Optimizes niceness and cpulimit usage

SCRATCHPAD.md

@@ -14,6 +14,7 @@
 - `FileProperties` now uses one cached `ffprobe -show_format -show_streams -of json` call per source file, and the combined payload was confirmed against the Dragonball asset to satisfy both previous probe call sites fully.
 - Database startup now bootstraps schema only when required tables are actually missing, while version enforcement still runs on ordinary DB-backed context creation.
 - Helper filename and rich-text utilities now use compiled raw regexes plus translate-based filename filtering, with unit coverage for TMDB suffix rewriting and Rich color stripping.
+- Process resource limiting now has explicit disabled/default states in the CLI and requirements, and combined CPU-plus-niceness wrapping now executes as `cpulimit -- nice -n ... <command>` instead of a less explicit prefix chain.
 - FFX logger setup now reuses named handlers, and fallback logger access no longer mutates handlers in ordinary constructors and helpers.
 - The process wrapper now uses `subprocess.run(...)` with centralized command formatting plus stable timeout and missing-command error mapping.
 - Active ORM controllers now use single-query accessors instead of paired `count()` plus `first()` lookups.
@@ -87,15 +88,6 @@
   - Faster contributor onboarding.
   - Easier CI adoption later.
 
-7. Process resource limiting semantics could be clearer
-- [`src/ffx/process.py`](/home/osgw/.local/src/codex/ffx/src/ffx/process.py) prepends `nice` and `cpulimit` directly when values are set.
-- Optimization:
-  - Validate and document effective behavior for combined `nice` + `cpulimit`.
-  - Consider explicit no-limit vs configured-limit states in the CLI and requirements.
-- Expected value:
-  - Fewer surprises in production-like runs.
-  - Easier support for user-reported performance behavior.
-
 ## Open
 
 - Should optimization work focus first on operator-perceived latency, internal maintainability, or correctness-risk cleanup that also has performance upside?

requirements/architecture.md

@@ -42,7 +42,7 @@
   - SQLite via SQLAlchemy ORM, with schema rooted in shows, patterns, tracks, media tags, track tags, shifted seasons, and generic properties.
   - A configuration JSON file supplies optional path, metadata-filtering, and filename-template settings.
 - Integration adapters:
-  - Process execution wrapper for `ffmpeg`, `ffprobe`, `nice`, and `cpulimit`.
+  - Process execution wrapper for `ffmpeg`, `ffprobe`, `nice`, and `cpulimit`, with explicit disabled states for niceness and CPU limiting and a combined `cpulimit -- nice -n ... <command>` execution shape when both limits are configured.
   - HTTP adapter for TMDB via `requests`.
 
 ## Data And Interface Notes

requirements/project.md

@@ -62,6 +62,10 @@
 - The system shall support optional TMDB lookups to resolve show names, years, and episode titles when a show ID, season, and episode are available.
 - The system shall generate output filenames from show metadata, season and episode indices, and episode names using the configured filename template.
 - The system shall allow CLI overrides for stream languages, stream titles, default and forced tracks, stream order, TMDB show and episode data, output directory, label prefix, and processing resource limits.
+- Processing resource limit rules:
+  - `--nice` shall accept niceness values from `-20` through `19`; omitting the option shall disable niceness adjustment.
+  - `--cpu` shall accept CPU limit values from `1` through `99`; omitting the option shall disable CPU limiting.
+  - When both limits are configured, the process wrapper shall execute the target command through `cpulimit` around a `nice -n ...` invocation so both limits apply to the launched media command.
 - The system shall support extracting streams into separate files via `unmux` and reporting suggested crop parameters via `cropdetect`.
 - The system shall handle invalid input and system failures gracefully by logging warnings or raising `click` errors for missing files, invalid media, missing TMDB credentials, incompatible database versions, and ambiguous track dispositions when prompting is disabled.
 

src/ffx/cli.py

@@ -32,6 +32,24 @@ if TYPE_CHECKING:
 LIGHTWEIGHT_COMMANDS = {None, 'version', 'help', 'configure_workstation', 'upgrade'}
 
 
+def normalizeNicenessOption(ctx, param, value):
+    from ffx.process import normalizeNiceness
+
+    try:
+        return normalizeNiceness(value)
+    except ValueError as ex:
+        raise click.BadParameter(str(ex)) from ex
+
+
+def normalizeCpuOption(ctx, param, value):
+    from ffx.process import normalizeCpuPercent
+
+    try:
+        return normalizeCpuPercent(value)
+    except ValueError as ex:
+        raise click.BadParameter(str(ex)) from ex
+
+
 
