Roland Thomas
7f63e16097
- Add comprehensive module docstrings across the codebase for better clarity and documentation. - Refactor Enum classes (e.g., FileType, ConfirmType) to use `_missing_` for built-in coercion from strings. - Add `encoding` attribute to `LoadFileAction`, `SaveFileAction`, and `SelectFileAction` for more flexible file handling. - Enable lazy file loading by default in `SelectFileAction` to improve performance. - Simplify bottom bar toggle behavior: all toggles now use `ctrl+<key>`, eliminating the need for key conflict checks with Falyx commands. - Add `ignore_in_history` attribute to `Command` to refine how `ExecutionRegistry` identifies the last valid result. - Improve History command output: now includes tracebacks when displaying exceptions.
88 lines
3.0 KiB
Python
88 lines
3.0 KiB
Python
# Falyx CLI Framework — (c) 2025 rtj.dev LLC — MIT Licensed
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"""
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Defines `FallbackAction`, a lightweight recovery Action used within `ChainedAction`
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pipelines to gracefully handle errors or missing results from a preceding step.
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When placed immediately after a failing or null-returning Action, `FallbackAction`
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injects the `last_result` and checks whether it is `None`. If so, it substitutes a
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predefined fallback value and allows the chain to continue. If `last_result` is valid,
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it is passed through unchanged.
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This mechanism allows workflows to recover from failure or gaps in data
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without prematurely terminating the entire chain.
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Key Features:
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- Injects and inspects `last_result`
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- Replaces `None` with a fallback value
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- Consumes upstream errors when used with `ChainedAction`
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- Fully compatible with Falyx's preview and hook systems
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Typical Use Cases:
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- Graceful degradation in chained workflows
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- Providing default values when earlier steps are optional
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- Replacing missing data with static or precomputed values
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Example:
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ChainedAction(
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name="FetchWithFallback",
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actions=[
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Action("MaybeFetchRemoteAction", action=fetch_data),
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FallbackAction(fallback={"data": "default"}),
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Action("ProcessDataAction", action=process_data),
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],
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auto_inject=True,
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)
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The `FallbackAction` ensures that even if `MaybeFetchRemoteAction` fails or returns
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None, `ProcessDataAction` still receives a usable input.
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"""
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from functools import cached_property
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from typing import Any
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from rich.tree import Tree
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from falyx.action.action import Action
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from falyx.themes import OneColors
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class FallbackAction(Action):
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"""
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FallbackAction provides a default value if the previous action failed or
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returned None.
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It injects the last result and checks:
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- If last_result is not None, it passes it through unchanged.
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- If last_result is None (e.g., due to failure), it replaces it with a fallback value.
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Used in ChainedAction pipelines to gracefully recover from errors or missing data.
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When activated, it consumes the preceding error and allows the chain to continue
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normally.
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Args:
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fallback (Any): The fallback value to use if last_result is None.
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"""
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def __init__(self, fallback: Any):
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self._fallback = fallback
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async def _fallback_logic(last_result):
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return last_result if last_result is not None else fallback
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super().__init__(name="Fallback", action=_fallback_logic, inject_last_result=True)
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@cached_property
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def fallback(self) -> Any:
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"""Return the fallback value."""
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return self._fallback
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async def preview(self, parent: Tree | None = None):
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label = [f"[{OneColors.LIGHT_RED}]🛟 Fallback[/] '{self.name}'"]
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label.append(f" [dim](uses fallback = {repr(self.fallback)})[/dim]")
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if parent:
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parent.add("".join(label))
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else:
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self.console.print(Tree("".join(label)))
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def __str__(self) -> str:
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return f"FallbackAction(fallback={self.fallback!r})"
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