Files
LEDMatrix/web_interface/blueprints/api_v3/display.py
T
ChuckandClaude Opus 5 f475038895 fix(cache): web UI can read what the display service caches again (#593)
* fix(cache): web UI can read what the display service caches again

ledmatrix-web.service carried CacheDirectory=ledmatrix. With User= set to
the installing user, systemd re-owns /var/cache/ledmatrix and everything
in it to that user and its primary group whenever the directory's owner
differs -- for a directory root created, on the first start. That erased
the root:ledmatrix setgid layout the installers set up, so every file the
display service (root) wrote afterwards was root:root 0660 and unreadable
by the web interface:

  WARNING - Permission denied loading cache for display_current_state ...

Since #547 install_service.sh renders the web unit from the template, so
every fresh install hit this. Measured on one rig: 392 unreadable files,
and the web UI's display status, on-demand state and plugin health empty.

Existing installs only receive `git pull`, never a reinstalled unit, so
the fix for them is in the code the root display service runs:

- DiskCache.set gives each file the directory's group (when the directory
  is group-writable) and 0660 on the open descriptor before the rename,
  independent of setgid. This also closes a window where a fresh file was
  visible as mkstemp's 0600.
- DiskCache.share_existing_files repairs files an older version left
  behind, once per process from the cleanup thread. It works through
  O_NOFOLLOW descriptors and skips hard links and other users' files: the
  directory is writable by the web user, and root must not be steered
  into changing a file outside it.

For new installs, the web unit drops CacheDirectory=/CacheDirectoryMode=,
and install_web_service.sh stops replacing an existing directory's
ledmatrix group with the user's group.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(web): on-demand and current-display status read the display's latest state

Found testing the cache-permission fix on a rig: once the web interface
could read display_on_demand_state at all, /display/on-demand/status kept
answering "active" for over 100 seconds while the file on disk said
"idle". Both status routes read the display service's keys through the
web process's memory tier, which serves the first copy it read for the
full max_age (120s). Read them with memory_ttl=0, as every other
cross-process reader (plugin health/metrics, the on-demand mailbox)
already does.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(install): re-group the cache dir whenever the web user is outside its group

install_web_service.sh replaced an existing cache directory's group only
when it was root's. A directory in any other group the web user is not a
member of -- root:ledmatrix, for a user who is not in ledmatrix -- was left
alone, and every file root wrote there stayed unreadable to the web
interface. Replace the group whenever the installing user is not in it.

A directory whose group the user is already in (ledmatrix, or the user's
own group where CacheDirectory= left it) is still left as it is: re-grouping
a working directory strands the files already in it on the old group.

When the group does change and root-owned JSON files carrying the old group
are present, try-restart ledmatrix.service so DiskCache.share_existing_files
re-groups them through its symlink- and hard-link-safe path, rather than a
recursive chgrp.

Verified under WSL's systemd for seven directory states (user group,
ledmatrix member, ledmatrix non-member with and without root files,
root:root, missing, unnamed gid); the previous version left the non-member
case unchanged.

Addresses CodeRabbit review on #593.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
2026-09-17 12:38:39 -04:00

