Program State Transition for 4.3

Assumptions

• State change message will be sent after action is performed successfully (so that the action timestamp < message timestamp)
• No out of order messages (based on message timestamp)
• STARTING is safe state change -> no multiple messages, no missed messages, no out of order messages

Changes required

Program state change writer

• Store the latest message timestamp along with the run record during update
• Ignore a message if message timestamp is equal or less than what is recorded
• Update code to match the new states in the state diagram (the new changes are in red color)
• Publish the finally resolved program state message transactionally along with the store update to a new topic

Run record corrector

• Run record corrector will only process run records before the last processed message time

Scheduler

• Make scheduler listen to the changes published by the program state change writer

State Transition Diagram