| ################################################################################ |
| # Licensed to the Apache Software Foundation (ASF) under one |
| # or more contributor license agreements. See the NOTICE file |
| # distributed with this work for additional information |
| # regarding copyright ownership. The ASF licenses this file |
| # to you under the Apache License, Version 2.0 (the |
| # "License"); you may not use this file except in compliance |
| # with the License. You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| ################################################################################ |
| |
| from google.protobuf.any_pb2 import Any |
| import inspect |
| |
| from statefun.kafka_egress_pb2 import KafkaProducerRecord |
| from statefun.kinesis_egress_pb2 import KinesisEgressRecord |
| |
| class SdkAddress(object): |
| def __init__(self, namespace, type, identity): |
| self.namespace = namespace |
| self.type = type |
| self.identity = identity |
| |
| def __repr__(self): |
| return "%s/%s/%s" % (self.namespace, self.type, self.identity) |
| |
| def typename(self): |
| return "%s/%s" % (self.namespace, self.type) |
| |
| |
| class AnyStateHandle(object): |
| def __init__(self, any_bytes): |
| self.any = None |
| self.value_bytes = any_bytes |
| self.modified = False |
| self.deleted = False |
| |
| def bytes(self): |
| if self.deleted: |
| raise AssertionError("can not obtain the bytes of a delete handle") |
| if self.modified: |
| return self.value.SerializeToString() |
| else: |
| return self.value_bytes |
| |
| def unpack(self, into_class): |
| if self.value: |
| into_ref = into_class() |
| self.value.Unpack(into_ref) |
| return into_ref |
| else: |
| return None |
| |
| def pack(self, message): |
| any = Any() |
| any.Pack(message) |
| self.value = any |
| |
| @property |
| def value(self): |
| """returns the current value of this state""" |
| if self.deleted: |
| return None |
| if self.any: |
| return self.any |
| if not self.value_bytes: |
| return None |
| self.any = Any() |
| self.any.ParseFromString(self.value_bytes) |
| return self.any |
| |
| @value.setter |
| def value(self, any): |
| """updates this value to the supplied value, and also marks this state as modified""" |
| self.any = any |
| self.value_bytes = None |
| self.modified = True |
| self.deleted = False |
| |
| @value.deleter |
| def value(self): |
| """marks this state as deleted and also as modified""" |
| self.any = None |
| self.value_bytes = None |
| self.deleted = True |
| self.modified = True |
| |
| |
| class StatefulFunction(object): |
| def __init__(self, fun, expected_messages=None): |
| self.known_messages = expected_messages[:] if expected_messages else None |
| self.func = fun |
| if not fun: |
| raise ValueError("function code is missing.") |
| |
| def unpack_any(self, any: Any): |
| if self.known_messages is None: |
| return None |
| for cls in self.known_messages: |
| if any.Is(cls.DESCRIPTOR): |
| instance = cls() |
| any.Unpack(instance) |
| return instance |
| |
| raise ValueError("Unknown message type " + any.type_url) |
| |
| |
| def parse_typename(typename): |
| """parses a string of type namespace/type into a tuple of (namespace, type)""" |
| if typename is None: |
| raise ValueError("function type must be provided") |
| idx = typename.rfind("/") |
| if idx < 0: |
| raise ValueError("function type must be of the from namespace/name") |
| namespace = typename[:idx] |
| if not namespace: |
| raise ValueError("function type's namespace must not be empty") |
| type = typename[idx + 1:] |
| if not type: |
| raise ValueError("function type's name must not be empty") |
| return namespace, type |
| |
| |
| def deduce_protobuf_types(fn): |
| """ |
| Try to extract the class names that are attached as the typing annotation. |
| |
| :param fn: the function with the annotated parameters. |
| :return: a list of classes or None. |
| """ |
| spec = inspect.getfullargspec(fn) |
| if not spec: |
| return None |
| if len(spec.args) != 2: |
| raise TypeError("A stateful function must have two arguments: a context and a message. but got ", spec.args) |
| message_arg_name = spec.args[1] # has to be the second element |
| if message_arg_name not in spec.annotations: |
| return None |
| message_annotation = spec.annotations[message_arg_name] |
| if inspect.isclass(message_annotation): |
| return [message_annotation] |
| try: |
| # it is not a class, then it is only allowed to be |
| # typing.SpecialForm('Union') |
| return list(message_annotation.__args__) |
| except Exception: |
| return None |
| |
| |
| class StatefulFunctions: |
| def __init__(self): |
| self.functions = {} |
| |
| def register(self, typename: str, fun): |
| """registers a StatefulFunction function instance, under the given namespace with the given function type. """ |
| if fun is None: |
| raise ValueError("function instance must be provided") |
| namespace, type = parse_typename(typename) |
| expected_messages = deduce_protobuf_types(fun) |
| self.functions[(namespace, type)] = StatefulFunction(fun, expected_messages) |
| |
| def bind(self, typename): |
| """wraps a StatefulFunction instance with a given namespace and type. |
| for example: |
| s = StateFun() |
| |
| @s.define("com.foo.bar/greeter") |
| def greeter(context, message): |
| print("Hi there") |
| |
| This would add an invokable stateful function that can accept messages |
| sent to "com.foo.bar/greeter". |
| """ |
| |
| def wrapper(function): |
| self.register(typename, function) |
| return function |
| |
| return wrapper |
| |
| def for_type(self, namespace, type): |
| return self.functions[(namespace, type)] |
| |
| |
| def kafka_egress_record(topic: str, value, key: str = None): |
| """ |
| Build a ProtobufMessage that can be emitted to a Kafka generic egress. |
| |
| :param topic: The Kafka destination topic for that record |
| :param key: the utf8 encoded string key to produce (can be empty) |
| :param value: the Protobuf value to produce |
| :return: A Protobuf message representing the record to be produced via the Kafka generic egress. |
| """ |
| if not topic: |
| raise ValueError("A destination Kafka topic is missing") |
| if not value: |
| raise ValueError("Missing value") |
| record = KafkaProducerRecord() |
| record.topic = topic |
| record.value_bytes = value.SerializeToString() |
| if key is not None: |
| record.key = key |
| return record |
| |
| def kinesis_egress_record(stream: str, value, partition_key: str, explicit_hash_key: str = None): |
| """ |
| Build a ProtobufMessage that can be emitted to a Kinesis generic egress. |
| |
| :param stream: The AWS Kinesis destination stream for that record |
| :param partition_key: the utf8 encoded string partition key to use |
| :param value: the Protobuf value to produce |
| :param explicit_hash_key: a utf8 encoded string explicit hash key to use (can be empty) |
| :return: A Protobuf message representing the record to be produced to AWS Kinesis via the Kinesis generic egress. |
| """ |
| if not stream: |
| raise ValueError("Missing destination Kinesis stream") |
| if not value: |
| raise ValueError("Missing value") |
| if not partition_key: |
| raise ValueError("Missing partition key") |
| record = KinesisEgressRecord() |
| record.stream = stream |
| record.value_bytes = value.SerializeToString() |
| record.partition_key = partition_key |
| if explicit_hash_key is not None: |
| record.explicit_hash_key = explicit_hash_key |
| return record |
