Files
shopdb-flask/shopdb/plugins/__init__.py
cproudlock 593dd46525 Show the kiosk label prefix, and let a plugin declare the settings it owns
Three defects, all found on printedparts_label_prefix, all one root cause:
nothing in the framework knew that setting existed.

The parts kiosk runs logged out. An unauthenticated read of a setting is
limited to an allowlist, the key was not on it, so the kiosk got a 404 and
fell back to no prefix. An admin previewing the same page while logged in saw
the prefix, which is why it looked like it worked.

The same setting also looked like it would not save. The row did not exist on
a site that installed the plugin before the setting was added, so the first
save created it - under the placeholder category the settings API uses for
keys it does not recognise, where the plugin's settings page, which lists by
category, could no longer see it. The value was in the database the whole
time.

And the row was missing in the first place because seeding ran from
on_install / on_enable, which fire only on a state transition. Neither runs
again on an upgrade, so a setting added in a later plugin version never
reached a site that installed an earlier one. The comment claiming enable ran
every upgrade cycle was simply wrong.

A plugin now declares the settings it owns in get_settings_defaults(): key,
default, type, category, description, and whether a logged-out page may read
it. The framework seeds declared keys at install, at enable, and on every
flask plugin upgrade-all; files a first-time write under the declared
category; re-homes any row left in the placeholder category, value untouched;
and answers an anonymous read for keys marked public. Core carries no list of
any plugin's keys.

Contract 0.16.0 (additive optional hook). printedparts and printers move to
the hook and floor their core_version at 0.16.0. The dev database had two rows
in the misfiled state (printedparts_alert_email, employee_db_host); the first
repairs itself on the next upgrade pass.
2026-08-06 18:17:49 -04:00

647 lines
26 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
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
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.<name>.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)
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 discovered plugin.
Returns {plugin_name: 'ok'|'no-migrations'|<error str>}. 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()
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:
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 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 _register_plugin_components(self, plugin: BasePlugin) -> None:
"""Register plugin's blueprint, models, CLI commands, etc."""
# 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 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),
})
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:
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."""
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. 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."""
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()