.""" self._app = app self._db = db # Reset per-app so the prefix-uniqueness guard tracks only this app's # registrations (the manager is a process-wide singleton; tests build # multiple apps from it). self._registered_prefixes = set() # 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') ) # One trust policy, shared by verify-at-load and verify-at-migrate. from .verification import PluginVerifier verifier = PluginVerifier( plugins_dir, require_signed=app.config.get('PLUGIN_REQUIRE_SIGNED', False), trusted_key_paths=app.config.get('PLUGIN_TRUSTED_KEYS', []), dev_trust_dirs=app.config.get('PLUGIN_DEV_TRUST_DIRS', []), is_dev=bool(app.config.get('DEBUG') or app.config.get('TESTING')), ) self.verifier = verifier self.loader.verifier = verifier self.migration_manager.verifier = verifier # Install (or clear) the import guard that verifies every `plugins.*` # import against a trusted signature. This is what covers the core # request handlers that do `from plugins..models import ...`, which # never pass through the loader (findings #1, #2). from . import importguard if verifier.require_signed: importguard.install(plugins_dir, verifier) else: importguard.uninstall() # 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) # What THIS process actually registered routes for, recorded at boot. # Everything else is per-process and cannot answer "does the fleet need # a restart": under gunicorn each worker has its own manager, its own # loader and its own copy of the registry, so a plugin enabled through # one worker is invisible to the other three. Comparing this snapshot # against plugins.json re-read from disk is correct in every worker, # because a plugin enabled after boot is absent from every worker's # snapshot no matter which one served the enable. self._booted_with = set(plugins.keys()) for name, plugin in plugins.items(): self._register_plugin_components(plugin) self._check_settings_routes(name, plugin) def _check_settings_routes(self, name: str, plugin: BasePlugin) -> None: """Say at boot, once per plugin, if a declared settings tab is dead. Only some settings hubs draw plugin tabs (see SETTINGS_HUBS_WITH_PLUGIN_TABS). A route for any other hub is accepted by the hook and returned by the API and then rendered by nobody, which looks from every side like the plugin is at fault. The API drops such a route; this makes the same finding at startup, so it is in the log of a site that never opens the settings page.""" try: renderable_settings_routes(name, plugin.get_settings_routes(), logger) except Exception: logger.exception("get_settings_routes failed for %s", name) def upgrade_all_plugins(self) -> Dict[str, str]: """Run pending Alembic migrations for every discovered plugin. Returns {plugin_name: 'ok'|'no-migrations'|}. Skips plugins with no migrations/ directory. Driven by the CLI (`flask plugin upgrade-all`), which every deploy runs after `flask db upgrade`. Each bundled plugin's chain begins with a stamp-only anchor (the core chain already built its tables); later per-plugin migrations extend that chain. See ADR-008. Idempotent. """ results: Dict[str, str] = {} # Settings declared by a later plugin version reach an already-installed # site here. on_install/on_enable fire only on a state transition, so an # upgrade is the only moment left to seed them. Runs even with no # migration manager - it is independent of the Alembic chains. self.sync_all_plugin_settings() # Permissions need the same treatment for the same reason. A permission # added in a later plugin version would otherwise exist only after a # manual `flask seed permissions`, and until someone ran it the route # guarding on that name would refuse every caller - including admins on # sites that gate by permission rather than role. Deploys run # upgrade-all, so this is the moment the new name has to appear. self.sync_all_plugin_permissions() if not self.migration_manager: return results # Only ADOPTED plugins (those in the registry) get migrated. A plugin # folder that merely sits on disk unadopted must not have its DDL run as # a side effect of a deploy - migrations execute with full DB rights, so # "on disk" is not "trusted to run". (The old code probed a # list_installed() method the registry never had, so it always fell # through to discover_plugins() and migrated every folder.) plugin_names = list(self.registry.get_all().keys()) for name in plugin_names: if not self.migration_manager.has_pending_migrations(name): results[name] = 'no-migrations' continue try: self._release_session_locks() 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 sync_all_plugin_settings(self) -> int: """Seed every enabled plugin's declared settings. Idempotent. Returns the number of plugins whose settings were touched. Best-effort per plugin: one bad plugin must not abort a deploy's upgrade pass. """ touched = 0 for name in list(self.registry.get_all().keys()): if