Optimizes niceness and cpulimit usage

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):