130 lines
5.3 KiB
Python
130 lines
5.3 KiB
Python
# Copyright (c) Microsoft. All rights reserved.
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import importlib
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import inspect
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from collections.abc import Sequence
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from typing import Any
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from semantic_kernel.exceptions.process_exceptions import ProcessInvalidConfigurationException
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from semantic_kernel.functions.kernel_function import KernelFunction
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from semantic_kernel.processes.kernel_process.kernel_process_message_channel import KernelProcessMessageChannel
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from semantic_kernel.processes.kernel_process.kernel_process_step import KernelProcessStep
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from semantic_kernel.processes.kernel_process.kernel_process_step_context import KernelProcessStepContext
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from semantic_kernel.utils.feature_stage_decorator import experimental
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DEFAULT_ALLOWED_MODULE_PREFIXES: tuple[str, ...] = ("semantic_kernel.",)
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@experimental
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def find_input_channels(
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channel: KernelProcessMessageChannel, functions: dict[str, KernelFunction]
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) -> dict[str, dict[str, Any | None]]:
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"""Finds and creates input channels."""
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if not functions:
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raise ValueError("The step has not been initialized.")
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inputs: dict[str, Any] = {}
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for name, function in functions.items():
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inputs[name] = {}
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for param in function.metadata.parameters:
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# Check for Kernel, and skip if necessary, since it is populated later on
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if param.type_ == "Kernel":
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continue
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if not param.is_required:
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continue
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if param.type_ == "KernelProcessStepContext":
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inputs[name][param.name] = KernelProcessStepContext(channel)
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else:
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inputs[name][param.name] = None
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return inputs
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@experimental
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def get_fully_qualified_name(cls) -> str:
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"""Gets the fully qualified name of a class."""
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return f"{cls.__module__}.{cls.__name__}"
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@experimental
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def get_step_class_from_qualified_name(
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full_class_name: str,
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allowed_module_prefixes: Sequence[str] | None = DEFAULT_ALLOWED_MODULE_PREFIXES,
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) -> type[KernelProcessStep]:
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"""Loads and validates a KernelProcessStep class from a fully qualified name.
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This function validates that the loaded class is a proper subclass of
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KernelProcessStep, preventing instantiation of arbitrary classes.
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Args:
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full_class_name: The fully qualified class name in Python import notation
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(e.g., 'mypackage.mymodule.MyStep'). The module must be importable
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from the current Python environment.
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allowed_module_prefixes: Sequence of module prefixes that are allowed
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to be imported. The module must start with one of these prefixes.
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This check is performed BEFORE import to prevent execution of
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module-level code in unauthorized modules. Defaults to
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("semantic_kernel.",). Pass None to allow any module (not
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recommended for production). An empty sequence blocks all modules.
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Returns:
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The validated class type that is a subclass of KernelProcessStep
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Raises:
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ProcessInvalidConfigurationException: Raised when:
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- The class name format is invalid (missing module separator)
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- The module is not in the allowed prefixes list (if provided)
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- The module cannot be imported
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- The class attribute doesn't exist in the module
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- The attribute is not a class type
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- The class is not a subclass of KernelProcessStep
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"""
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if not full_class_name or "." not in full_class_name:
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raise ProcessInvalidConfigurationException(
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f"Invalid step class name format: '{full_class_name}'. "
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"Expected a fully qualified name like 'module.ClassName'."
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)
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module_name, class_name = full_class_name.rsplit(".", 1)
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if not module_name or not class_name:
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raise ProcessInvalidConfigurationException(
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f"Invalid step class name format: '{full_class_name}'. Module name and class name cannot be empty."
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)
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# Check module allowlist BEFORE import to prevent module-level code execution
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if allowed_module_prefixes is not None and not any(
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module_name.startswith(prefix)
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if prefix.endswith(".")
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else (module_name == prefix or module_name.startswith(prefix + "."))
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for prefix in allowed_module_prefixes
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):
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raise ProcessInvalidConfigurationException(
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f"Module '{module_name}' is not in the allowed module prefixes: {allowed_module_prefixes}. "
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f"Step class '{full_class_name}' cannot be loaded."
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)
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try:
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module = importlib.import_module(module_name)
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except ImportError as e:
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raise ProcessInvalidConfigurationException(
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f"Unable to import module '{module_name}' for step class '{full_class_name}': {e}"
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) from e
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try:
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cls = getattr(module, class_name)
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except AttributeError as e:
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raise ProcessInvalidConfigurationException(
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f"Class '{class_name}' not found in module '{module_name}': {e}"
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) from e
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if not inspect.isclass(cls):
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raise ProcessInvalidConfigurationException(f"'{full_class_name}' is not a class type, got {type(cls).__name__}")
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if not issubclass(cls, KernelProcessStep):
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raise ProcessInvalidConfigurationException(
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f"Step class '{full_class_name}' must be a subclass of KernelProcessStep. Got: {cls.__bases__}"
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)
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return cls
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