not self.registry.is_enabled(name): continue try: plugin = self.loader.load_plugin(name, self._app, self._db) except Exception: logger.exception("Could not load %s to sync its settings", name) continue if plugin and self._seed_plugin_settings(plugin): touched += 1 return touched def sync_all_plugin_permissions(self) -> int: """Seed every enabled plugin's declared permissions, then relink scopes. Returns the number of plugins whose permissions were seeded. Best-effort per plugin: one bad plugin must not abort a deploy's upgrade pass. The scope relink is the load-bearing half. Creating the Permission row only makes the name exist; the prebuilt scopes derive their grants from the catalog, so a permission seeded without a following Role.seedscopes() belongs to nobody but admin. The symptom is a plugin that installs cleanly and whose UI is invisible to every non-admin until someone re-runs the seed by hand. Ordering matters for the same reason it does in `flask seed permissions`: seedscopes only links rows that already exist, so it runs last. """ touched = 0 for name in list(self.registry.get_all().keys()): if not self.registry.is_enabled(name): continue try: plugin = self.loader.load_plugin(name, self._app, self._db) except Exception: logger.exception( "Could not load %s to sync its permissions", name) continue if plugin: self._seed_plugin_permissions(plugin) touched += 1 # Additive: this can hand a scope a newly declared permission, never # take one away, so a site's deliberate role edits survive the deploy. from shopdb.core.models import Role try: with self._app.app_context(): result = Role.seedscopes() self._db.session.commit() granted = sum((result or {}).get('granted', {}).values()) if granted: logger.info( "Linked %d new scope grant(s) after plugin upgrade", granted) except Exception: logger.exception("Could not relink prebuilt scopes after upgrade") return touched def get_declared_plugin_settings(self) -> Dict[str, dict]: """Return {key: declared entry} across all loaded plugins. The settings API uses this to file a first-time write under the owning plugin's category instead of a placeholder, and to decide which keys an unauthenticated caller may read. """ declared: Dict[str, dict] = {} for name, plugin in self.loader.get_all_loaded().items(): try: entries = plugin.get_settings_defaults() or [] except Exception: logger.exception("get_settings_defaults failed for %s", name) continue for entry in entries: key = entry.get('key') if key: declared[key] = entry return declared def get_public_setting_keys(self) -> set: """Setting keys plugins declare readable without authentication.""" return {key for key, entry in self.get_declared_plugin_settings().items() if entry.get('public')} def _release_session_locks(self) -> None: """Close this request's transaction before any plugin DDL runs. SELF-DEADLOCK, AND WHY IT TAKES THE WHOLE SITE DOWN. Enabling a plugin over HTTP arrives inside a request that has already authenticated, and @jwt_required does a SELECT on users - so the request's session is sitting in an open transaction holding a SHARED_READ metadata lock on users. The plugin's migrations then run through Alembic, which builds its OWN connection; a plugin table with a foreign key to users ( endpointlocks, policyactionholds, endpointlogcollections and others) needs an EXCLUSIVE metadata lock on it. That second connection waits on the first, the first cannot commit because the request is blocked on the second, and it never resolves. It does not stop at the one request. MySQL grants metadata locks in request order, so every later SELECT on users queues BEHIND the pending exclusive even though those reads are compatible with the shared lock already held. Every login on the site then hangs: observed as a total outage from one plugin toggle. Committing first ends the transaction and drops the lock, so the DDL takes its exclusive lock immediately. The session stays usable - the next statement simply begins a new transaction. """ if self._db is None: return try: self._db.session.commit() except Exception: try: self._db.session.rollback() except Exception: pass def _register_plugin_components(self, plugin: BasePlugin) -> None: """Register plugin's blueprint, models, CLI commands, etc. NOT POSSIBLE ON A LIVE APP, and that is fine. Flask refuses register_blueprint once the app has served its first request, raising AssertionError. Installing a plugin at runtime - which is exactly what enabling one from the setup wizard or the plugins page does - therefore used to run the plugin's migrations, update the registry, and THEN blow up with a 500, leaving the operator with an error over a change that had in fact been recorded. Routes only ever take effect on restart anyway; the UI has always said so. So on a live app, skip the parts that mutate app setup and let the restart register them properly. The registry