323 lines
15 KiB
Python

"""Display control, on-demand playback and preview.
Routes decorate the shared `api_v3` Blueprint from ._common, so their
endpoint names are unchanged by living here.
"""
from web_interface.blueprints.api_v3 import (
_ensure_cache_manager, _ensure_display_service_running,
_get_display_service_status, _stop_display_service, api_v3,
describe_exception, jsonify, logger, os, request, uuid,
)
import web_interface.blueprints.api_v3 as _pkg
# Read through the module rather than bound by value: tests patch these
# as module attributes, and a value binding would not see the patch.
# Several are also called from helpers that live in __init__, so the
# package is the only patch point that covers every caller.
@api_v3.route('/display/current', methods=['GET'])
def get_display_current():
"""Get current display state"""
try:
import base64
from PIL import Image
import io
snapshot_path = "/tmp/led_matrix_preview.png"
# Get display dimensions from config: the logical size DisplayManager
# renders at, so double-sided setups preview one screen
from src.display_geometry import logical_size
try:
config = api_v3.config_manager.load_config() if api_v3.config_manager else {}
width, height = logical_size(config)
except Exception:
width, height = logical_size({})
# Try to read snapshot file
image_data = None
if os.path.exists(snapshot_path):
try:
with Image.open(snapshot_path) as img:
# Convert to PNG and encode as base64
buffer = io.BytesIO()
img.save(buffer, format='PNG')
image_data = base64.b64encode(buffer.getvalue()).decode('utf-8')
except Exception as img_err:
# File might be being written or corrupted, return None
pass
display_data = {
'timestamp': _pkg.time.time(),
'width': width,
'height': height,
'image': image_data # Base64 encoded image data or None if unavailable
}
return jsonify({'status': 'success', 'data': display_data})
except Exception as e:
logger.error('Unhandled exception', exc_info=True)
return jsonify({'status': 'error', 'message': 'An error occurred; see logs for details', 'details': describe_exception(e)}), 500
@api_v3.route('/display/modes', methods=['GET'])
def get_display_modes():
"""Every display mode that can be requested on-demand, with its plugin.
/plugins/installed carries no mode information, so anything driving the
display from outside the web UI (the Home Assistant MQTT bridge, a script)
had to read each plugin's manifest.json off disk and reimplement the
fallbacks in PluginManager.get_plugin_display_modes to do it. This is the
same list the force-display dialog offers, from the source that owns it.
Knowing each mode's plugin_id also matters because /display/on-demand/start
falls back to find_plugin_for_mode when plugin_id is omitted, and that
lookup only sees modes declared in a static manifest -- a plugin whose
modes are generated (each installed Starlark app is one) 404s there.
Sending the plugin_id from this list skips the lookup entirely.
Query params:
include_disabled: '1' to list modes of disabled plugins too. They can
still be requested on-demand -- the controller enables the plugin
for the duration -- so they are reported with enabled: false
rather than omitted.
"""
try:
if not api_v3.plugin_manager:
return jsonify({'status': 'error', 'message': 'Plugin manager not initialized'}), 500
# Discovery is lazy and normally triggered by whichever endpoint runs
# first, which is a person opening the dashboard. A caller that never
# visits it would otherwise see an empty list.
api_v3.plugin_manager.discover_plugins()
include_disabled = request.args.get('include_disabled') in ('1', 'true', 'True')
full_config = api_v3.config_manager.load_config() if api_v3.config_manager else {}
modes = []
for plugin_id, manifest in sorted(api_v3.plugin_manager.plugin_manifests.items()):
# A hand-edited or migrated config.json can hold a non-dict under a
# plugin id; DisplayController._reconcile guards the same shape, so
# it happens in practice. Without this, .get() raises AttributeError,
# the loop aborts and the endpoint answers 500 with no modes at all
# -- one bad section would blank every entity the MQTT bridge builds
# from this list.
plugin_config = full_config.get(plugin_id)
if not isinstance(plugin_config, dict):
if plugin_config is not None:
logger.warning(
"Config for plugin %r is %s, not an object; treating it as disabled",
plugin_id, type(plugin_config).__name__)
plugin_config = {}
enabled = bool(plugin_config.get('enabled', False))
if not enabled and not include_disabled:
continue
plugin_name = (manifest or {}).get('name') or plugin_id
plugin_modes = api_v3.plugin_manager.get_plugin_display_modes(plugin_id) or [plugin_id]
for mode in plugin_modes:
# A single-mode plugin's mode is the plugin, so its own name is
# the readable label. Multi-mode plugins have no per-mode name
# anywhere, so the raw mode string is the only thing to show.
modes.append({
'mode': mode,
'plugin_id': plugin_id,
'plugin_name': plugin_name,
'name': plugin_name if len(plugin_modes) == 1 else mode,
'enabled': enabled,
})
return jsonify({'status': 'success', 'data': {'modes': modes}})
except Exception as exc:
# describe_exception, not a bare message: test_web_error_detail.py
# enforces that every handler here returns it, because a device whose
# storage is failing otherwise answers "see logs for details" from the
# log viewer too. It redacts credentials out of the exception text.
# CodeQL flags this as stack-trace exposure across all ~75 handlers;
# it is the project's deliberate, reviewed trade-off.
logger.error('Error in get_display_modes', exc_info=True)
return jsonify({'status': 'error', 'message': 'An error occurred; see logs for details', 'details': describe_exception(exc)}), 500
@api_v3.route('/display/on-demand/status', methods=['GET'])
def get_on_demand_status():
"""Return the current on-demand display state."""
try:
cache = _ensure_cache_manager()
# memory_ttl=0: the display service writes this key, so only the file
# is current. This process's memory tier would keep serving the first
# copy it read for the full max_age -- "active" for two minutes after
# the display had already stopped.
state = cache.get('display_on_demand_state', max_age=120, memory_ttl=0)
if state is None:
state = {
'active': False,
'status': 'idle',
'last_updated': None
}
service_status = _get_display_service_status()
