Broadcast Dowsampler

class RobotRaconteur.BroadcastDownsampler(context, default_downsample=0)

Downsampler to manage rate of packets sent to client

PipeBroadcaster and WireBroadcaster by default sends packets to all clients when a pipe packet is sent or the wire value is changed. The updates typically happen within a sensor or control loop, with the rate set by the specific device producing the updates. Some clients may require less frequent data, and may run in to bandwidth or processing issues if the data is sent at the full update rate. The BroadcastDownsampler is used to implement broadcaster predicates that will drop packets. Clients specify how many packets they want dropped between each packet sent. For instance, a downsample of 0 means that no packets are dropped. A downsample of 1 will drop every other packet. A downsample of two will drop 2 packets between sending 1 packet, etc. The downsample level for each client is set using SetClientDownsample(). This should be made available to the client using a property member.

PipeBroadcaster and WireBroadcaster must be added to the downsampler using AddPipeBroadcaster() and AddWireBroadcaster(), respectively. It is recommended that these functions be called within the RRServiceObjectInit(context,servicepath) function thit is called by the node when a service object is initialized.

BeginStep() and EndStep() must be called for each iteration of the broadcasting loop. Use BroadcastDownsamplerStep for automatic management in the loop.

See com.robotraconteur.isoch.IsochDevice for the standard use of downsampling.

AddPipeBroadcaster(broadcaster)

Add a PipeBroadcaster to the downsampler

Sets the predicate of the broadcaster to this downsampler

Parameters:

broadcaster (PipeBroadcaster) – The pipe broadcaster to add

AddWireBroadcaster(broadcaster)

Add a WireBroadcaster to the downsampler

Sets the predicate of the broadcaster to this downsampler

Parameters:

broadcaster (PipeBroadcaster) – The pipe broadcaster to add

BeginStep()

Begin the update loop step

Use BroadcastDownsamplerStep for automatic stepping

EndStep()

End the update loop step

Use BroadcastDownsamplerStep for automatic stepping

GetClientDownsample(ep)

Get the downsample for the specified client

Parameters:

ep (int) – The endpoint ID of the client

Returns:

The downsample

Return type:

int

SetClientDownsample(ep, downsample)

Set the downsample for the specified client

Parameters:

• ep (int) – The endpoint ID of the client

• downsample (int) – The desired downsample

class RobotRaconteur.BroadcastDownsamplerStep(downsampler)

Class for automatic broadcast downsampler stepping

Helper class to automate BroadcastDownsampler stepping. Calls BroadcastDownsampler.BeginStep() on construction, and BroadcastDownsampler.EndStep() on destruction.

Use with a “with” block