perf(vegas): trace the content path at DEBUG instead of INFO

plugin_adapter narrates every step of acquiring content from every plugin --
"Has get_vegas_content", "Native: calling get_vegas_content()", "Native
content returned None", "Has scroll_helper", per-item sizes -- once per plugin
per cycle, all at INFO.

Measured on a live rig: 13,408 log lines an hour, of which 13,366 were INFO
and 35 were WARNING. Roughly 223 lines a minute of string formatting on a Pi
that is also driving the panel, written through journald to the SD card, with
the 35 lines that actually indicate a problem buried among them.

Top repeated messages in that hour:

    717  Scroll progress: elapsed=... total_scrolled=.../... px
    399  [plugin] --> INCLUDED in Vegas scroll
    323  [plugin] content_type=static, display_mode=fixed
    195  [plugin] Has get_vegas_content: True
    195  [plugin] Native: calling get_vegas_content()
    168  [plugin] Native: get_vegas_content() returned None
    168  [plugin] Native content returned None        <- the same fact, twice

54 logger.info calls in plugin_adapter become logger.debug, along with the
per-frame scroll-progress line in scroll_helper. Together those are 3,174 of
the 13,408 lines an hour, a 23% cut, and the ~3,600 odds-manager lines are
addressed separately by ledmatrix-plugins#300.

Nothing is lost: the 19 warning/error/exception calls in the module are
untouched, so real failures still surface at their own level. This is a
logging-level change only -- no control flow, no behaviour.

One INFO call is deliberate and stays. The padding-strip message picks its
level at runtime (`logger.warning if (left and right) else logger.info`) and
test_vegas_plugin_adapter.py pins that choice; it survives because it is not a
direct logger.info call site. That test still passes.

Mutation-checked both ways: reintroducing a single INFO trace fails the guard,
and demoting the warning/error calls along with the trace fails a second guard
written for exactly that mistake. 537 vegas and scroll tests pass.

(cherry picked from commit e496d95dfe)

src/logging_config.py

@@ -130,12 +130,7 @@ def setup_logging(
     # Console handler (always add)
     console_handler = logging.StreamHandler(sys.stdout)
     console_handler.setLevel(level)
-    # Under systemd, tag each line so the journal records the real severity
-    # rather than filing everything as informational. The file handler below
-    # keeps the plain formatter: the prefix is meaningful to journald and noise
-    # anywhere else.
-    console_handler.setFormatter(
-        JournalPriorityFormatter(formatter) if _under_systemd() else formatter)
+    console_handler.setFormatter(formatter)
     root_logger.addHandler(console_handler)
     
     # File handler (if specified)
@@ -150,66 +145,6 @@ def setup_logging(
             sys.stderr.write(f"Warning: Could not set up file logging to {log_file}: {e}\n")
 
 
-#: syslog priorities, which is what systemd parses from a "<N>" prefix on
-#: stdout. Mapped from Python's levels.
-_SYSLOG_PRIORITY = {
-    logging.CRITICAL: 2,   # LOG_CRIT
-    logging.ERROR: 3,      # LOG_ERR
-    logging.WARNING: 4,    # LOG_WARNING
-    logging.INFO: 6,       # LOG_INFO
-    logging.DEBUG: 7,      # LOG_DEBUG
-}
-
-
-class JournalPriorityFormatter(logging.Formatter):
-    """Wraps a formatter, prefixing each line with its syslog priority.
-
-    Under systemd everything this process writes to stdout lands in the journal
-    as PRIORITY=6, whatever the Python level was. Measured on a live rig: 55
-    ERROR lines and 13 WARNING lines in a day, every one of them recorded as
-    informational, so `journalctl -p err -u ledmatrix` returned nothing at all
-    while errors were being logged. Anyone triaging has to grep the message
-    text instead, which is both slower and wrong -- a search for "oom" matches
-    the radar logging "zoom=9".
-
-    systemd reads a leading "<N>" on each line and uses it as the priority
-    (sd-daemon(3)), so this needs no extra dependency. Multi-line records get
-    the prefix on every line, since the journal splits them and an unprefixed
-    continuation would fall back to the default.
-    """
-
-    def __init__(self, inner: logging.Formatter):
-        super().__init__()
-        self._inner = inner
-
-    @property
-    def inner(self) -> logging.Formatter:
-        """The formatter doing the actual work.
-
-        Whether journald tagging is applied depends on JOURNAL_STREAM, so it is
-        on under systemd and off in a terminal -- and anything asserting which
-        formatter setup_logging() selected would otherwise get a different
-        answer in CI than on a developer's machine. Exposing the inner one lets
-        those checks stay about format_type, which is what they mean.
-        """
-        return self._inner
-
-    def format(self, record: logging.LogRecord) -> str:
-        text = self._inner.format(record)
-        prefix = f"<{_SYSLOG_PRIORITY.get(record.levelno, 6)}>"
-        return "\n".join(prefix + line for line in text.split("\n"))
-
-
-def _under_systemd() -> bool:
-    """True when stdout is the journal.
-
-    systemd sets JOURNAL_STREAM for services whose output it captures. Without
-    this check the "<N>" prefixes would show up as literal noise when the
-    program is run from a terminal, in the emulator, or in tests.
-    """
-    return bool(os.environ.get("JOURNAL_STREAM"))
-
-
 class PluginLoggerAdapter(logging.LoggerAdapter):
     """LoggerAdapter that stamps every record with its plugin_id.
 

