ArchiveBox/archivebox/system.py
2019-04-30 23:13:04 -04:00

150 lines
4.8 KiB
Python

__package__ = 'archivebox'
import os
import shutil
import json as pyjson
from typing import Optional, Union, Set, Tuple
from crontab import CronTab
from subprocess import (
Popen,
PIPE,
DEVNULL,
CompletedProcess,
TimeoutExpired,
CalledProcessError,
)
from .util import enforce_types, ExtendedEncoder
from .config import OUTPUT_PERMISSIONS
def run(*popenargs, input=None, capture_output=False, timeout=None, check=False, **kwargs):
"""Patched of subprocess.run to fix blocking io making timeout=innefective"""
if input is not None:
if 'stdin' in kwargs:
raise ValueError('stdin and input arguments may not both be used.')
kwargs['stdin'] = PIPE
if capture_output:
if ('stdout' in kwargs) or ('stderr' in kwargs):
raise ValueError('stdout and stderr arguments may not be used '
'with capture_output.')
kwargs['stdout'] = PIPE
kwargs['stderr'] = PIPE
with Popen(*popenargs, **kwargs) as process:
try:
stdout, stderr = process.communicate(input, timeout=timeout)
except TimeoutExpired:
process.kill()
try:
stdout, stderr = process.communicate(input, timeout=2)
except:
pass
raise TimeoutExpired(popenargs[0][0], timeout)
except BaseException:
process.kill()
# We don't call process.wait() as .__exit__ does that for us.
raise
retcode = process.poll()
if check and retcode:
raise CalledProcessError(retcode, process.args,
output=stdout, stderr=stderr)
return CompletedProcess(process.args, retcode, stdout, stderr)
def atomic_write(contents: Union[dict, str, bytes], path: str) -> None:
"""Safe atomic write to filesystem by writing to temp file + atomic rename"""
try:
tmp_file = '{}.tmp'.format(path)
if isinstance(contents, bytes):
args = {'mode': 'wb+'}
else:
args = {'mode': 'w+', 'encoding': 'utf-8'}
with open(tmp_file, **args) as f:
if isinstance(contents, dict):
pyjson.dump(contents, f, indent=4, sort_keys=True, cls=ExtendedEncoder)
else:
f.write(contents)
os.fsync(f.fileno())
os.rename(tmp_file, path)
chmod_file(path)
finally:
if os.path.exists(tmp_file):
os.remove(tmp_file)
@enforce_types
def chmod_file(path: str, cwd: str='.', permissions: str=OUTPUT_PERMISSIONS, timeout: int=30) -> None:
"""chmod -R <permissions> <cwd>/<path>"""
if not os.path.exists(os.path.join(cwd, path)):
raise Exception('Failed to chmod: {} does not exist (did the previous step fail?)'.format(path))
chmod_result = run(['chmod', '-R', permissions, path], cwd=cwd, stdout=DEVNULL, stderr=PIPE, timeout=timeout)
if chmod_result.returncode == 1:
print(' ', chmod_result.stderr.decode())
raise Exception('Failed to chmod {}/{}'.format(cwd, path))
@enforce_types
def copy_and_overwrite(from_path: str, to_path: str):
"""copy a given file or directory to a given path, overwriting the destination"""
if os.path.isdir(from_path):
shutil.rmtree(to_path, ignore_errors=True)
shutil.copytree(from_path, to_path)
else:
with open(from_path, 'rb') as src:
atomic_write(src.read(), to_path)
@enforce_types
def get_dir_size(path: str, recursive: bool=True, pattern: Optional[str]=None) -> Tuple[int, int, int]:
"""get the total disk size of a given directory, optionally summing up
recursively and limiting to a given filter list
"""
num_bytes, num_dirs, num_files = 0, 0, 0
for entry in os.scandir(path):
if (pattern is not None) and (pattern not in entry.path):
continue
if entry.is_dir(follow_symlinks=False):
if not recursive:
continue
num_dirs += 1
bytes_inside, dirs_inside, files_inside = get_dir_size(entry.path)
num_bytes += bytes_inside
num_dirs += dirs_inside
num_files += files_inside
else:
num_bytes += entry.stat(follow_symlinks=False).st_size
num_files += 1
return num_bytes, num_dirs, num_files
CRON_COMMENT = 'archivebox_schedule'
@enforce_types
def dedupe_cron_jobs(cron: CronTab) -> CronTab:
deduped: Set[Tuple[str, str]] = set()
for job in list(cron):
unique_tuple = (str(job.slices), job.command)
if unique_tuple not in deduped:
deduped.add(unique_tuple)
cron.remove(job)
for schedule, command in deduped:
job = cron.new(command=command, comment=CRON_COMMENT)
job.setall(schedule)
job.enable()
return cron