Files
littlefs/scripts/watch.py
Christopher Haster 2b1738e6d1 scripts: Increased default sleep time to 2 seconds
You forget one script, running in the background, hogging a whole
core, and suddenly watch's default 2 second sleep time makes a lot more
sense...

One of the main motivators for watch.py _was_ for shorter sleep times,
short enough to render realtime animations (watch is limited to 0.1
seconds for some reason?), but this doesn't mean it needs to be the
default. This can still be accomplished by explicitly specifying
-s/--sleep, and we probably don't want the default to hog all the CPU.

The use case for fast sleeps has been mostly replaced by -k/--keep-open
anyways.

For tailpipe.py and tracebd.py it's a bit less clear, but we probably
don't need to be spamming open calls 10 times a second.
2025-02-13 15:51:36 -06:00

319 lines
9.8 KiB
Python
Executable File

#!/usr/bin/env python3
#
# Traditional watch command, but with higher resolution updates and a bit
# different options/output format
#
# Example:
# ./scripts/watch.py -s0.1 date
#
# Copyright (c) 2022, The littlefs authors.
# SPDX-License-Identifier: BSD-3-Clause
#
# prevent local imports
if __name__ == "__main__":
__import__('sys').path.pop(0)
import collections as co
import errno
import fcntl
import io
import os
import pty
import re
import shutil
import struct
import subprocess as sp
import sys
import termios
import time
try:
import inotify_simple
except ModuleNotFoundError:
inotify_simple = None
def openio(path, mode='r', buffering=-1):
# allow '-' for stdin/stdout
if path == '-':
if 'r' in mode:
return os.fdopen(os.dup(sys.stdin.fileno()), mode, buffering)
else:
return os.fdopen(os.dup(sys.stdout.fileno()), mode, buffering)
else:
return open(path, mode, buffering)
if inotify_simple is None:
Inotify = None
else:
class Inotify(inotify_simple.INotify):
def __init__(self, paths):
super().__init__()
# wait for interesting events
flags = (inotify_simple.flags.ATTRIB
| inotify_simple.flags.CREATE
| inotify_simple.flags.DELETE
| inotify_simple.flags.DELETE_SELF
| inotify_simple.flags.MODIFY
| inotify_simple.flags.MOVED_FROM
| inotify_simple.flags.MOVED_TO
| inotify_simple.flags.MOVE_SELF)
# recurse into directories
for path in paths:
if os.path.isdir(path):
for dir, _, files in os.walk(path):
self.add_watch(dir, flags)
for f in files:
self.add_watch(os.path.join(dir, f), flags)
else:
self.add_watch(path, flags)
class RingIO:
def __init__(self, maxlen=None, head=False):
self.maxlen = maxlen
self.head = head
self.lines = co.deque(maxlen=maxlen)
self.tail = io.StringIO()
# trigger automatic sizing
if maxlen == 0:
self.resize(0)
def __len__(self):
return len(self.lines)
def write(self, s):
# note using split here ensures the trailing string has no newline
lines = s.split('\n')
if len(lines) > 1 and self.tail.getvalue():
self.tail.write(lines[0])
lines[0] = self.tail.getvalue()
self.tail = io.StringIO()
self.lines.extend(lines[:-1])
if lines[-1]:
self.tail.write(lines[-1])
def resize(self, maxlen):
self.maxlen = maxlen
if maxlen == 0:
maxlen = shutil.get_terminal_size((80, 5))[1]
if maxlen != self.lines.maxlen:
self.lines = co.deque(self.lines, maxlen=maxlen)
canvas_lines = 1
def draw(self):
# did terminal size change?
if self.maxlen == 0:
self.resize(0)
# copy lines
lines = self.lines.copy()
# pad to fill any existing canvas, but truncate to terminal size
h = shutil.get_terminal_size((80, 5))[1]
lines.extend('' for _ in range(
len(lines),
min(RingIO.canvas_lines, h)))
while len(lines) > h:
if self.head:
lines.pop()
else:
lines.popleft()
# first thing first, give ourself a canvas
while RingIO.canvas_lines < len(lines):
sys.stdout.write('\n')
RingIO.canvas_lines += 1
# write lines from top to bottom so later lines overwrite earlier
# lines, note [xA/[xB stop at terminal boundaries
for i, line in enumerate(lines):
# move cursor, clear line, disable/reenable line wrapping
sys.stdout.write('\r')