return jsonify({
'status': 'success',
'data': {
'state': state,
'service': service_status
}
})
except Exception as exc:
logger.error('Error in get_on_demand_status', exc_info=True)
return jsonify({'status': 'error', 'message': 'An error occurred; see logs for details', 'details': describe_exception(exc)}), 500
@api_v3.route('/display/on-demand/start', methods=['POST'])
def start_on_demand_display():
"""Request the display controller to run a specific plugin on-demand."""
try:
data = request.get_json(silent=True) or {}
plugin_id = data.get('plugin_id')
mode = data.get('mode')
duration = data.get('duration')
pinned = bool(data.get('pinned', False))
start_service = data.get('start_service', True)
if not plugin_id and not mode:
return jsonify({'status': 'error', 'message': 'plugin_id or mode is required'}), 400
resolved_plugin = plugin_id
resolved_mode = mode
if api_v3.plugin_manager:
if resolved_plugin and resolved_plugin not in api_v3.plugin_manager.plugin_manifests:
return jsonify({'status': 'error', 'message': f'Plugin {resolved_plugin} not found'}), 404
if resolved_plugin and not resolved_mode:
modes = api_v3.plugin_manager.get_plugin_display_modes(resolved_plugin)
resolved_mode = modes[0] if modes else resolved_plugin
elif resolved_mode and not resolved_plugin:
resolved_plugin = api_v3.plugin_manager.find_plugin_for_mode(resolved_mode)
if not resolved_plugin:
return jsonify({'status': 'error', 'message': f'Mode {resolved_mode} not found'}), 404
# Note: On-demand can work with disabled plugins - the display controller
# will temporarily enable them during initialization if needed
# We don't block the request here, but log it for debugging
if api_v3.config_manager and resolved_plugin:
config = api_v3.config_manager.load_config()
plugin_config = config.get(resolved_plugin, {})
if 'enabled' in plugin_config and not plugin_config.get('enabled', False):
logger.info(
"On-demand request for disabled plugin '%s' - will be temporarily enabled",
resolved_plugin,
)
# Set the on-demand request in cache FIRST (before starting service)
# This ensures the request is available when the service starts/restarts
cache = _ensure_cache_manager()
request_id = data.get('request_id') or str(uuid.uuid4())
request_payload = {
'request_id': request_id,
'action': 'start',
'plugin_id': resolved_plugin,
'mode': resolved_mode,
'duration': duration,
'pinned': pinned,
'timestamp': _pkg.time.time()
}
cache.set('display_on_demand_request', request_payload)
# Check if display service is running (or will be started)
service_status = _get_display_service_status()
service_was_running = service_status.get('active', False)
# Stop the display service first to ensure clean state when we will restart it
if service_was_running and start_service:
import time as time_module
logger.debug("Stopping display service before starting on-demand mode")
_stop_display_service()
# Wait a brief moment for the service to fully stop
time_module.sleep(1.5)
logger.debug("Display service stopped, now starting with on-demand request")
if not service_status.get('active') and not start_service:
return jsonify({
'status': 'error',
'message': 'Display service is not running. Please start the display service or enable "Start Service" option.',
'service_status': service_status
}), 400
service_result = None
if start_service:
service_result = _ensure_display_service_running()
# Check if service actually started
if service_result and not service_result.get('active'):
return jsonify({
'status': 'error',
'message': 'Failed to start display service. Please check service logs or start it manually.',
'service_result': service_result
}), 500
# Service was restarted (or started fresh) with on-demand request in cache
# The display controller will read the request during initialization or when it polls
response_data = {
'request_id': request_id,
'plugin_id': resolved_plugin,
'mode': resolved_mode,
'duration': duration,
'pinned': pinned,
'service': service_result
}
return jsonify({'status': 'success', 'data': response_data})
except Exception as exc:
logger.error('Error in start_on_demand_display', exc_info=True)
return jsonify({'status': 'error', 'message': 'An error occurred; see logs for details', 'details': describe_exception(exc)}), 500
@api_v3.route('/display/on-demand/stop', methods=['POST'])
def stop_on_demand_display():
"""Request the display controller to stop on-demand mode."""
try:
data = request.get_json(silent=True) or {}
stop_service = data.get('stop_service', False)
# Set the stop request in cache FIRST
# The display controller will poll this and restart without the on-demand filter
cache = _ensure_cache_manager()
request_id = data.get('request_id') or str(uuid.uuid4())
request_payload = {
'request_id': request_id,
'action': 'stop',
'timestamp': _pkg.time.time()
}
cache.set('display_on_demand_request', request_payload)
# Note: The display controller's _clear_on_demand() will handle the restart
# to restore normal operation with all plugins
service_result = None
if stop_service:
service_result = _stop_display_service()
return jsonify({
'status': 'success',
'data': {
'request_id': request_id,
'service': service_result
}
})
except Exception as exc:
logger.error('Error in stop_on_demand_display', exc_info=True)
return jsonify({'status': 'error', 'message': 'An error occurred; see logs for details', 'details': describe_exception(exc)}), 500
@api_v3.route('/display/current-status', methods=['GET'])
def get_current_display_status():
"""Return the display mode/plugin currently intended to be shown.
Published by the display process (display_controller._publish_current_mode_state)
to the shared cache whenever the active mode changes, so the web UI (e.g. the
System Logs page) can show what's on screen without querying the display
process directly.
"""
try:
cache = _ensure_cache_manager()
# memory_ttl=0: written by the display service; see get_on_demand_status.
state = cache.get('display_current_state', max_age=120, memory_ttl=0)
if state is None:
state = {
'mode': None,
'plugin_id': None,
'last_updated': None,
}
return jsonify({'status': 'success', 'data': state})
except Exception as e:
logger.error('Error in get_current_display_status', exc_info=True)
return jsonify({'status': 'error', 'message': 'An error occurred; see logs for details', 'details': describe_exception(e)}), 500