nanover.state.state_service module

Module providing an implementation of the StateServicer.

class nanover.state.state_service.StateService

Bases: StateServicer

Implementation of the State service, for tracking and making changes to a shared key/value store.

SubscribeStateUpdates(request: SubscribeStateUpdatesRequest, context) → Iterable[StateUpdate]: Provides a stream of updates to a shared key/value store.

UpdateLocks(request: UpdateLocksRequest, context) → UpdateLocksResponse: Attempts to acquire and release locks on keys in the shared key/value store. If any of the locks cannot be acquired, none of them will be.

UpdateState(request: UpdateStateRequest, context) → UpdateStateResponse: Attempts an atomic update of the shared key/value store. If any key cannot be updates, no change will be made.

close()

copy_state() → Dict[str, None | str | int | float | bool | Iterable[Any] | Mapping[str, Any] | Iterable[None | str | int | float | bool | Iterable[Any] | Mapping[str, Any]] | Mapping[str, None | str | int | float | bool | Iterable[Any] | Mapping[str, Any]]]: Return a deep copy of the current state.

get_change_buffer() → ContextManager[DictionaryChangeBuffer]: Return a DictionaryChangeBuffer that tracks changes to this service’s state.

lock_state() → ContextManager[Dict[str, None | str | int | float | bool | Iterable[Any] | Mapping[str, Any] | Iterable[None | str | int | float | bool | Iterable[Any] | Mapping[str, Any]] | Mapping[str, None | str | int | float | bool | Iterable[Any] | Mapping[str, Any]]]]: Context manager for reading the current state while delaying any changes to it.

state_dictionary: StateDictionary

Attempts to acquire and release locks on keys in the shared key/value store. If any of the locks cannot be acquired, none of them will be. Requested lock releases are carried out regardless.

Raises:: ResourceLockedError – if the access token cannot acquire all requested keys.

Attempts an atomic update of the shared key/value store. If any key cannot be updated, no change will be made.

Raises:

ResourceLockedError – if the access token cannot acquire all keys for updating.
TypeError – if the update values cannot be serialized for transmission.

nanover.state.state_service.dictionary_change_to_state_update(change: DictionaryChange) → StateUpdate

Convert a DictionaryChange to a protobuf StateUpdate.

Parameters:: change – a DictionaryChange which species key changes and key removals to make to a dictionary.
Returns:: an equivalent protobuf StateUpdate representing the key removals as key changes to a protobuf null value.

nanover.state.state_service.locks_update_to_acquire_release(update: UpdateLocksRequest) → Tuple[Dict[str, float], Set[str]]: Convert a grpc UpdateLocksRequest to a tuple of lock times and locked keys to release.

nanover.state.state_service.state_update_to_dictionary_change(update: StateUpdate) → DictionaryChange

Convert a protobuf StateUpdate to a DictionaryChange.

Parameters:: update – a protobuf StateUpdate which encodes key removals as keys with a protobuf null value.
Returns:: an equivalent DictionaryChange representing the key changes and key removals of the StateUpdate.

nanover.state.state_service.validate_dict_is_serializable(dictionary)

Raises:: TypeError – if the given dictionary cannot be converted to a protobuf struct.