entry, the migrations, the permissions and the settings - everything that belongs in the database - still happen here. """ # Flask renamed this: 2.x exposed `got_first_request` publicly, 3.x # keeps it as `_got_first_request`. Check both, because defaulting to # False on the wrong name silently disables this guard - which is how # the 500 survived the first attempt at this fix. served = getattr(self._app, 'got_first_request', None) if served is None: served = getattr(self._app, '_got_first_request', False) if served: self._deferred_registration.add(plugin.meta.name) logger.info( "%s installed while the app is serving; its blueprint and CLI " "commands register on the next restart (Flask does not allow " "either after the first request).", plugin.meta.name) return # Register blueprint blueprint = plugin.get_blueprint() if blueprint: prefix = plugin.meta.api_prefix # Guard against two plugins claiming the same API prefix; Flask only # rejects duplicate blueprint names, not overlapping url_prefixes, so # an overlap would silently shadow routes. if prefix in self._registered_prefixes: raise ValueError( f"Plugin {plugin.meta.name} api_prefix '{prefix}' is already " f"claimed by another blueprint" ) self._app.register_blueprint(blueprint, url_prefix=prefix) self._registered_prefixes.add(prefix) logger.debug(f"Registered blueprint: {prefix}") # Register CLI commands for cmd in plugin.get_cli_commands(): self._app.cli.add_command(cmd) def get_booted_with(self) -> set: """Plugins this process registered routes for at startup.""" return set(self._booted_with) def enabled_on_disk(self) -> set: """Enabled plugins per plugins.json, re-read now. The in-memory registry is per-worker and goes stale the moment another worker enables something, so a restart check must go back to the file. """ import json try: path = self.registry.state_file with open(path) as handle: data = json.load(handle) return {name for name, state in (data.get('plugins') or {}).items() if state.get('enabled')} except FileNotFoundError: return set() except Exception: # Unreadable or corrupt: fall back to this worker's view rather # than claiming nothing is enabled. return set(self.registry.get_enabled_plugins()) def get_deferred_registrations(self) -> set: """Plugins enabled in this process whose routes await a restart. get_all_loaded() is not a substitute: install_plugin instantiates the plugin through the loader, so a plugin whose blueprint was skipped still reports as loaded. Without this, a health check says no restart is needed while every one of that plugin's routes answers 404. """ return set(self._deferred_registration) 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(): # Under enforcement load_plugin_class refuses an unverified plugin # (it will not import it). Skip such a plugin from the listing # instead of failing the whole call. try: plugin_class = self.loader.load_plugin_class(name) except PluginError as e: logger.warning(f"Skipping plugin {name} in listing: {e}") continue if plugin_class: try: temp = plugin_class() meta = temp.meta state = self.registry.get(name) try: config_schema = temp.get_config_schema() except Exception: config_schema = [] try: provisioning_note = temp.get_provisioning_note() except Exception: provisioning_note = None manifest = self.loader.load_manifest(name) available.append({ 'name': meta.name, # Human label for UIs. Manifest display_name wins; else # title-case the machine name (right for most, e.g. # "computers" -> "Computers"). 'displayname': (manifest.get('display_name') or meta.name.replace('_', ' ').title()), '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, 'config_schema': config_schema, 'provisioning_note': provisioning_note, 'default_enabled': manifest.get('default_enabled', True), # Declared per plugin in its manifest, not held as a # list in the wizard, so adding a plugin cannot leave # the recommendation out of date in another file. 'recommended': bool(manifest.get('recommended', False)), }) 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 # Read metadata from the manifest (single source of truth) instead of # instantiating the plugin class just to inspect deps/version. manifest = self.loader.load_manifest(name) if not manifest: logger.error(f"Plugin {name} not found") return False manifest_version = manifest.get('version') # Check dependencies for dep in manifest.get('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: self._release_session_locks() success = self.migration_manager.run_plugin_migrations(name) if not success: logger.error(f"Failed to run migrations for {name}") return False # Register plugin # Plugins that provision extra tables install disabled until a site # opts in (manifest default_enabled=false). self.registry.register(name, manifest_version, enabled=manifest.get('default_enabled', True)) # Load the plugin plugin = self.loader.load_plugin(name, self._app, self._db) if