prefect.utilities.callables
¶
Utilities for working with Python callables.
ParameterSchema
¶
Bases: BaseModel
Simple data model corresponding to an OpenAPI Schema
.
Source code in prefect/utilities/callables.py
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dict
¶
Exclude None
fields by default to comply with
the OpenAPI spec.
Source code in prefect/utilities/callables.py
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call_with_parameters
¶
Call a function with parameters extracted with get_call_parameters
The function must have an identical signature to the original function or this
will fail. If you need to send to a function with a different signature, extract
the args/kwargs using parameters_to_positional_and_keyword
directly
Source code in prefect/utilities/callables.py
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cloudpickle_wrapped_call
¶
Serializes a function call using cloudpickle then returns a callable which will execute that call and return a cloudpickle serialized return value
This is particularly useful for sending calls to libraries that only use the Python
built-in pickler (e.g. anyio.to_process
and multiprocessing
) but may require
a wider range of pickling support.
Source code in prefect/utilities/callables.py
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collapse_variadic_parameters
¶
Given a parameter dictionary, move any parameters stored not present in the signature into the variadic keyword argument.
Example:
```python
def foo(a, b, **kwargs):
pass
parameters = {"a": 1, "b": 2, "c": 3, "d": 4}
collapse_variadic_parameters(foo, parameters)
# {"a": 1, "b": 2, "kwargs": {"c": 3, "d": 4}}
```
Source code in prefect/utilities/callables.py
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explode_variadic_parameter
¶
Given a parameter dictionary, move any parameters stored in a variadic keyword argument parameter (i.e. **kwargs) into the top level.
Example:
```python
def foo(a, b, **kwargs):
pass
parameters = {"a": 1, "b": 2, "kwargs": {"c": 3, "d": 4}}
explode_variadic_parameter(foo, parameters)
# {"a": 1, "b": 2, "c": 3, "d": 4}
```
Source code in prefect/utilities/callables.py
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generate_parameter_schema
¶
Generate a parameter schema from a function signature and docstrings.
To get a signature from a function, use inspect.signature(fn)
or
_generate_signature_from_source(source_code, func_name)
.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
signature |
Signature
|
The function signature. |
required |
docstrings |
Dict[str, str]
|
A dictionary mapping parameter names to docstrings. |
required |
Returns:
Name | Type | Description |
---|---|---|
ParameterSchema |
ParameterSchema
|
The parameter schema. |
Source code in prefect/utilities/callables.py
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get_call_parameters
¶
Bind a call to a function to get parameter/value mapping. Default values on the signature will be included if not overridden.
Raises a ParameterBindError if the arguments/kwargs are not valid for the function
Source code in prefect/utilities/callables.py
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get_parameter_defaults
¶
Get default parameter values for a callable.
Source code in prefect/utilities/callables.py
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parameter_docstrings
¶
Given a docstring in Google docstring format, parse the parameter section and return a dictionary that maps parameter names to docstring.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
docstring |
Optional[str]
|
The function's docstring. |
required |
Returns:
Type | Description |
---|---|
Dict[str, str]
|
Mapping from parameter names to docstrings. |
Source code in prefect/utilities/callables.py
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parameter_schema
¶
Given a function, generates an OpenAPI-compatible description of the function's arguments, including: - name - typing information - whether it is required - a default value - additional constraints (like possible enum values)
Parameters:
Name | Type | Description | Default |
---|---|---|---|
fn |
Callable
|
The function whose arguments will be serialized |
required |
Returns:
Name | Type | Description |
---|---|---|
ParameterSchema |
ParameterSchema
|
the argument schema |
Source code in prefect/utilities/callables.py
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parameter_schema_from_entrypoint
¶
Generate a parameter schema from an entrypoint string.
Will load the source code of the function and extract the signature and docstring to generate the schema.
Useful for generating a schema for a function when instantiating the function may not be possible due to missing imports or other issues.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
entrypoint |
str
|
A string representing the entrypoint to a function. The string
should be in the format of |
required |
Returns:
Name | Type | Description |
---|---|---|
ParameterSchema |
ParameterSchema
|
The parameter schema for the function. |
Source code in prefect/utilities/callables.py
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parameters_to_args_kwargs
¶
Convert a parameters
dictionary to positional and keyword arguments
The function must have an identical signature to the original function or this will return an empty tuple and dict.
Source code in prefect/utilities/callables.py
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raise_for_reserved_arguments
¶
Raise a ReservedArgumentError if fn
has any parameters that conflict
with the names contained in reserved_arguments
.
Source code in prefect/utilities/callables.py
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