225 lines
8.4 KiB
Python
225 lines
8.4 KiB
Python
import asyncio
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# ---------------------------------------------------------------------
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# Base Classes
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# ---------------------------------------------------------------------
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class BaseNode:
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def __init__(self):
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self.set_parameters({})
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self.successors = {}
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def set_parameters(self, parameters):
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self.parameters = parameters.copy() if parameters else {}
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def add_successor(self, node, condition="default"):
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self.successors[condition] = node
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return node
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async def preprocess(self, shared_storage):
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return None
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async def process_one(self, shared_storage, item):
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"""
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The main single-item processing method that end developers override.
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Default does nothing.
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"""
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return None
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async def robust_process_one(self, shared_storage, item):
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"""
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In BaseNode, this is just a pass-through to `process_one`.
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Subclasses (like Node with retry) can override this to add extra logic.
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"""
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return await self.process_one(shared_storage, item)
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async def process(self, shared_storage, preprocess_result):
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"""
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Calls `robust_process_one` instead of `process_one` so that
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any subclass overrides of robust_process_one will apply.
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"""
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return await self.robust_process_one(shared_storage, preprocess_result)
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async def postprocess(self, shared_storage, preprocess_result, process_result):
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return "default"
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async def run_one(self, shared_storage):
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preprocess_result = await self.preprocess(shared_storage)
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process_result = await self.process(shared_storage, preprocess_result)
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condition = await self.postprocess(shared_storage, preprocess_result, process_result)
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if not self.successors:
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return None
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elif len(self.successors) == 1:
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return next(iter(self.successors.values()))
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return self.successors.get(condition)
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def run(self, shared_storage=None):
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return asyncio.run(self.run_async(shared_storage))
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async def run_async(self, shared_storage=None):
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shared_storage = shared_storage or {}
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current_node = self
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while current_node:
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current_node = await current_node.run_one(shared_storage)
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def __rshift__(self, other):
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return self.add_successor(other)
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def __gt__(self, other):
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if isinstance(other, str):
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return _ConditionalTransition(self, other)
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elif isinstance(other, BaseNode):
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return self.add_successor(other)
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raise TypeError("Unsupported operand type")
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def __call__(self, condition):
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return _ConditionalTransition(self, condition)
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class _ConditionalTransition:
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def __init__(self, source_node, condition):
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self.source_node = source_node
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self.condition = condition
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def __gt__(self, target_node):
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if not isinstance(target_node, BaseNode):
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raise TypeError("Target must be a BaseNode")
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return self.source_node.add_successor(target_node, self.condition)
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# ---------------------------------------------------------------------
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# Flow: allows you to define a "start_node" that is run in a sub-flow
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# ---------------------------------------------------------------------
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class Flow(BaseNode):
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def __init__(self, start_node=None):
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super().__init__()
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self.start_node = start_node
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async def process_one(self, shared_storage, item):
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# Instead of doing a single operation, we run a sub-flow
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if self.start_node:
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current_node = self.start_node
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while current_node:
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# Pass down the parameters
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current_node.set_parameters(self.parameters)
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current_node = await current_node.run_one(shared_storage or {})
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# ---------------------------------------------------------------------
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# Node: adds robust retry logic on top of BaseNode
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# ---------------------------------------------------------------------
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class Node(BaseNode):
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"""
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Retries its single-item operation up to `max_retries` times,
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waiting `delay_s` seconds between attempts.
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By default: max_retries=5, delay_s=0.1
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End developers simply override `process_one` to define logic.
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"""
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def __init__(self, max_retries=5, delay_s=0.1):
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super().__init__()
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self.parameters.setdefault("max_retries", max_retries)
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self.parameters.setdefault("delay_s", delay_s)
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async def fail_one(self, shared_storage, item, exc):
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"""
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Called if the final retry also fails. By default,
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just returns a special string or could log an error.
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End developers can override this to do something else
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(e.g., store the failure in a separate list or
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trigger alternative logic).
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"""
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# Example: log and return a special status
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print(f"[FAIL_ONE] item={item}, error={exc}")
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return "fail"
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async def robust_process_one(self, shared_storage, item):
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max_retries = self.parameters.get("max_retries", 5)
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delay_s = self.parameters.get("delay_s", 0.1)
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for attempt in range(max_retries):
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try:
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# Defer to the user's process_one logic
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return await super().robust_process_one(shared_storage, item)
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except Exception as e:
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if attempt == max_retries - 1:
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# Final attempt failed; call fail_one
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return await self.fail_one(shared_storage, item, e)
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# Otherwise, wait a bit and try again
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await asyncio.sleep(delay_s)
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# ---------------------------------------------------------------------
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# BatchMixin: processes a collection of items by calling robust_process_one for each
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# ---------------------------------------------------------------------
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class BatchMixin:
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async def process(self, shared_storage, items):
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"""
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Processes a *collection* of items in a loop, calling robust_process_one per item.
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"""
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partial_results = []
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for item in items:
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r = await self.robust_process_one(shared_storage, item)
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partial_results.append(r)
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return self.merge(shared_storage, partial_results)
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def merge(self, shared_storage, partial_results):
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"""
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Combines partial results into a single output.
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By default, returns the list of partial results.
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"""
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return partial_results
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async def preprocess(self, shared_storage):
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"""
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Typically, you'd return a list or collection of items to process here.
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By default, returns an empty list.
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"""
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return []
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# ---------------------------------------------------------------------
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# BatchNode: combines Node (robust logic) + BatchMixin (batch logic)
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# ---------------------------------------------------------------------
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class BatchNode(BatchMixin, Node):
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"""
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A batch-processing node that:
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- Inherits robust retry logic from Node
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- Uses BatchMixin to process a list of items
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"""
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async def preprocess(self, shared_storage):
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# Gather or return the batch items. By default, no items.
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return []
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async def process_one(self, shared_storage, item):
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"""
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The per-item logic that the end developer will override.
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By default, does nothing.
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"""
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return None
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# ---------------------------------------------------------------------
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# BatchFlow: combines Flow (sub-flow logic) + batch processing + robust logic
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# ---------------------------------------------------------------------
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class BatchFlow(BatchMixin, Flow):
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"""
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This class runs a sub-flow (start_node) for each item in a batch.
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If you also want robust retries, you can adapt or combine with `Node`.
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"""
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async def preprocess(self, shared_storage):
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# Return your batch items here
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return []
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async def process(self, shared_storage, items):
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"""
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For each item, run the sub-flow (start_node).
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"""
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results = []
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for item in items:
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# Here we re-run the sub-flow, which happens inside process_one of Flow
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await self.process_one(shared_storage, item)
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# Optionally collect results or do something after the sub-flow
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results.append(f"Finished sub-flow for item: {item}")
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return results |