messaging.messages package¶
Submodules¶
messaging.messages.chain module¶
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class
messaging.messages.chain.ChainCommandMessage¶ Bases:
messaging.messages.message.CommandMessage-
execute()¶
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static
from_json(json_dict)¶
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to_json()¶
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messaging.messages.echo module¶
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class
messaging.messages.echo.EchoCommandMessage¶ Bases:
messaging.messages.message.CommandMessage-
execute()¶
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static
from_json(json_dict)¶
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to_json()¶
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messaging.messages.factory module¶
Defines the factory for creating messages
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messaging.messages.factory.add_message_type(message_class)¶ Registers a message class so it can be used for Scale messaging
Parameters: message_class (class:messaging.messages.CommandMessage) – The class definition for a message
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messaging.messages.factory.get_message_type(message_type)¶ Returns a message class of the given type
Parameters: - message_type (string) – The unique identifier of a registered message type
- message_class (class:messaging.messages.CommandMessage) – The class definition for a message
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messaging.messages.factory.get_message_types()¶ Returns a list of type identifiers for all registered message types
Returns: A list of messages types Return type: [string]
messaging.messages.fail module¶
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class
messaging.messages.fail.FailCommandMessage¶ Bases:
messaging.messages.message.CommandMessage-
execute()¶
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static
from_json(json_dict)¶
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to_json()¶
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messaging.messages.message module¶
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class
messaging.messages.message.CommandMessage(message_type)¶ Bases:
objectThis ABC defines the interface all CommandMessage classes should implement.
If a CommandMessage needs to chain processing together, it should define this via the new_messages array.
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execute()¶ Processing logic for all command messages should be implemented within this method.
It is critical that execution of messages is idempotent - no side effects as result of repeated executions. Without idempotency we cannot support messaging backends such as SQS which guarantee ‘at least once’ delivery. No assurances are provided for message ordering, due to the asynchronous nature of messaging system with many potential message producers and consumers.
Returns: Success or failure of execute operation Return type: bool
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static
from_json(json_dict)¶ JSON deserializer for CommandMessage subclasses. Must be implemented in all subclasses.
Parameters: json_dict (dict) – CommandMessage JSON representation to reconstitute into class instance. Returns: Instantiated class from input JSON Return type: messaging.messages.CommandMessage
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to_json()¶ JSON Serializer for CommandMessage subclasses. Must be implemented in all subclasses.
Returns: JSON representation of CommandMessage class. Return type: dict
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