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prefect.transactions

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Functions

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get_transaction

get_transaction() -> BaseTransaction | None

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transaction

transaction(key: str | None = None, store: ResultStore | None = None, commit_mode: CommitMode | None = None, isolation_level: IsolationLevel | None = None, overwrite: bool = False, write_on_commit: bool = True, logger: logging.Logger | LoggingAdapter | None = None) -> Generator[Transaction, None, None]

A context manager for opening and managing a transaction.

Args:

• -: An identifier to use for the transaction
• -: The store to use for persisting the transaction result. If not provided, a default store will be used based on the current run context.
• -: The commit mode controlling when the transaction and child transactions are committed
• -: Whether to overwrite an existing transaction record in the store
• -: Whether to write the result to the store on commit. If not provided, will default will be determined by the current run context. If no run context is available, the value of PREFECT_RESULTS_PERSIST_BY_DEFAULT will be used.

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Classes

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IsolationLevel

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CommitMode

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TransactionState

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BaseTransaction

A base model for transaction state.

Methods:

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set

set(self, name: str, value: Any) -> None

Set a stored value in the transaction.

Args:

• name: The name of the value to set
• value: The value to set

Examples:

Set a value for use later in the transaction:

with transaction() as txn:
    txn.set("key", "value")
    ...
    assert txn.get("key") == "value"

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get

get(self, name: str, default: Any = NotSet) -> Any

Get a stored value from the transaction.

Child transactions will return values from their parents unless a value with the same name is set in the child transaction.

Direct changes to returned values will not update the stored value. To update the stored value, use the set method.

Args:

• name: The name of the value to get
• default: The default value to return if the value is not found

Returns:

• The value from the transaction

Examples:

Get a value from the transaction:

with transaction() as txn:
    txn.set("key", "value")
    ...
    assert txn.get("key") == "value"

Get a value from a parent transaction:

with transaction() as parent:
    parent.set("key", "parent_value")
    with transaction() as child:
        assert child.get("key") == "parent_value"

Update a stored value:

with transaction() as txn:
    txn.set("key", [1, 2, 3])
    value = txn.get("key")
    value.append(4)
    # Stored value is not updated until `.set` is called
    assert value == [1, 2, 3, 4]
    assert txn.get("key") == [1, 2, 3]

    txn.set("key", value)
    assert txn.get("key") == [1, 2, 3, 4]

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is_committed

is_committed(self) -> bool

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is_rolled_back

is_rolled_back(self) -> bool

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is_staged

is_staged(self) -> bool

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is_pending

is_pending(self) -> bool

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is_active

is_active(self) -> bool

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prepare_transaction

prepare_transaction(self) -> None

Helper method to prepare transaction state and validate configuration.

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add_child

add_child(self, transaction: Self) -> None

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get_parent

get_parent(self) -> Self | None

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stage

stage(self, value: Any, on_rollback_hooks: Optional[list[Callable[..., Any]]] = None, on_commit_hooks: Optional[list[Callable[..., Any]]] = None) -> None

Stage a value to be committed later.

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get_active

get_active(cls: Type[Self]) -> Optional[Self]

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Transaction

A model representing the state of a transaction.

Methods:

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begin

begin(self) -> None

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read

read(self) -> ResultRecord[Any] | None

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reset

reset(self) -> None

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commit

commit(self) -> bool

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run_hook

run_hook(self, hook: Callable[..., Any], hook_type: str) -> None

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rollback

rollback(self) -> bool

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AsyncTransaction

A model representing the state of an asynchronous transaction.