Commit Graph
2 Commits
Author SHA1 Message Date
0c5b9c57d3 fix: keep low-memory boards reachable under load (#464)
* fix(service): survive corrupt health cache and clean exits

Three independent failure modes that each end with a dark panel and no
automatic recovery.

1. PluginHealthTracker._load_health_state returned the cached value
   verbatim. If that value is not a dict, every caller raises
   AttributeError: 'list' object has no attribute 'get' — during
   DisplayController.__init__, so the process dies before the display
   loop starts. systemd restarts it, the same bad entry is read back
   from disk, and it dies again: an unattended restart loop that
   survives reboots because the cause is persisted. Observed in the
   field with plugin_health:<id> holding an unrelated plugin's list
   payload. Now non-dict entries are discarded with a warning and the
   defaults are rebuilt.

2. ledmatrix.service used Restart=on-failure, so any exit with status 0
   left the unit stopped and the panel dark indefinitely — systemd
   treats it as success and never brings it back. Restart=always.

3. ledmatrix-wifi-monitor.service used StandardOutput=syslog, which
   systemd has marked obsolete; it warns and rewrites it to journal on
   every load.

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

* perf(memory): size the cache to the board and stop reinstalling deps

On a 1GB Pi 3B+ the display process settles around 600MB RSS of 905MB
total. When the remaining headroom runs out the failure is not a clean
crash: fork() starts returning ENOMEM, so sshd accepts connections and
closes them before its banner, timer jobs stop running, and the panel
goes dark, while already-resident processes keep serving normally. The
board looks healthy from outside and cannot be logged into. Only a power
cycle clears it.

Three contributing causes:

- MemoryCache had a fixed 1000-entry ceiling. Entries are parsed API
  payloads of tens of KB, so one ceiling cannot serve both a 512MB Zero
  2 W and an 8GB Pi 5. Now scaled from MemTotal (150 entries at <=1GB,
  1500 at >=8GB), overridable with LEDMATRIX_CACHE_MAX_ENTRIES.

- requirements_are_satisfied() returned False for any requirement with
  extras, so a plugin depending on python-socketio[client] re-ran pip on
  every single start: ~8s, a network dependency, and a 100-200MB spike
  at the least convenient moment. During a restart loop it repeats for
  each restart. Extras are now resolved one level deep against installed
  metadata, keeping the conservative "anything unverifiable falls
  through to pip" contract.

- ledmatrix.service had no memory ceiling. MemoryMax=85% expressed as a
  percentage so one unit file suits every board. Note this needs the
  memory cgroup controller, which Pi firmware disables by default;
  first_time_install.sh now adds cgroup_enable=memory to cmdline.txt,
  and the unit file documents how to verify it took effect.

first_time_install.sh also enables persistent journald storage (capped
at 64M). Default storage is volatile, so every reboot destroys the logs
that would explain why the board rebooted.

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

* docs: guidance for 512MB and 1GB boards

Documents the memory ceiling on small boards and, more usefully, what
running into it actually looks like: sshd accepting connections and
closing them before the banner, the web UI still responding normally,
clean ping, a dark panel, and a wrong clock after the next boot. None of
those read as "out of memory", which makes the failure hard to identify
from the symptoms.

Cross-referenced from SSH_UNAVAILABLE_AFTER_INSTALL.md, since "I can't
SSH in any more" is how most people will first meet this.

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

* fix: address review findings on the low-memory work

Nine CodeRabbit findings, five in code.

**Health state (the one that matters).** The non-dict guard did not cover a
dict missing fields the callers index directly, which is the shape actually
seen in the wild: a record carrying only circuit_state produced
`plugin clock-simple operation failed: 'circuit_state'` about fifty times a
minute with the panel frozen. The record is now completed against the
defaults per field rather than trusted or discarded wholesale. Per field
matters: a first pass rejected any incomplete record outright, which reset a
tripped breaker and real failure counts to healthy because one optional
field was absent -- an existing test caught it. Values of the wrong type
(a counter persisted as a string, an unknown circuit_state) fall back
individually, valid neighbours survive, and newer fields the schema has
grown since (degraded, degraded_reason) are carried through untouched.

**Cache ceiling.** MemoryCache.set() accepted entries without bound between
cleanup sweeps, which run every 300s by default, so a burst could take the
cache far past max_size -- the unbounded growth the limit exists to stop.
Eviction now runs under the same lock on every write, sharing one helper
with the periodic sweep so the two cannot drift.

**Installer, cgroups.** Only cgroup_enable=memory was checked, so a board
carrying that without cgroup_memory=1 reported success and got no change,
leaving MemoryMax= inert. Each parameter is now checked and appended
independently; verified against all four combinations, single line preserved.

**Installer, journald.** Persistence was inferred from /var/log/journal being
non-empty, which proves neither Storage=persistent nor a size cap -- the
directory survives a switch back to volatile. The effective configuration is
read instead (systemd-analyze cat-config, falling back to the conf files),
and an explicitly configured SystemMaxUse is preserved rather than
overwritten. Verified across volatile, persistent-without-cap,
persistent-with-user-cap, cap-without-storage, and commented-only configs.

**Dependency extras.** _extras_are_satisfied stopped at one level, so a
gated dependency that itself requests an extra (requests[socks]) passed on
the base distribution's version while the extra's own dependency was
missing, and pip was skipped. It now recurses, with a visited
(distribution, extras) set so a cycle terminates.

