|
| 1 | +# -*- coding: utf-8 -*- |
| 2 | + |
| 3 | +""" |
| 4 | +Batch processing utilities |
| 5 | +""" |
| 6 | + |
| 7 | +import logging |
| 8 | +from abc import ABC, abstractmethod |
| 9 | +from typing import Any, Callable, Dict, List, Tuple |
| 10 | + |
| 11 | +from aws_lambda_powertools.middleware_factory import lambda_handler_decorator |
| 12 | + |
| 13 | +logger = logging.getLogger(__name__) |
| 14 | + |
| 15 | + |
| 16 | +class BasePartialProcessor(ABC): |
| 17 | + """ |
| 18 | + Abstract class for batch processors. |
| 19 | + """ |
| 20 | + |
| 21 | + def __init__(self): |
| 22 | + self.success_messages: List = [] |
| 23 | + self.fail_messages: List = [] |
| 24 | + self.exceptions: List = [] |
| 25 | + |
| 26 | + @abstractmethod |
| 27 | + def _prepare(self): |
| 28 | + """ |
| 29 | + Prepare context manager. |
| 30 | + """ |
| 31 | + raise NotImplementedError() |
| 32 | + |
| 33 | + @abstractmethod |
| 34 | + def _clean(self): |
| 35 | + """ |
| 36 | + Clear context manager. |
| 37 | + """ |
| 38 | + raise NotImplementedError() |
| 39 | + |
| 40 | + @abstractmethod |
| 41 | + def _process_record(self, record: Any): |
| 42 | + """ |
| 43 | + Process record with handler. |
| 44 | + """ |
| 45 | + raise NotImplementedError() |
| 46 | + |
| 47 | + def process(self) -> List[Tuple]: |
| 48 | + """ |
| 49 | + Call instance's handler for each record. |
| 50 | + """ |
| 51 | + return [self._process_record(record) for record in self.records] |
| 52 | + |
| 53 | + def __enter__(self): |
| 54 | + self._prepare() |
| 55 | + return self |
| 56 | + |
| 57 | + def __exit__(self, exception_type, exception_value, traceback): |
| 58 | + self._clean() |
| 59 | + |
| 60 | + def __call__(self, records: List[Any], handler: Callable): |
| 61 | + """ |
| 62 | + Set instance attributes before execution |
| 63 | +
|
| 64 | + Parameters |
| 65 | + ---------- |
| 66 | + records: List[Any] |
| 67 | + List with objects to be processed. |
| 68 | + handler: Callable |
| 69 | + Callable to process "records" entries. |
| 70 | + """ |
| 71 | + self.records = records |
| 72 | + self.handler = handler |
| 73 | + return self |
| 74 | + |
| 75 | + def success_handler(self, record: Any, result: Any): |
| 76 | + """ |
| 77 | + Success callback |
| 78 | +
|
| 79 | + Returns |
| 80 | + ------- |
| 81 | + tuple |
| 82 | + "success", result, original record |
| 83 | + """ |
| 84 | + entry = ("success", result, record) |
| 85 | + self.success_messages.append(record) |
| 86 | + return entry |
| 87 | + |
| 88 | + def failure_handler(self, record: Any, exception: Exception): |
| 89 | + """ |
| 90 | + Failure callback |
| 91 | +
|
| 92 | + Returns |
| 93 | + ------- |
| 94 | + tuple |
| 95 | + "fail", exceptions args, original record |
| 96 | + """ |
| 97 | + entry = ("fail", exception.args, record) |
| 98 | + logger.debug(f"Record processing exception: {exception}") |
| 99 | + self.exceptions.append(exception) |
| 100 | + self.fail_messages.append(record) |
| 101 | + return entry |
| 102 | + |
| 103 | + |
| 104 | +@lambda_handler_decorator |
| 105 | +def batch_processor( |
| 106 | + handler: Callable, event: Dict, context: Dict, record_handler: Callable, processor: BasePartialProcessor = None |
| 107 | +): |
| 108 | + """ |
| 109 | + Middleware to handle batch event processing |
| 110 | +
|
| 111 | + Parameters |
| 112 | + ---------- |
| 113 | + handler: Callable |
| 114 | + Lambda's handler |
| 115 | + event: Dict |
| 116 | + Lambda's Event |
| 117 | + context: Dict |
| 118 | + Lambda's Context |
| 119 | + record_handler: Callable |
| 120 | + Callable to process each record from the batch |
| 121 | + processor: PartialSQSProcessor |
| 122 | + Batch Processor to handle partial failure cases |
| 123 | +
|
| 124 | + Examples |
| 125 | + -------- |
| 126 | + **Processes Lambda's event with PartialSQSProcessor** |
| 127 | + >>> from aws_lambda_powertools.utilities.batch import batch_processor, PartialSQSProcessor |
| 128 | + >>> |
| 129 | + >>> def record_handler(record): |
| 130 | + >>> return record["body"] |
| 131 | + >>> |
| 132 | + >>> @batch_processor(record_handler=record_handler, processor=PartialSQSProcessor()) |
| 133 | + >>> def handler(event, context): |
| 134 | + >>> return {"StatusCode": 200} |
| 135 | +
|
| 136 | + Limitations |
| 137 | + ----------- |
| 138 | + * Async batch processors |
| 139 | +
|
| 140 | + """ |
| 141 | + records = event["Records"] |
| 142 | + |
| 143 | + with processor(records, record_handler): |
| 144 | + processor.process() |
| 145 | + |
| 146 | + return handler(event, context) |
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