Episodic coordination model for distributed applications

摘要

An episodic execution of program instances and a coordinated message exchange protocol are combined to achieve eventual consistency in the communication between nodes of a distributed system. Program instances run in episodic loops that are triggered by defined input events and that generate checkpoints. The checkpoints indicate when messages are to be sent from the one instance to another instance or other device. The coordinated message exchange protocol allows the instance to send a message to a receiver, to acknowledge that the message has been received, and to confirm the acknowledgement to the receiver.

主权项

1. A method, comprising:
completing an episode of execution of a first instance of first program code running on a processor; running the episode of execution until a checkpoint state is achieved; recording checkpoint data; proceeding to a send and confirm state; identifying one or more messages to be sent from the first instance to a second instance of second program code; sending a first message from the first instance to the second instance; receiving a second message from the second instance, the second message comprising an acknowledgement indicating that the first message was received at the second instance; sending a third message from the first instance to the second instance, the third message comprising a confirmation indicating that the second message was received at the first instance; receiving a fourth message from the second instance, the fourth message comprising a confirmation-acknowledgement indicating that the third message was received at the second instance; compare additional events to a specified new input; and when an additional event matches the specified new input, execute another episode of the instance.