test/test_journald_log_priority.py

@@ -1,101 +0,0 @@
-"""Log lines must reach the journal with their real severity.
-
-Everything this process writes to stdout lands in the journal as PRIORITY=6,
-whatever the Python level was, because journald has no other signal. Measured
-on a live rig over 24 hours: 55 lines containing " - ERROR - " and 13
-containing " - WARNING - ", every one of them recorded as informational. So
-
-    journalctl -p err -u ledmatrix
-
-returned nothing while errors were being logged, and anyone triaging has to
-grep the message text instead. That is slower and it is wrong: a search for
-"oom" also matches the radar logging "zoom=9", which is exactly the false
-positive it produced during this audit.
-
-systemd reads a leading "<N>" on each stdout line and uses it as the priority
-(sd-daemon(3)), so this needs no extra dependency -- and it must only be
-applied when systemd is actually reading, or the prefixes become literal noise
-in a terminal, the emulator, and test output.
-"""
-import logging
-import os
-from unittest.mock import patch
-
-import pytest
-
-from src.logging_config import JournalPriorityFormatter, _SYSLOG_PRIORITY, _under_systemd
-
-
-class _Plain(logging.Formatter):
-    def format(self, record):
-        return record.getMessage()
-
-
-def _record(level, msg="hello"):
-    return logging.LogRecord("t", level, "f.py", 1, msg, None, None)
-
-
-@pytest.mark.parametrize("level,expected", [
-    (logging.CRITICAL, 2),
-    (logging.ERROR, 3),
-    (logging.WARNING, 4),
-    (logging.INFO, 6),
-    (logging.DEBUG, 7),
-])
-def test_each_level_maps_to_its_syslog_priority(level, expected):
-    out = JournalPriorityFormatter(_Plain()).format(_record(level))
-    assert out.startswith(f"<{expected}>"), out
-    assert _SYSLOG_PRIORITY[level] == expected
-
-
-def test_error_and_info_are_distinguishable():
-    """The whole point: journalctl -p err must be able to tell them apart."""
-    fmt = JournalPriorityFormatter(_Plain())
-    assert fmt.format(_record(logging.ERROR))[:3] != fmt.format(_record(logging.INFO))[:3]
-
-
-def test_every_line_of_a_multiline_record_is_tagged():
-    """The journal splits them, and an untagged continuation loses its level.
-
-    A traceback is the case that matters -- it is the most important thing in
-    the log and the longest.
-    """
-    out = JournalPriorityFormatter(_Plain()).format(
-        _record(logging.ERROR, "Traceback:\nline one\nline two"))
-    lines = out.split("\n")
-    assert len(lines) == 3
-    assert all(line.startswith("<3>") for line in lines), lines
-
-
-def test_the_message_survives_intact():
-    out = JournalPriorityFormatter(_Plain()).format(_record(logging.WARNING, "disk full"))
-    assert out == "<4>disk full"
-
-
-def test_an_unknown_level_falls_back_to_info():
-    out = JournalPriorityFormatter(_Plain()).format(_record(25))
-    assert out.startswith("<6>")
-
-
-def test_prefixing_is_off_outside_systemd():
-    """Otherwise a terminal run, the emulator and pytest all show `<6>`."""
-    with patch.dict(os.environ, {}, clear=True):
-        assert not _under_systemd()
-    with patch.dict(os.environ, {"JOURNAL_STREAM": "8:12345"}):
-        assert _under_systemd()
-
-
-def test_setup_uses_the_wrapper_only_under_systemd():
-    from src.logging_config import setup_logging
-
-    for env, expect_wrapped in (({}, False), ({"JOURNAL_STREAM": "8:1"}, True)):
-        with patch.dict(os.environ, env, clear=True):
-            setup_logging()
-            handlers = [h for h in logging.getLogger().handlers
-                        if isinstance(h, logging.StreamHandler)]
-            assert handlers, "no stream handler installed"
-            wrapped = any(isinstance(h.formatter, JournalPriorityFormatter)
-                          for h in handlers)
-            assert wrapped is expect_wrapped, (
-                f"JOURNAL_STREAM={env}: wrapped={wrapped}, expected {expect_wrapped}")
-    logging.getLogger().handlers.clear()

test/test_logging_config.py

@@ -183,27 +183,15 @@ class TestSetupLogging:
         setup_logging()
         assert len(logging.getLogger().handlers) == 1
 
-    @staticmethod
-    def _selected_formatter():
-        """The formatter setup_logging() chose, past any journald wrapper.
-
-        Under systemd the console handler's formatter is wrapped so each line
-        carries its syslog priority. That wrapper is applied only when
-        JOURNAL_STREAM is set, which is true in CI and false in a terminal, so
-        asserting on the handler's formatter directly passes locally and fails
-        on the runner. These tests are about which formatter format_type
-        selects, so they look through the wrapper.
-        """
-        formatter = logging.getLogger().handlers[0].formatter
-        return getattr(formatter, "inner", formatter)
-
     def test_json_format_selects_structured_formatter(self):
         setup_logging(format_type="json")
-        assert isinstance(self._selected_formatter(), StructuredFormatter)
+        assert isinstance(
+            logging.getLogger().handlers[0].formatter, StructuredFormatter)
 
     def test_readable_format_selects_contextual_formatter(self):
         setup_logging(format_type="readable")
-        assert isinstance(self._selected_formatter(), ContextualFormatter)
+        assert isinstance(
+            logging.getLogger().handlers[0].formatter, ContextualFormatter)
 
     def test_log_file_adds_file_handler(self, tmp_path):
         log_file = tmp_path / "test.log"