 @click.group()
 @click.pass_context
@@ -194,6 +212,7 @@ def upgrade(ctx, branch):
 
     commandSequences += [
         ['git', 'pull'],
+        [bundlePipPath, 'install', '--upgrade', 'pip', 'setuptools', 'wheel'],
         [bundlePipPath, 'install', '--editable', '.'],
     ]
 
@@ -257,8 +276,22 @@ def getUnmuxSequence(trackDescriptor: TrackDescriptor, sourcePath, targetPrefix,
 @click.option('-l', '--label', type=str, default='', help='Label to be used as filename prefix')
 @click.option("-o", "--output-directory", type=str, default='')
 @click.option("-s", "--subtitles-only", is_flag=True, default=False)
-@click.option('--nice', type=int, default=99, help='Niceness of started processes')
-@click.option('--cpu', type=int, default=0, help='Limit CPU for started processes to percent')
+@click.option(
+    '--nice',
+    type=int,
+    default=None,
+    callback=normalizeNicenessOption,
+    show_default='disabled',
+    help='Adjust niceness of started processes (-20..19). Omit to disable; 99 also disables.',
+)
+@click.option(
+    '--cpu',
+    type=int,
+    default=None,
+    callback=normalizeCpuOption,
+    show_default='disabled',
+    help='Limit CPU percent of started processes (1..99). Omit to disable; 0 also disables.',
+)
 def unmux(ctx,
             paths,
             label,
@@ -334,8 +367,22 @@ def unmux(ctx,
 @click.pass_context
 
 @click.argument('paths', nargs=-1)
-@click.option('--nice', type=int, default=99, help='Niceness of started processes')
-@click.option('--cpu', type=int, default=0, help='Limit CPU for started processes to percent')
+@click.option(
+    '--nice',
+    type=int,
+    default=None,
+    callback=normalizeNicenessOption,
+    show_default='disabled',
+    help='Adjust niceness of started processes (-20..19). Omit to disable; 99 also disables.',
+)
+@click.option(
+    '--cpu',
+    type=int,
+    default=None,
+    callback=normalizeCpuOption,
+    show_default='disabled',
+    help='Limit CPU percent of started processes (1..99). Omit to disable; 0 also disables.',
+)
 def cropdetect(ctx,
             paths,
             nice,
@@ -479,8 +526,22 @@ def checkUniqueDispositions(context, mediaDescriptor: MediaDescriptor):
 @click.option("--no-signature", is_flag=True, default=False)
 @click.option("--keep-mkvmerge-metadata", is_flag=True, default=False)
 
-@click.option('--nice', type=int, default=99, help='Niceness of started processes')
-@click.option('--cpu', type=int, default=0, help='Limit CPU for started processes to percent')
+@click.option(
+    '--nice',
+    type=int,
+    default=None,
+    callback=normalizeNicenessOption,
+    show_default='disabled',
+    help='Adjust niceness of started processes (-20..19). Omit to disable; 99 also disables.',
+)
+@click.option(
+    '--cpu',
+    type=int,
+    default=None,
+    callback=normalizeCpuOption,
+    show_default='disabled',
+    help='Limit CPU percent of started processes (1..99). Omit to disable; 0 also disables.',
+)
 
 @click.option('--rename-only', is_flag=True, default=False, help='Only renaming, no recoding')
 

src/ffx/process.py

@@ -6,29 +6,72 @@ from .logging_utils import get_ffx_logger
 
 COMMAND_TIMED_OUT_RETURN_CODE = 124
 COMMAND_NOT_FOUND_RETURN_CODE = 127
+MIN_NICENESS = -20
+MAX_NICENESS = 19
+DISABLED_NICENESS_SENTINEL = 99
+MIN_CPU_PERCENT = 1
+MAX_CPU_PERCENT = 99
+DISABLED_CPU_PERCENT_SENTINEL = 0
 
 
 def formatCommandSequence(commandSequence: Iterable[str]) -> str:
     return shlex.join([str(token) for token in commandSequence])
 
 
+def normalizeNiceness(niceness) -> int | None:
+    if niceness is None:
+        return None
+
+    niceness = int(niceness)
+    if niceness == DISABLED_NICENESS_SENTINEL:
+        return None
+
+    if niceness < MIN_NICENESS or niceness > MAX_NICENESS:
+        raise ValueError(
+            f"Niceness must be between {MIN_NICENESS} and {MAX_NICENESS}, "
+            + f"or {DISABLED_NICENESS_SENTINEL} to disable."
+        )
+
+    return niceness
+
+
+def normalizeCpuPercent(cpuPercent) -> int | None:
+    if cpuPercent is None:
+        return None
+
+    cpuPercent = int(cpuPercent)
+    if cpuPercent == DISABLED_CPU_PERCENT_SENTINEL:
+        return None
+
+    if cpuPercent < MIN_CPU_PERCENT or cpuPercent > MAX_CPU_PERCENT:
+        raise ValueError(
+            f"CPU limit must be between {MIN_CPU_PERCENT} and {MAX_CPU_PERCENT}, "
+            + f"or {DISABLED_CPU_PERCENT_SENTINEL} to disable."
+        )
+
+    return cpuPercent
+
+
 def getWrappedCommandSequence(commandSequence: List[str], context: dict = None) -> List[str]:
     """
-    niceness -20 bis +19
-    cpu_percent: 1 bis 99
+    niceness: -20 to 19, disabled when unset
+    cpu_percent: 1 to 99, disabled when unset
+
+    When both limits are configured, cpulimit wraps a nice-adjusted command:
+    cpulimit -l <cpu> -- nice -n <niceness> <command>
     """
 
