yr.InstanceProxy.snapstart

InstanceProxy.snapstart(checkpoint_id: str) → InstanceProxy

Start a new instance from a snapshot.

This method creates a new instance by restoring from a previously created snapshot, sending signal 19 (INSTANCE_SNAPSTART_SIGNAL) through the Kill interface. The new instance will have the same state as when the snapshot was taken.

Parameters:

checkpoint_id (str) – The checkpoint ID returned by the snapshot() method. Format: {instanceID}-{functionID}-{uuid}

Returns:

A new instance proxy for the restored instance.

Return type:

InstanceProxy

Raises:

RuntimeError – If the checkpoint does not exist or restore operation fails.

Example

>>> import yr
>>> yr.init()
>>>
>>> @yr.instance
... class MyInstance:
...     def __init__(self):
...         self.counter = 0
...
...     def increment(self):
...         self.counter += 1
...         return self.counter
...
...     def __yr_after_snapstart__(self):
...         print(f"Instance restored, counter={self.counter}")
...
>>> # Create instance and snapshot
>>> ins = MyInstance.invoke()
>>> yr.get(ins.increment.invoke())  # counter = 1
>>> checkpoint_id = ins.snapshot(leave_running=False)
>>>
>>> # Restore from snapshot
>>> restored_ins = MyInstance.snapstart(checkpoint_id)
>>> result = yr.get(restored_ins.increment.invoke())  # counter = 2
>>> print(f"Counter after restore: {result}")
>>>
>>> yr.finalize()