Docs: both kernel command-line paths documented (the installer falls back to
/boot/cmdline.txt), daemon-reload and restart added after the systemd
override example, memory exhaustion added to the SSH summary with its
power-cycle-only recovery, and a language on the fenced block for MD040.

Tests: five for the health-state repair including the exact wild shape and
that record_failure/record_success no longer raise against it, and one for
the cache ceiling. Both mutation-checked. Full suite 2927 passed, with the
one pre-existing tmpfs failure that also fails on main.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01STMbQE4YctTacQXfbYqKuW

* fix: harden the health-state repair and confirm journald took effect

Second review round; all three findings were valid and two were bugs in the
repair added last commit.

The repair could raise out of itself. An unhashable circuit_state (a list or
dict on disk) hit `value in {...}` and raised TypeError -- from the code
whose whole job is to stop a malformed record crashing the caller. It now
requires a str before the membership test.

bool is a subclass of int, so True passed the timestamp check and then
compared as 1.0: enough to expire a cooldown the instant the breaker opened,
while False would stop the elapsed check firing at all. Timestamps now
exclude bool explicitly.

The regression test for the original crash was seeded with a record that
*contained* circuit_state, so it passed against the old raw-return behaviour
too -- the counters are read with .get(), so circuit_state is the only field
whose absence used to raise. Reseeded to omit it, and it now fails against
raw-return as intended.

journald: drop-ins apply in lexical order, so a local file sorting after
ledmatrix-persistent.conf still wins and writing ours proves nothing. The
effective Storage is re-read afterwards and a warning naming the diagnostic
command is printed if persistence is still not active, rather than reporting
a success that was not verified.

Full suite 2934 passed, same single pre-existing tmpfs failure.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01STMbQE4YctTacQXfbYqKuW

---------

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
2026-08-19 12:28:22 -04:00
3b93024993 feat: activate dormant plugin health/metrics subsystem and surface it in the web UI (#388)
* feat(plugin-system): activate dormant plugin health & metrics subsystem

PluginManager shipped a fully-built health tracker, resource monitor and
circuit breaker that were never instantiated (health_tracker/resource_monitor
were left as None), so the circuit breaker never engaged and the existing
health/metrics API routes always returned "not available".

- DisplayController now wires a PluginHealthTracker and PluginResourceMonitor
  onto the plugin manager, enabling the circuit breaker (a repeatedly-failing
  plugin's update() is skipped after consecutive failures, then retried after
  a cooldown) and per-plugin execution-time metrics. Both persist to the
  shared cache.
- load_plugin() now validates each plugin's config against its JSON schema in
  a strictly warn/degrade-only way: a violation logs a warning and flags the
  plugin degraded in the health tracker, but never changes whether the plugin
  loads or its pass/fail behaviour. Adds PluginHealthTracker.set_degraded(),
  which never touches the circuit breaker.
- ResourceMonitor CPU/memory sampling now reuses a cached psutil.Process and
  reads cpu_percent(interval=None), so monitoring no longer blocks ~100ms per
  call on the display loop's update path.
- Fix DiskCache.get() raising TypeError for max_age=None ("never expires"),
  which silently discarded persisted plugin health/metrics on read and thus
  broke cross-process and post-restart surfacing.
- Fix two dead PluginManager helpers that called non-existent tracker methods.

Tests: new test_resource_monitor, test_plugin_health,
test_plugin_manager_schema_soft; extended test_cache_manager and
test_display_controller.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UvTav268UXv44ub9K11LYq

* feat(web-ui): surface plugin health, metrics and load state

With the health/metrics subsystem now active in the display service, expose it
in the web UI (which runs as a separate process from the display loop):

- Wire a health tracker / resource monitor backed by the shared on-disk cache
  into the web process so /api/v3/plugins/health and /plugins/metrics read the
  data the display service persists.
- Build those route responses per installed plugin id (the tracker's in-memory
  view is empty in a fresh web process) so cross-process data is included.
- Add state + error_info to /plugins/installed entries so the UI can show why a
  plugin isn't running instead of just loaded:false.
- Add a "Plugin Health" panel to the Tools page (circuit status, avg/max update
  time, update count, last error) plus PluginAPI.getPluginMetrics().

Tests: route-level tests for the health/metrics endpoints in test_web_api.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UvTav268UXv44ub9K11LYq

* fix(plugin-metrics): refresh cross-process health/metrics reads; type hints

Addresses CodeRabbit review on #388:

- Major: the web process's health/resource trackers cached the first persisted
  read in an in-memory dict (and the CacheManager memory tier held max_age=None
  entries indefinitely), so a long-lived web process showed the first snapshot
  and never reflected the display service's later updates. Add an opt-in
  force_reload path (get_health_summary/get_health_state/_load_health_state and
  get_metrics_summary/get_metrics) that bypasses the in-memory copy and, via a
  new memory_ttl passthrough on CacheManager.get, the cache manager's memory
  tier — so each /plugins/health and /plugins/metrics poll reads fresh persisted
  state. Default behaviour (force_reload=False) is unchanged for the display
  process and existing callers.
- Minor: DiskCache.get type hint is now Optional[int] with the None ("never
  expires") semantics documented, matching MemoryCache.get.

Tests: new force_reload staleness cases in test_plugin_health and
test_resource_monitor.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UvTav268UXv44ub9K11LYq

---------

Co-authored-by: Claude <noreply@anthropic.com>
2026-07-09 07:54:18 -04:00