45 lines
963 B
Python
45 lines
963 B
Python
|
import contextlib
|
||
|
|
import json
|
||
|
|
import pathlib
|
||
|
|
import time
|
||
|
|
|
||
|
|
def lock(name):
|
||
|
|
lockfile = pathlib.Path(f'{name}.lock')
|
||
|
|
for i in range(5):
|
||
|
|
try:
|
||
|
|
lockfile.symlink_to('/dev/null')
|
||
|
|
return
|
||
|
|
except FileExistsError:
|
||
|
|
time.sleep(1)
|
||
|
|
raise TimeoutError(f'could not lock {name}')
|
||
|
|
|
||
|
|
def unlock(name):
|
||
|
|
lockfile = pathlib.Path(f'{name}.lock')
|
||
|
|
lockfile.unlink(missing_ok=True)
|
||
|
|
|
||
|
|
@contextlib.contextmanager
|
||
|
|
def locked(name):
|
||
|
|
lock(name)
|
||
|
|
try:
|
||
|
|
yield name
|
||
|
|
finally:
|
||
|
|
unlock(name)
|
||
|
|
|
||
|
|
def read(name):
|
||
|
|
with open(f'{name}.json', 'a+', encoding='utf-8') as f:
|
||
|
|
f.seek(0)
|
||
|
|
return json.loads(f.read() or '{}')
|
||
|
|
|
||
|
|
def write(name, data):
|
||
|
|
with open(f'{name}.json', 'w', encoding='utf-8') as f:
|
||
|
|
json.dump(data, f, indent=2)
|
||
|
|
f.close()
|
||
|
|
|
||
|
|
def load(name):
|
||
|
|
with locked(name):
|
||
|
|
return read(name)
|
||
|
|
|
||
|
|
def save(name, data):
|
||
|
|
with locked(name):
|
||
|
|
write(name, data)
|