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213 | @deprecated.deprecated_class(
start_date="Sep 2024",
end_date="Nov 2024",
help="Use `ResultStore` with a `LocalFileSystem` for `metadata_storage` and a `FileSystemLockManager` instead.",
)
class FileSystemRecordStore(RecordStore):
"""
A record store that stores data on the local filesystem.
Locking is implemented using a lock file with the same name as the record file,
but with a `.lock` extension.
Attributes:
records_directory: the directory where records are stored; defaults to
`{PREFECT_HOME}/records`
"""
def __init__(self, records_directory: Path):
self.records_directory = records_directory
self._locks: Dict[str, _LockInfo] = {}
def _ensure_records_directory_exists(self):
self.records_directory.mkdir(parents=True, exist_ok=True)
def _lock_path_for_key(self, key: str) -> Path:
if (lock_info := self._locks.get(key)) is not None:
return lock_info["path"]
return self.records_directory.joinpath(key).with_suffix(".lock")
def _get_lock_info(self, key: str, use_cache=True) -> Optional[_LockInfo]:
if use_cache:
if (lock_info := self._locks.get(key)) is not None:
return lock_info
lock_path = self._lock_path_for_key(key)
try:
with open(lock_path, "r") as lock_file:
lock_info = json.load(lock_file)
lock_info["path"] = lock_path
expiration = lock_info.get("expiration")
lock_info["expiration"] = (
pendulum.parse(expiration) if expiration is not None else None
)
self._locks[key] = lock_info
return lock_info
except FileNotFoundError:
return None
def read(
self, key: str, holder: Optional[str] = None, timeout: Optional[float] = None
) -> Optional[TransactionRecord]:
if not self.exists(key):
return None
holder = holder or self.generate_default_holder()
if self.is_locked(key) and not self.is_lock_holder(key, holder):
unlocked = self.wait_for_lock(key, timeout=timeout)
if not unlocked:
return None
record_data = self.records_directory.joinpath(key).read_text()
return TransactionRecord(
key=key, result=BaseResult.model_validate_json(record_data)
)
def write(self, key: str, result: BaseResult, holder: Optional[str] = None) -> None:
self._ensure_records_directory_exists()
if self.is_locked(key) and not self.is_lock_holder(key, holder):
raise ValueError(
f"Cannot write to transaction with key {key} because it is locked by another holder."
)
record_path = self.records_directory.joinpath(key)
record_path.touch(exist_ok=True)
record_data = result.model_dump_json()
record_path.write_text(record_data)
def exists(self, key: str) -> bool:
return self.records_directory.joinpath(key).exists()
def supports_isolation_level(self, isolation_level: IsolationLevel) -> bool:
return isolation_level in {
IsolationLevel.READ_COMMITTED,
IsolationLevel.SERIALIZABLE,
}
def acquire_lock(
self,
key: str,
holder: Optional[str] = None,
acquire_timeout: Optional[float] = None,
hold_timeout: Optional[float] = None,
) -> bool:
holder = holder or self.generate_default_holder()
self._ensure_records_directory_exists()
lock_path = self._lock_path_for_key(key)
if self.is_locked(key) and not self.is_lock_holder(key, holder):
lock_free = self.wait_for_lock(key, acquire_timeout)
if not lock_free:
return False
try:
Path(lock_path).touch(exist_ok=False)
except FileExistsError:
if not self.is_lock_holder(key, holder):
logger.debug(
f"Another actor acquired the lock for record with key {key}. Trying again."
)
return self.acquire_lock(key, holder, acquire_timeout, hold_timeout)
expiration = (
pendulum.now("utc") + pendulum.duration(seconds=hold_timeout)
if hold_timeout is not None
else None
)
with open(Path(lock_path), "w") as lock_file:
json.dump(
{
"holder": holder,
"expiration": str(expiration) if expiration is not None else None,
},
lock_file,
)
self._locks[key] = {
"holder": holder,
"expiration": expiration,
"path": lock_path,
}
return True
def release_lock(self, key: str, holder: Optional[str] = None) -> None:
holder = holder or self.generate_default_holder()
lock_path = self._lock_path_for_key(key)
if not self.is_locked(key):
ValueError(f"No lock for transaction with key {key}")
if self.is_lock_holder(key, holder):
Path(lock_path).unlink(missing_ok=True)
self._locks.pop(key, None)
else:
raise ValueError(f"No lock held by {holder} for transaction with key {key}")
def is_locked(self, key: str, use_cache: bool = False) -> bool:
if (lock_info := self._get_lock_info(key, use_cache=use_cache)) is None:
return False
if (expiration := lock_info.get("expiration")) is None:
return True
expired = expiration < pendulum.now("utc")
if expired:
Path(lock_info["path"]).unlink()
self._locks.pop(key, None)
return False
else:
return True
def is_lock_holder(self, key: str, holder: Optional[str] = None) -> bool:
if not self.is_locked(key):
return False
holder = holder or self.generate_default_holder()
if not self.is_locked(key):
return False
if (lock_info := self._get_lock_info(key)) is None:
return False
return lock_info["holder"] == holder
def wait_for_lock(self, key: str, timeout: Optional[float] = None) -> bool:
seconds_waited = 0
while self.is_locked(key, use_cache=False):
if timeout and seconds_waited >= timeout:
return False
seconds_waited += 0.1
time.sleep(0.1)
return True
|