prefect.utilities.importtools
¶
AliasedModuleDefinition
¶
Bases: NamedTuple
A definition for the AliasedModuleFinder
.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
alias |
The import name to create |
required | |
real |
The import name of the module to reference for the alias |
required | |
callback |
A function to call when the alias module is loaded |
required |
Source code in prefect/utilities/importtools.py
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AliasedModuleFinder
¶
Bases: MetaPathFinder
Source code in prefect/utilities/importtools.py
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find_spec
¶
The fullname is the imported path, e.g. "foo.bar". If there is an alias "phi" for "foo" then on import of "phi.bar" we will find the spec for "foo.bar" and create a new spec for "phi.bar" that points to "foo.bar".
Source code in prefect/utilities/importtools.py
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DelayedImportErrorModule
¶
Bases: ModuleType
A fake module returned by lazy_import
when the module cannot be found. When any
of the module's attributes are accessed, we will throw a ModuleNotFoundError
.
Adapted from lazy_loader
Source code in prefect/utilities/importtools.py
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from_qualified_name
¶
Import an object given a fully-qualified name.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
name |
str
|
The fully-qualified name of the object to import. |
required |
Returns:
Type | Description |
---|---|
Any
|
the imported object |
Examples:
>>> obj = from_qualified_name("random.randint")
>>> import random
>>> obj == random.randint
True
Source code in prefect/utilities/importtools.py
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import_object
¶
Load an object from an import path.
Import paths can be formatted as one of: - module.object - module:object - /path/to/script.py:object
This function is not thread safe as it modifies the 'sys' module during execution.
Source code in prefect/utilities/importtools.py
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lazy_import
¶
Create a lazily-imported module to use in place of the module of the given name. Use this to retain module-level imports for libraries that we don't want to actually import until they are needed.
Adapted from the Python documentation and lazy_loader
Source code in prefect/utilities/importtools.py
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load_module
¶
Import a module with support for relative imports within the module.
Source code in prefect/utilities/importtools.py
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load_script_as_module
¶
Execute a script at the given path.
Sets the module name to __prefect_loader__
.
If an exception occurs during execution of the script, a
prefect.exceptions.ScriptError
is created to wrap the exception and raised.
During the duration of this function call, sys
is modified to support loading.
These changes are reverted after completion, but this function is not thread safe
and use of it in threaded contexts may result in undesirable behavior.
See https://docs.python.org/3/library/importlib.html#importing-a-source-file-directly
Source code in prefect/utilities/importtools.py
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objects_from_script
¶
Run a python script and return all the global variables
Supports remote paths by copying to a local temporary file.
WARNING: The Python documentation does not recommend using runpy for this pattern.
Furthermore, any functions and classes defined by the executed code are not guaranteed to work correctly after a runpy function has returned. If that limitation is not acceptable for a given use case, importlib is likely to be a more suitable choice than this module.
The function load_script_as_module
uses importlib instead and should be used
instead for loading objects from scripts.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
path |
str
|
The path to the script to run |
required |
text |
Union[str, bytes]
|
Optionally, the text of the script. Skips loading the contents if given. |
None
|
Returns:
Type | Description |
---|---|
Dict[str, Any]
|
A dictionary mapping variable name to value |
Raises:
Type | Description |
---|---|
ScriptError
|
if the script raises an exception during execution |
Source code in prefect/utilities/importtools.py
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safe_load_namespace
¶
Safely load a namespace from source code, optionally handling relative imports.
If a filepath
is provided, sys.path
is modified to support relative imports.
Changes to sys.path
are reverted after completion, but this function is not thread safe
and use of it in threaded contexts may result in undesirable behavior.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
source_code |
str
|
The source code to load |
required |
filepath |
Optional[str]
|
Optional file path of the source code. If provided, enables relative imports. |
None
|
Returns:
Type | Description |
---|---|
Dict[str, Any]
|
The namespace loaded from the source code. |
Source code in prefect/utilities/importtools.py
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to_qualified_name
¶
Given an object, returns its fully-qualified name: a string that represents its Python import path.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
obj |
Any
|
an importable Python object |
required |
Returns:
Name | Type | Description |
---|---|---|
str |
str
|
the qualified name |
Source code in prefect/utilities/importtools.py
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