faust.models.base
¶
Model descriptions.
The model describes the components of a data structure, kind of like a struct in C, but there’s no limitation of what type of data structure the model is, or what it’s used for.
A record (faust.models.record) is a model type that serialize into dictionaries, so the model describe the fields, and their types:
>>> class Point(Record):
... x: int
... y: int
>>> p = Point(10, 3)
>>> assert p.x == 10
>>> assert p.y == 3
>>> p
<Point: x=10, y=3>
>>> payload = p.dumps(serializer='json')
'{"x": 10, "y": 3, "__faust": {"ns": "__main__.Point"}}'
>>> p2 = Record.loads(payload)
>>> p2
<Point: x=10, y=3>
Models are mainly used for describing the data in messages: both keys and values can be described as models.
-
faust.models.base.
registry
= {'@ClientAssignment': <class 'faust.assignor.client_assignment.ClientAssignment'>, '@ClientMetadata': <class 'faust.assignor.client_assignment.ClientMetadata'>, '@ClusterAssignment': <class 'faust.assignor.cluster_assignment.ClusterAssignment'>, '@ReqRepRequest': <class 'faust.agents.models.ReqRepRequest'>, '@ReqRepResponse': <class 'faust.agents.models.ReqRepResponse'>, 'faust.agents.models.ModelReqRepRequest': <class 'faust.agents.models.ModelReqRepRequest'>, 'faust.agents.models.ModelReqRepResponse': <class 'faust.agents.models.ModelReqRepResponse'>}¶ Global map of namespace -> Model, used to find model classes by name. Every single model defined is added here automatically when a model class is defined.
-
class
faust.models.base.
Model
(*args, **kwargs) → None[source]¶ Meta description model for serialization.
-
classmethod
loads
(s: bytes, *, default_serializer: Union[faust.types.codecs.CodecT, str, None] = None, serializer: Union[faust.types.codecs.CodecT, str, None] = None) → faust.types.models.ModelT[source]¶ Deserialize model object from bytes.
- Keyword Arguments
serializer (CodecArg) – Default serializer to use if no custom serializer was set for this model subclass.
- Return type
-
classmethod
-
class
faust.models.base.
FieldDescriptor
(field: str, type: Type, model: Type[faust.types.models.ModelT], required: bool = True, default: Any = None, parent: faust.types.models.FieldDescriptorT = None) → None[source]¶ Describes a field.
Used for every field in Record so that they can be used in join’s /group_by etc.
Examples
>>> class Withdrawal(Record): ... account_id: str ... amount: float = 0.0
>>> Withdrawal.account_id <FieldDescriptor: Withdrawal.account_id: str> >>> Withdrawal.amount <FieldDescriptor: Withdrawal.amount: float = 0.0>
- Parameters
-
field
= None¶ Name of attribute on Model.
-
type
= None¶ Type of value (e.g.
int
, orOptional[int]
)).
-
model
= None¶ The model class this field is associated with.
-
required
= True¶ Set if a value for this field is required (cannot be
None
).
-
default
= None¶ Default value for non-required field.