-    niceSequence = []
+    resourceLimits = (context or {}).get('resource_limits', {})
+    niceness = normalizeNiceness(resourceLimits.get('niceness'))
+    cpu_percent = normalizeCpuPercent(resourceLimits.get('cpu_percent'))
+    wrappedCommandSequence = [str(token) for token in commandSequence]
 
-    niceness = int((context or {}).get('resource_limits', {}).get('niceness', 99))
-    cpu_percent = int((context or {}).get('resource_limits', {}).get('cpu_percent', 0))
+    if niceness is not None:
+        wrappedCommandSequence = ['nice', '-n', str(niceness)] + wrappedCommandSequence
+    if cpu_percent is not None:
+        wrappedCommandSequence = ['cpulimit', '-l', str(cpu_percent), '--'] + wrappedCommandSequence
 
-    if niceness >= -20 and niceness <= 19:
-        niceSequence += ['nice', '-n', str(niceness)]
-    if cpu_percent >= 1:
-        niceSequence += ['cpulimit', '-l', str(cpu_percent), '--']
-
-    return niceSequence + [str(token) for token in commandSequence]
+    return wrappedCommandSequence
 
 
 def getProcessTimeoutSeconds(context: dict = None, timeoutSeconds: float = None):

tests/unit/test_cli_upgrade.py

@@ -87,6 +87,7 @@ class UpgradeCommandTests(unittest.TestCase):
                 ['git', 'reset', '--hard', 'HEAD'],
                 ['git', 'checkout', 'main'],
                 ['git', 'pull'],
+                [pip_path, 'install', '--upgrade', 'pip', 'setuptools', 'wheel'],
                 [pip_path, 'install', '--editable', '.'],
             ],
             [call[0] for call in subprocess_calls],

tests/unit/test_process.py

@@ -15,6 +15,9 @@ from ffx.process import (  # noqa: E402
     COMMAND_NOT_FOUND_RETURN_CODE,
     COMMAND_TIMED_OUT_RETURN_CODE,
     executeProcess,
+    getWrappedCommandSequence,
+    normalizeCpuPercent,
+    normalizeNiceness,
 )
 
 
@@ -47,6 +50,39 @@ class ProcessTests(unittest.TestCase):
         self.assertIn("Command timed out", err)
         self.assertIn(sys.executable, err)
 
+    def test_get_wrapped_command_sequence_leaves_command_unwrapped_when_limits_disabled(self):
+        wrapped = getWrappedCommandSequence(
+            ["ffmpeg", "-i", "input.mkv"],
+            context={"resource_limits": {"niceness": None, "cpu_percent": None}},
+        )
+
+        self.assertEqual(["ffmpeg", "-i", "input.mkv"], wrapped)
+
+    def test_get_wrapped_command_sequence_wraps_nice_when_configured(self):
+        wrapped = getWrappedCommandSequence(
+            ["ffmpeg", "-i", "input.mkv"],
+            context={"resource_limits": {"niceness": 5, "cpu_percent": None}},
+        )
+
+        self.assertEqual(["nice", "-n", "5", "ffmpeg", "-i", "input.mkv"], wrapped)
+
+    def test_get_wrapped_command_sequence_wraps_cpulimit_around_nice_when_both_configured(self):
+        wrapped = getWrappedCommandSequence(
+            ["ffmpeg", "-i", "input.mkv"],
+            context={"resource_limits": {"niceness": 5, "cpu_percent": 42}},
+        )
+
+        self.assertEqual(
+            ["cpulimit", "-l", "42", "--", "nice", "-n", "5", "ffmpeg", "-i", "input.mkv"],
+            wrapped,
+        )
+
+    def test_normalize_niceness_accepts_disabled_sentinel(self):
+        self.assertIsNone(normalizeNiceness(99))
+
+    def test_normalize_cpu_percent_accepts_disabled_sentinel(self):
+        self.assertIsNone(normalizeCpuPercent(0))
+
 
 if __name__ == "__main__":
     unittest.main()