prefect.records.base
RecordStore
Bases: ABC
Source code in src/prefect/records/base.py
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acquire_lock(key, holder=None, acquire_timeout=None, hold_timeout=None)
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.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
key |
str
|
Unique identifier for the transaction record. |
required |
holder |
Optional[str]
|
Unique identifier for the holder of the lock. If not provided, a default holder based on the current host, process, and thread will be used. |
None
|
acquire_timeout |
Optional[float]
|
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. |
None
|
hold_timeout |
Optional[float]
|
Max number of seconds to hold the lock for. Holds the lock indefinitely by default. |
None
|
Returns:
Name | Type | Description |
---|---|---|
bool |
bool
|
True if the lock was successfully acquired; False otherwise. |
Source code in src/prefect/records/base.py
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exists(key)
abstractmethod
Check if the transaction record with the given key exists.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
key |
str
|
Unique identifier for the transaction record. |
required |
Returns:
Name | Type | Description |
---|---|---|
bool |
bool
|
True if the record exists; False otherwise. |
Source code in src/prefect/records/base.py
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generate_default_holder()
staticmethod
Generate a default holder string using hostname, PID, and thread ID.
Returns:
Name | Type | Description |
---|---|---|
str |
str
|
A unique identifier string. |
Source code in src/prefect/records/base.py
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is_lock_holder(key, holder=None)
Check if the current holder is the lock holder for the transaction record.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
key |
str
|
Unique identifier for the transaction record. |
required |
holder |
Optional[str]
|
Unique identifier for the holder of the lock. If not provided, a default holder based on the current host, process, and thread will be used. |
None
|
Returns:
Name | Type | Description |
---|---|---|
bool |
bool
|
True if the current holder is the lock holder; False otherwise. |
Source code in src/prefect/records/base.py
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is_locked(key)
Simple check to see if the corresponding record is currently locked.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
key |
str
|
Unique identifier for the transaction record. |
required |
Returns:
Type | Description |
---|---|
bool
|
True is the record is locked; False otherwise. |
Source code in src/prefect/records/base.py
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lock(key, holder=None, acquire_timeout=None, hold_timeout=None)
Context manager to lock the transaction record during the execution of the nested code block.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
key |
str
|
Unique identifier for the transaction record. |
required |
holder |
Optional[str]
|
Unique identifier for the holder of the lock. If not provided, a default holder based on the current host, process, and thread will be used. |
None
|
acquire_timeout |
Optional[float]
|
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. |
None
|
hold_timeout |
Optional[float]
|
Max number of seconds to hold the lock for. Holds the lock indefinitely by default. |
None
|
Example
Hold a lock while during an operation:
python
with TransactionRecord(key="my-transaction-record-key").lock():
do_stuff()
Source code in src/prefect/records/base.py
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read(key, holder=None)
abstractmethod
Read the transaction record with the given key.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
key |
str
|
Unique identifier for the transaction record. |
required |
holder |
Optional[str]
|
Unique identifier for the holder of the lock. If a lock exists on the record being written, the read will be blocked until the lock is released if the provided holder does not match the holder of the lock. If not provided, a default holder based on the current host, process, and thread will be used. |
None
|
Returns:
Name | Type | Description |
---|---|---|
TransactionRecord |
Optional[TransactionRecord]
|
The transaction record with the given key. |
Source code in src/prefect/records/base.py
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release_lock(key, holder=None)
Releases the lock on the corresponding transaction record.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
key |
str
|
Unique identifier for the transaction record. |
required |
holder |
Optional[str]
|
Unique identifier for the holder of the lock. Must match the holder provided when acquiring the lock. |
None
|
Source code in src/prefect/records/base.py
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supports_isolation_level(isolation_level)
abstractmethod
Check if the record store supports the given isolation level.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
isolation_level |
IsolationLevel
|
The isolation level to check. |
required |
Returns:
Name | Type | Description |
---|---|---|
bool |
bool
|
True if the record store supports the isolation level; False otherwise. |
Source code in src/prefect/records/base.py
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wait_for_lock(key, timeout=None)
Wait for the corresponding transaction record to become free.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
key |
str
|
Unique identifier for the transaction record. |
required |
timeout |
Optional[float]
|
Maximum time to wait. None means to wait indefinitely. |
None
|
Returns:
Name | Type | Description |
---|---|---|
bool |
bool
|
True if the lock becomes free within the timeout; False otherwise. |
Source code in src/prefect/records/base.py
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write(key, result, holder=None)
abstractmethod
Write the transaction record with the given key.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
key |
str
|
Unique identifier for the transaction record. |
required |
record |
The transaction record to write. |
required | |
holder |
Optional[str]
|
Unique identifier for the holder of the lock. If a lock exists on the record being written, the write will be rejected if the provided holder does not match the holder of the lock. If not provided, a default holder based on the current host, process, and thread will be used. |
None
|
Source code in src/prefect/records/base.py
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TransactionRecord
dataclass
A dataclass representation of a transaction record.
Source code in src/prefect/records/base.py
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