Suite UUIDs

[hjoliver]

• restart with real tasks still running - suite port likely to change #204 (comment)
• 215 job submission retry (no polling of submitted tasks yet) #364 (comment)

[hjoliver]

[meeting] we agreed suite should pass UUID to tasks, which use it in return comms. Do with comms refactor #1872.

[matthewrmshin]

I propose to do this:

• cylc run creates a new UUID for a suite, and stores it in the suite runtime database.
• cylc restart loads the UUID from the suite runtime database.
• Writes UUID in the suite contact file.
• Writes UUID in task job environment.
• cylc message will only send message to suite if the UUID in task job environment is the same as the UUID in the suite contact file.
  • (This is probably good enough. A slightly more complete solution is to have cylc message send the UUID with the message as well, and the suite should reject the message if it is different from its current UUID.)