databay.inlet

See also

• Extending Inlets to learn how to extend this class correctly.

• Outlet representing the corresponding output of the data stream.

class databay.inlet.Inlet(metadata: dict = None)

databay.inlet.Inlet

Abstract class representing an input of the data stream.

Parameters

metadata (dict) – Global metadata that will be attached to each record generated by this inlet. It can be overridden or appended to by providing metadata when creating a record using new_record() function.

Default:

None

Bases: abc.ABC

metadata(self)

property

Global metadata that will be attached to each record generated by this inlet. It can be overridden or appended to by providing metadata when creating a record using new_record() function.

Returns

Metadata dictionary.

Return type

dict

pull(self, update: da.Update) → List[Record]

abstractmethod

Produce new data.

Override this method to define how this inlet will produce new data.

Parameters

update (Update) – Update object representing the particular Link update run.

Returns

List of records produced

Return type

list[Record]

new_record(self, payload, metadata: dict = None) → Record

Create a new Record. This should be the preferred way of creating new records.

Parameters

• payload (Any) – Data produced by this inlet.

• metadata (dict) – Local metadata that will override and/or append to the global metadata. It will be attached to the new record.

  Default:
  None

Returns

New record created

Return type

Record

try_start(self)

Wrapper around on_start call that will ensure it only gets executed once.

on_start(self)

Called once per inlet just before the governing planner is about to start.

Override this method to provide starting functionality on this inlet.

try_shutdown(self)

Wrapper around on_shutdown call that will ensure it only gets executed once.

on_shutdown(self)

Called once per inlet just after the governing planner has shutdown.

Override this method to provide shutdown functionality on this inlet.

active(self)

property

Whether this inlet is active and ready to pull. This variable is set by the governing link to True on start and to False on shutdown.

Default:

False

Return type

bool