A PolicyMonitor extension component will be implemented.
Some transfer types, such as streaming never reach the COMPLETED state, so they need to be terminated whenever the
Policy on which the participants agreed is not valid anymore.
This component will be implemented using the same model as the state machine we're using for TransferProcess:
- The ingestion will be done with a listener on the
TransferProcessStartedevent, that will add an entry to aPolicyMonitorStore. - The state machine then will continuously fetch the oldest entries leasing them, check the related policy.
- If the check fails the TP will get completed through a service call (that could be either embedded in the control-plane
or remote through a rest call) and the entry will be removed from the
PolicyMonitorStore. - otherwise the lease will be broken and the policy be verified again in the next run.
- If the check fails the TP will get completed through a service call (that could be either embedded in the control-plane
or remote through a rest call) and the entry will be removed from the
With "leasing" we mean that the entity will be reserved by a connector instance that will be the only one allowed to modify it until the lease gets broken, and this can happen by updating it or after a certain amount of time.
This mechanism will permit to scale the process to multiple instances.
The PolicyMonitor will be deployable embedded in the control-plane or separately in a standalone runtime.
The PolicyMonitorStore will have a in-memory implementation for testing scenarios and a sql (postgres) one.