mirror of
https://github.com/ChuckBuilds/LEDMatrix.git
synced 2026-08-01 08:48:05 +00:00
4d49b0f892
The display service PNG-encoded its frame to /tmp/led_matrix_preview.png at 5 fps, 24/7 — identical frames, no viewers, per-call imports and a chmod every write. On the devpi baseline the display service idles at ~92% CPU; this was one of its biggest fixed costs. - New pure policy (src/common/snapshot_policy.py, unit-tested off-Pi): WRITE changed frames at full rate only while a viewer is watching, at a 30s idle cadence otherwise; NEVER re-encode unchanged frames — bump mtime (os.utime) every 20s instead, keeping the health check's snapshot-age liveness proxy (60s threshold in api_v3) green. Cross- referencing comments guard the two constants. - Viewer detection: the web SSE display broadcaster (which only runs while browsers are subscribed) touches /tmp/led_matrix_preview_viewer each loop; the display service stats it at most 1/s. On viewer arrival the write clock resets so the first frame lands within ~1s. - Hoisted the per-call pathlib/permission_utils imports; directory permissions ensured once instead of every frame. Claude-Session: https://claude.ai/code/session_01FqzC1nzTWL4kaqgMaQZFam Co-authored-by: Chuck <chuck@example.com> Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
94 lines
3.9 KiB
Python
94 lines
3.9 KiB
Python
"""Tests for the snapshot write policy (src/common/snapshot_policy.py).
|
|
|
|
The invariants that matter:
|
|
- unchanged frames are NEVER re-encoded (the old code PNG-encoded identical
|
|
frames at 5 fps, 24/7)
|
|
- the file mtime never goes stale enough to trip the health check's 60s
|
|
degraded threshold (api_v3 get_hardware_status)
|
|
- a viewer gets full cadence; no viewer drops to the idle keepalive
|
|
"""
|
|
|
|
import os
|
|
import sys
|
|
|
|
import pytest
|
|
|
|
sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
|
|
|
|
from src.common.snapshot_policy import ( # noqa: E402
|
|
IDLE_INTERVAL,
|
|
TOUCH_INTERVAL,
|
|
VIEWER_INTERVAL,
|
|
SnapshotAction,
|
|
decide,
|
|
)
|
|
|
|
|
|
class TestViewerCadence:
|
|
def test_changed_frame_with_viewer_writes_at_full_rate(self):
|
|
assert decide(now=100.0, last_write_ts=100.0 - VIEWER_INTERVAL,
|
|
last_touch_ts=0, viewer_fresh=True,
|
|
frame_changed=True) is SnapshotAction.WRITE
|
|
|
|
def test_changed_frame_with_viewer_respects_min_interval(self):
|
|
assert decide(now=100.0, last_write_ts=100.0 - VIEWER_INTERVAL / 2,
|
|
last_touch_ts=100.0, viewer_fresh=True,
|
|
frame_changed=True) is SnapshotAction.SKIP
|
|
|
|
def test_unchanged_frame_with_viewer_never_writes(self):
|
|
"""A static screen with a viewer must not burn PNG encodes."""
|
|
assert decide(now=100.0, last_write_ts=90.0, last_touch_ts=90.0,
|
|
viewer_fresh=True,
|
|
frame_changed=False) is SnapshotAction.SKIP
|
|
|
|
|
|
class TestIdleCadence:
|
|
def test_changed_frame_without_viewer_waits_for_idle_interval(self):
|
|
assert decide(now=100.0, last_write_ts=100.0 - IDLE_INTERVAL / 2,
|
|
last_touch_ts=100.0, viewer_fresh=False,
|
|
frame_changed=True) is SnapshotAction.SKIP
|
|
|
|
def test_changed_frame_without_viewer_writes_at_idle_rate(self):
|
|
assert decide(now=100.0, last_write_ts=100.0 - IDLE_INTERVAL,
|
|
last_touch_ts=0, viewer_fresh=False,
|
|
frame_changed=True) is SnapshotAction.WRITE
|
|
|
|
|
|
class TestHealthKeepalive:
|
|
def test_stale_mtime_gets_touched(self):
|
|
"""Whatever else happens, mtime must be bumped within TOUCH_INTERVAL
|
|
so the health check (60s threshold) never reads the display as dead."""
|
|
assert decide(now=100.0, last_write_ts=100.0 - TOUCH_INTERVAL,
|
|
last_touch_ts=100.0 - TOUCH_INTERVAL, viewer_fresh=False,
|
|
frame_changed=False) is SnapshotAction.TOUCH
|
|
|
|
def test_touch_applies_with_viewer_too(self):
|
|
"""Viewer watching a static screen: no writes, but health stays green."""
|
|
assert decide(now=100.0, last_write_ts=100.0 - TOUCH_INTERVAL - 1,
|
|
last_touch_ts=100.0 - TOUCH_INTERVAL - 1, viewer_fresh=True,
|
|
frame_changed=False) is SnapshotAction.TOUCH
|
|
|
|
def test_recent_touch_suppresses_another(self):
|
|
assert decide(now=100.0, last_write_ts=0.0,
|
|
last_touch_ts=100.0 - TOUCH_INTERVAL / 2, viewer_fresh=False,
|
|
frame_changed=False) is SnapshotAction.SKIP
|
|
|
|
def test_touch_interval_stays_under_health_threshold(self):
|
|
"""api_v3's hardware status treats snapshot age >= 60s as degraded.
|
|
Keep a 2x margin so scheduling jitter can't trip it."""
|
|
assert TOUCH_INTERVAL <= 30
|
|
|
|
def test_worst_case_mtime_age_is_bounded(self):
|
|
"""Simulate any interleaving: from any state, within one policy call
|
|
after TOUCH_INTERVAL elapses, mtime gets refreshed (WRITE or TOUCH)."""
|
|
for viewer in (True, False):
|
|
for changed in (True, False):
|
|
action = decide(now=1000.0, last_write_ts=900.0,
|
|
last_touch_ts=900.0, viewer_fresh=viewer,
|
|
frame_changed=changed)
|
|
assert action in (SnapshotAction.WRITE, SnapshotAction.TOUCH)
|
|
|
|
|
|
if __name__ == "__main__":
|
|
sys.exit(pytest.main([__file__, "-v"]))
|