plugin: self._register_plugin_components(plugin) self._seed_plugin_permissions(plugin) self._seed_plugin_settings(plugin) plugin.on_install(self._app) logger.info(f"Installed plugin: {name} v{manifest_version}") return True def _seed_plugin_permissions(self, plugin: BasePlugin) -> None: """Idempotently create Permission rows for a plugin's declared perms. Runs at install and enable so a fresh plugin's RBAC permissions exist without a separate `flask seed permissions` pass. Best-effort: a plugin that raises must not abort the lifecycle.""" try: entries = plugin.get_permissions() or [] except Exception: logger.exception( "get_permissions failed for %s", plugin.meta.name) return if not entries: return from shopdb.core.models import Permission with self._app.app_context(): created = Permission.seed_entries(entries) if created: self._db.session.commit() logger.info( "Seeded %d permission(s) for plugin %s", created, plugin.meta.name) def _seed_plugin_settings(self, plugin: BasePlugin) -> bool: """Idempotently create Setting rows for a plugin's declared settings. Runs at install, at enable, and on `flask plugin upgrade-all`. Existing values are never overwritten - only missing rows are created, and a row whose category does not match the declaration is re-homed. That repair matters: before a key was declared, the first save created it under the settings API's placeholder category, where the owning plugin's settings page (which filters by category) could not see it again, so the value looked like it never saved. Returns True if anything was created or repaired. Best-effort: a plugin that raises must not abort the lifecycle. """ try: entries = plugin.get_settings_defaults() or [] except Exception: logger.exception( "get_settings_defaults failed for %s", plugin.meta.name) return False if not entries: return False from shopdb.core.models import Setting created = 0 repaired = 0 with self._app.app_context(): for entry in entries: key = entry.get('key') if not key: continue setting = Setting.query.filter_by(key=key).first() if setting is None: self._db.session.add(Setting( key=key, value=entry.get('value', ''), valuetype=entry.get('valuetype', 'string'), category=entry.get('category', 'plugin'), description=entry.get('description'), )) created += 1 continue category = entry.get('category') if category and setting.category != category: setting.category = category repaired += 1 if created or repaired: self._db.session.commit() logger.info( "Plugin %s settings: %d created, %d re-homed", plugin.meta.name, created, repaired) return bool(created or repaired) def _is_core_tier(self, name: str) -> bool: """True when the plugin's manifest marks it tier=core (mandatory). A core-tier plugin refuses uninstall/disable so a site cannot remove a plugin its deployment depends on. No plugin ships tier=core today; the guard makes that a manifest edit, not a code change (ADR-013). """ try: return self.loader.load_manifest(name).get('tier') == 'core' except PluginError: return False def _installed_dependents(self, name: str, enabled_only: bool = False) -> List[str]: """Installed plugins that declare `name` as a hard dependency. Reads each dependency list from the manifest on DISK, not from a loaded plugin instance, so a dependent that is installed-but-not-loaded (e.g. disabled, or failed to load) is still counted. enabled_only restricts to currently-enabled dependents (what matters when disabling, since a disabled dependent is not running). """ dependents = [] for other_name, state in self.registry.get_all().items(): if other_name == name: continue if enabled_only and not state.enabled: continue try: manifest = self.loader.load_manifest(other_name) except PluginError: continue if name in manifest.get('dependencies', []): dependents.append(other_name) return dependents 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 if self._is_core_tier(name): logger.error(f"Cannot uninstall {name}: it is a core-tier plugin") return False # Refuse if any INSTALLED plugin (enabled or not) depends on this one. dependents = self._installed_dependents(name) if dependents: logger.error( f"Cannot uninstall {name}: {', '.join(dependents)} depend(s) 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. Auto-installs if available but not installed.""" # Security: Validate plugin name to prevent path traversal # Only allow alphanumeric, underscore, and hyphen (matches existing plugins) if not re.match(r'^[a-zA-Z0-9_-]+$', name): logger.error(f"Invalid plugin name format: {name}") return False # Reject reserved names that could be used for directory traversal if name in ('.', '..', ''): logger.error(f"Invalid plugin name: {name}") return False # Decisions below read the registry, so start from what is on disk # rather than this worker's boot snapshot. self.registry.refresh() # Auto-install if available but not installed (UX: