databay.link¶

Contents:

`Update`	Data structure representing one Link transfer. When converted to string returns `{tags}.{transfer_number}`
`Link`	Link in the relationship graph. Use this class to define relationships between inlets and outlets.

class databay.link.Update(tags: List[str], transfer_number: int)[source]¶

databay.link.Update

Data structure representing one Link transfer. When converted to string returns {tags}.{transfer_number}

Parameters

tags (List[str]) – Tags of the link, see: Link.
transfer_number (int) – Incremental identifier of the current transfer.

class databay.link.Link(inlets: Union[Inlet, List[Inlet]], outlets: Union[Outlet, List[Outlet]], interval: Union[datetime.timedelta, int, float], tags: Union[str, List[str]] = None, copy_records: bool = True, ignore_exceptions: bool = False, catch_exceptions: bool = None, inlet_concurrency: int = 9999, immediate_transfer: bool = True, processors: Union[callable, List[callable]] = None, groupers: Union[callable, List[callable]] = None, name=None)[source]¶

databay.link.Link

Link in the relationship graph. Use this class to define relationships between inlets and outlets.

Parameters

inlets (Inlet or list[Inlet]) – inlets to add to this link.
outlets (Outlet or list[Outlet]) – outlets to add to this link.
interval (Union[datetime.timedelta, int, float]) – Expects datetime.timedelta. Alternatively, you can provide int or float which will be coerced explicitly to datetime.timedelta.seconds.
tags (Union[str, List[str]]) – List of tags of this link.
Default:
[]
copy_records (bool) – Whether to copy records before passing them to outlets.
Default:
True
ignore_exceptions (bool) – Whether exceptions in inlets and outlets should be logged and ignored, or raised.
Default:
True
inlet_concurrency (int) – How many inlets are allowed to execute concurrently.
Default:
9999
immediate_transfer (bool) – Whether governing planners that have BasePlanner.immediate_transfer set to True should execute this link’s transfer once immediately upon starting.
Default:
True
processors (callable or list[callable]) – Processors of this link.
Default:
None
groupers (callable or list[callable]) – groupers of this link.
Default:
None

inlets(self) → List[Inlet][source]¶

property

Inlets handled by this link.

Returns: list[Inlet]

add_inlets(self, inlets: Union[Inlet, List[Inlet]])[source]¶

Add inlets to this link. Inlets must be of type Inlet and not currently added to this link.

Parameters: inlets (Inlet or list[Inlet]) – inlets to add to this link
Raises: InvalidNodeError if this link already contains any of the inlets being added.

remove_inlets(self, inlets: Union[Inlet, List[Inlet]])[source]¶

Remove inlets from this link.

Parameters: inlets (Inlet or list[Inlet]) – inlets to remove from this link
Raises: InvalidNodeError if this link doesn’t contain any of the inlets being removed.

outlets(self) → List[Outlet][source]¶

property

Outlets handled by this link.

Returns: list[Outlet]

add_outlets(self, outlets: Union[Outlet, List[Outlet]])[source]¶

Add outlets to this link. Outlets must be of type Outlet and not currently added to this link.

Parameters: outlets (Outlet or list[Outlet]) – outlets to add to this link
Raises: InvalidNodeError if this link already contains any of the outlets being added.

remove_outlets(self, outlets: Union[Outlet, List[Outlet]])[source]¶

Remove outlets from this link.

Parameters: outlets (Outlet or list[Outlet]) – outlets to remove from this link
Raises: InvalidNodeError if this link doesn’t contain any of the outlets being removed.

interval(self) → datetime.timedelta [source]¶

property

Frequency at which this link should transfer.

Returns: interval object
Return type: datetime.timedelta

set_job(self, job)[source]¶

Parameters: job (Any) – specify the job this link is executed with.

job(self) → Any[source]¶

property

The job this link is executed with. Job should persist between link transfers.

Default:

None

Returns: Job this link is executed with.

name(self) → str [source]¶

property

Deprecated in 0.2.0, will be removed in 1.0. Use Link.tags instead.

Name of this Link, equivalent to first tag of this link.

Returns: Name of this link
Return type: str

tags(self) → List[str][source]¶

property

The tags of this link.

Default:

[]

Returns: Tags of this link
Return type: List[str]

transfer(self)[source]¶

Execute one transfer on this link. This will run through all inlets querying them for data, then pass that data to all outlets.

See Link transfer to learn more about the transfer.

on_start(self)[source]¶

Called when the governing planner is about to start. Calls try_start on all inlets and outlets of this link.

If an inlet or outlet is present in multiple links its on_start will only be called once by whichever link executes first.

on_shutdown(self)[source]¶

Called just after the governing planner has shutdown. Calls try_shutdown on all inlets and outlets of this link.

If an inlet or outlet is present in multiple links its on_shutdown will only be called once by whichever link executes first.