prefect.utilities.annotations
¶
BaseAnnotation
¶
Base class for Prefect annotation types
Source code in prefect/utilities/annotations.py
class BaseAnnotation(ABC, Generic[T]):
"""
Base class for Prefect annotation types
"""
def __init__(self, value: T):
self.value = value
def unwrap(self) -> T:
return self.value
def __eq__(self, other: object) -> bool:
if not type(self) == type(other):
return False
return self.unwrap() == other.unwrap()
Quote
¶
Simple wrapper to mark an expression as a different type so it will not be coerced by Prefect. For example, if you want to return a state from a flow without having the flow assume that state.
Source code in prefect/utilities/annotations.py
class Quote(BaseAnnotation[T]):
"""
Simple wrapper to mark an expression as a different type so it will not be coerced
by Prefect. For example, if you want to return a state from a flow without having
the flow assume that state.
"""
def unquote(self) -> T:
return self.unwrap()
allow_failure
¶
Wrapper for states or futures.
Indicates that the upstream run for this input can be failed.
Generally, Prefect will not allow a downstream run to start if any of its inputs are failed. This annotation allows you to opt into receiving a failed input downstream.
If the input is from a failed run, the attached exception will be passed to your function.
Source code in prefect/utilities/annotations.py
class allow_failure(BaseAnnotation[T]):
"""
Wrapper for states or futures.
Indicates that the upstream run for this input can be failed.
Generally, Prefect will not allow a downstream run to start if any of its inputs
are failed. This annotation allows you to opt into receiving a failed input
downstream.
If the input is from a failed run, the attached exception will be passed to your
function.
"""
unmapped
¶
Wrapper for iterables.
Indicates that this input should be sent as-is to all runs created during a mapping operation instead of being split.
Source code in prefect/utilities/annotations.py
class unmapped(BaseAnnotation[T]):
"""
Wrapper for iterables.
Indicates that this input should be sent as-is to all runs created during a mapping
operation instead of being split.
"""
def __getitem__(self, _) -> T:
# Internally, this acts as an infinite array where all items are the same value
return self.unwrap()
quote
¶
Create a Quote object
Examples:
>>> from prefect.utilities.collections import quote
>>> x = quote(1)
>>> x.unquote()
1
Source code in prefect/utilities/annotations.py
def quote(expr: T) -> Quote[T]:
"""
Create a `Quote` object
Examples:
>>> from prefect.utilities.collections import quote
>>> x = quote(1)
>>> x.unquote()
1
"""
return Quote(expr)