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prefect.locking.protocol

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Classes

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LockManager

Methods:

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acquire_lock

acquire_lock(self, key: str, holder: str, acquire_timeout: Optional[float] = None, hold_timeout: Optional[float] = None) -> bool

Acquire a lock for a transaction record with the given key. Will block other actors from updating this transaction record until the lock is released.

Args:

• key: Unique identifier for the transaction record.
• holder: Unique identifier for the holder of the lock.
• acquire_timeout: Max number of seconds to wait for the record to become available if it is locked while attempting to acquire a lock. Pass 0 to attempt to acquire a lock without waiting. Blocks indefinitely by default.
• hold_timeout: Max number of seconds to hold the lock for. Holds the lock indefinitely by default.

Returns:

• True if the lock was successfully acquired; False otherwise.

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release_lock

release_lock(self, key: str, holder: str) -> None

Releases the lock on the corresponding transaction record.

Args:

• key: Unique identifier for the transaction record.
• holder: Unique identifier for the holder of the lock. Must match the holder provided when acquiring the lock.

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is_locked

is_locked(self, key: str) -> bool

Simple check to see if the corresponding record is currently locked.

Args:

• key: Unique identifier for the transaction record.

Returns:

• True is the record is locked; False otherwise.

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is_lock_holder

is_lock_holder(self, key: str, holder: str) -> bool

Check if the current holder is the lock holder for the transaction record.

Args:

• key: Unique identifier for the transaction record.
• holder: Unique identifier for the holder of the lock.

Returns:

• True if the current holder is the lock holder; False otherwise.

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wait_for_lock

wait_for_lock(self, key: str, timeout: Optional[float] = None) -> bool

Wait for the corresponding transaction record to become free.

Args:

• key: Unique identifier for the transaction record.
• timeout: Maximum time to wait. None means to wait indefinitely.

Returns:

• True if the lock becomes free within the timeout; False otherwise.