if len(lines)-1-i > 0:
sys.stdout.write('\x1b[%dA' % (len(lines)-1-i))
sys.stdout.write('\x1b[K')
sys.stdout.write('\x1b[?7l')
sys.stdout.write(line)
sys.stdout.write('\x1b[?7h')
if len(lines)-1-i > 0:
sys.stdout.write('\x1b[%dB' % (len(lines)-1-i))
sys.stdout.flush()
def main(command, *,
lines=0,
head=False,
cat=False,
sleep=None,
keep_open=False,
keep_open_paths=None,
buffer=False,
ignore_errors=False,
exit_on_error=False):
if not command:
print('usage: %s [options] command' % sys.argv[0],
file=sys.stderr)
sys.exit(-1)
# if we have keep_open_paths, assume user wanted keep_open
if keep_open_paths and not keep_open:
keep_open = True
# figure out the keep_open paths
if keep_open and inotify_simple is not None:
if keep_open_paths:
keep_open_paths = set(keep_open_paths)
else:
# guess inotify paths from command
keep_open_paths = set()
for p in command:
for p in {
p,
re.sub('^-.', '', p),
re.sub('^--[^=]+=', '', p)}:
if p and os.path.exists(p):
paths.add(p)
returncode = 0
try:
while True:
# reset ring each run
if cat:
ring = sys.stdout
else:
ring = RingIO(lines, head)
try:
# register inotify before running the command, this avoids
# modification race conditions
if keep_open and Inotify:
inotify = Inotify(keep_open_paths)
# run the command under a pseudoterminal
mpty, spty = pty.openpty()
# forward terminal size
w, h = shutil.get_terminal_size((80, 5))
if lines:
h = lines
fcntl.ioctl(spty, termios.TIOCSWINSZ,
struct.pack('HHHH', h, w, 0, 0))
proc = sp.Popen(command,
stdout=spty,
stderr=spty,
close_fds=False)
os.close(spty)
mpty = os.fdopen(mpty, 'r', 1)
while True:
try:
line = mpty.readline()
except OSError as e:
if e.errno != errno.EIO:
raise
break
if not line:
break
if cat or not head or (head and len(ring) < h):
ring.write(line)
if not cat and not buffer and not ignore_errors:
ring.draw()
mpty.close()
proc.wait()
if ((buffer or ignore_errors or (not cat and len(ring) == 0))
and not (ignore_errors and proc.returncode != 0)):
ring.draw()
if exit_on_error and proc.returncode != 0:
returncode = proc.returncode
break
except OSError as e:
if e.errno != errno.ETXTBSY:
raise
pass
# try to inotifywait
if keep_open and Inotify:
ptime = time.time()
inotify.read()
inotify.close()
# sleep a minimum amount of time to avoid flickering
time.sleep(max(0, (sleep or 0.01) - (time.time()-ptime)))
# or sleep
else:
time.sleep(sleep or 2)
except KeyboardInterrupt:
pass
if not cat:
sys.stdout.write('\n')
sys.exit(returncode)
if __name__ == "__main__":
import sys
import argparse
parser = argparse.ArgumentParser(
description="Traditional watch command, but with higher "
"resolution updates and a bit different options/output "
"format.",
allow_abbrev=False)
parser.add_argument(
'command',
nargs=argparse.REMAINDER,
help="Command to run.")
parser.add_argument(
'-n', '--lines',
nargs='?',
type=lambda x: int(x, 0),
const=0,
help="Show this many lines of history. 0 uses the terminal "
"height. Defaults to 0.")
parser.add_argument(
'-^', '--head',
action='store_true',
help="Show the first n lines.")
parser.add_argument(
'-z', '--cat',
action='store_true',
help="Pipe directly to stdout.")
parser.add_argument(
'-s', '--sleep',
type=float,
help="Seconds to sleep between runs. Defaults to 2 seconds.")
parser.add_argument(
'-k', '--keep-open',
action='store_true',
help="Try to use inotify to wait for changes.")
parser.add_argument(
'-K', '--keep-open-path',
dest='keep_open_paths',
action='append',
help="Use this path for inotify. Defaults to guessing. Implies "
"--keep-open.")
parser.add_argument(
'-b', '--buffer',
action='store_true',
help="Wait until command finishes to show the output.")
parser.add_argument(
'-i', '--ignore-errors',
action='store_true',
help="Only show output after successful runs. Implies --buffer.")
parser.add_argument(
'-e', '--exit-on-error',
action='store_true',
help="Exit on error.")
sys.exit(main(**{k: v
for k, v in vars(parser.parse_args()).items()
if v is not None}))