enabling should just work) if not self.registry.is_installed(name): logger.info(f"Plugin {name} not installed, installing first") if not self.install_plugin(name): logger.error(f"Failed to install plugin {name}") return False if self.registry.is_enabled(name): logger.info(f"Plugin {name} is already enabled") return True # Check dependencies are enabled. Read deps from the manifest, not by # instantiating the plugin class (manifest is the single source of # truth; instantiating fires __init__ side effects unnecessarily). manifest = self.loader.load_manifest(name) for dep in manifest.get('dependencies', []): if not self.registry.is_enabled(dep): logger.error(f"Cannot enable {name}: {dep} is not enabled") return False self.registry.enable(name) # Surface (do not auto-apply) a plugin chain that is ahead of the DB, so # an operator enabling a plugin knows to run `flask plugin upgrade-all`. try: if self.migration_manager and \ self.migration_manager.has_unapplied_migrations(name): logger.warning( f"Plugin {name} has unapplied migrations; " f"run 'flask plugin upgrade-all'" ) except Exception: logger.debug(f"Could not check migration state for {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: self._seed_plugin_permissions(plugin) self._seed_plugin_settings(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.""" self.registry.refresh() if not self.registry.is_enabled(name): logger.info(f"Plugin {name} is already disabled") return True if self._is_core_tier(name): logger.error(f"Cannot disable {name}: it is a core-tier plugin") return False # Refuse if any ENABLED plugin depends on this one (a disabled dependent # is not running, so it does not block). Manifests read from disk. dependents = self._installed_dependents(name, enabled_only=True) if dependents: logger.error( f"Cannot disable {name}: {', '.join(dependents)} depend(s) 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 _dependency_closure(self, names: List[str]) -> List[str]: """Chosen plugins plus their hard-dependency closure, dependencies first. Post-order DFS over manifest `dependencies`, so the returned order is safe to install/enable top to bottom (a dependency always precedes the plugin that needs it). Deduplicated. """ closure: List[str] = [] seen = set() def add(name): if name in seen: return seen.add(name) try: deps = self.loader.load_manifest(name).get('dependencies', []) except PluginError: deps = [] for dep in deps: add(dep) closure.append(name) for name in names: add(name) return closure def apply_profile(self, plugins: List[str], locked: Optional[List[str]] = None) -> Dict[str, List[str]]: """Install AND enable exactly the chosen plugins plus their dependency closure, in dependency order. Declarative replacement for the hand-ordered install/enable sequences in the deploy runbooks (which could enable a plugin that was never installed). Idempotent: already-installed/enabled plugins are left as-is. This does NOT remove anything absent from the list - removal stays an explicit, separate operation. `locked` is accepted for forward compatibility (a future guard against removing a site-mandated plugin) and is currently informational. Raises PluginError if the profile names a plugin (or pulls in a dependency) that does not exist on disk. Returns {installed: [...], enabled: [...], already: [...]}. """ available = set(self.loader.discover_plugins()) unknown = [p for p in plugins if p not in available] if unknown: raise PluginError( f"Profile names unknown plugins: {', '.join(sorted(unknown))}") order = self._dependency_closure(plugins) missing_deps = [p for p in order if p not in available] if missing_deps: raise PluginError( f"Missing dependency plugins: {', '.join(sorted(missing_deps))}") result: Dict[str, List[str]] = { 'installed': [], 'enabled': [], 'already': []} for name in order: changed = False if not self.registry.is_installed(name): if self.install_plugin(name): result['installed'].append(name) changed = True if not self.registry.is_enabled(name): if self.enable_plugin(name): result['enabled'].append(name) changed = True if not changed: result['already'].append(name) return result 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() def get_service(self, name: str): """Resolve a service exposed by an enabled plugin via get_services(). Consumer for the BasePlugin.get_services hook: searches enabled plugins for one that registers `name` and returns the registered value (a service class or factory). Returns None if no enabled plugin provides it. This is how one plugin obtains another's service (e.g. the Zabbix service). """ for plugin_name, plugin in self.get_all_plugins().items(): if not self.registry.is_enabled(plugin_name): continue try: services = plugin.get_services() or {} except Exception: continue if name in services: return services[name] return None # Global plugin manager instance plugin_manager = PluginManager()