Package io.grpc.xds.orca

Class OrcaPerRequestUtil

  • @ExperimentalApi("https://github.com/grpc/grpc-java/issues/9128")
public abstract class OrcaPerRequestUtil
extends java.lang.Object
    Utility class that provides method for LoadBalancer to install listeners to receive per-request backend cost metrics in the format of Open Request Cost Aggregation (ORCA).

    • Field Detail

      • NOOP_CLIENT_STREAM_TRACER

        private static final io.grpc.ClientStreamTracer NOOP_CLIENT_STREAM_TRACER

      • NOOP_CLIENT_STREAM_TRACER_FACTORY

        private static final io.grpc.ClientStreamTracer.Factory NOOP_CLIENT_STREAM_TRACER_FACTORY

    • Constructor Detail

      • OrcaPerRequestUtil

        public OrcaPerRequestUtil()

    • Method Detail

      • newOrcaClientStreamTracerFactory

        public abstract io.grpc.ClientStreamTracer.Factory newOrcaClientStreamTracerFactory​(OrcaPerRequestUtil.OrcaPerRequestReportListener listener)
        Creates a new ClientStreamTracer.Factory with provided OrcaPerRequestUtil.OrcaPerRequestReportListener installed to receive callback when a per-request ORCA report is received.

        Example usages for leaf level policy (e.g., WRR policy) 

           
   class WrrPicker extends SubchannelPicker {

     public PickResult pickSubchannel(PickSubchannelArgs args) {
       Subchannel subchannel = ...  // WRR picking logic
       return PickResult.withSubchannel(
           subchannel,
           OrcaPerRequestReportUtil.getInstance().newOrcaClientStreamTracerFactory(listener));
     }
   }
        Parameters:
        listener - contains the callback to be invoked when a per-request ORCA report is received.

      • newOrcaClientStreamTracerFactory

        public abstract io.grpc.ClientStreamTracer.Factory newOrcaClientStreamTracerFactory​(io.grpc.ClientStreamTracer.Factory delegate,
                                                                                    OrcaPerRequestUtil.OrcaPerRequestReportListener listener)
        Creates a new ClientStreamTracer.Factory with provided OrcaPerRequestUtil.OrcaPerRequestReportListener installed to receive callback when a per-request ORCA report is received.

        Example usages:

        • Delegating policy (e.g., xDS) 
                 
       class XdsPicker extends SubchannelPicker {

         public PickResult pickSubchannel(PickSubchannelArgs args) {
           SubchannelPicker perLocalityPicker = ...  // locality picking logic
           Result result = perLocalityPicker.pickSubchannel(args);
           return PickResult.withSubchannel(
               result.getSubchannel(),
               OrcaPerRequestReportUtil.getInstance().newOrcaClientTracerFactory(
                   result.getStreamTracerFactory(), listener));

         }
       }
        • Delegating policy with additional tracing logic 
                 
       class WrappingPicker extends SubchannelPicker {

         public PickResult pickSubchannel(PickSubchannelArgs args) {
           Result result = delegate.pickSubchannel(args);
           return PickResult.withSubchannel(
               result.getSubchannel(),
               new ClientStreamTracer.Factory() {
                 public ClientStreamTracer newClientStreamTracer(
                     StreamInfo info, Metadata metadata) {
                   ClientStreamTracer.Factory orcaTracerFactory =
                       OrcaPerRequestReportUtil.getInstance().newOrcaClientStreamTracerFactory(
                           result.getStreamTracerFactory(), listener);

                   // Wrap the tracer from the delegate factory if you need to trace the
                   // stream for your own.
                   final ClientStreamTracer orcaTracer =
                       orcaTracerFactory.newClientStreamTracer(info, metadata);

                   return ForwardingClientStreamTracer() {
                     protected ClientStreamTracer delegate() {
                       return orcaTracer;
                     }

                     public void inboundMessage(int seqNo) {
                       // Handle this event.
                       ...
                     }
                   };
                 }
               });
         }
       }
        Parameters:
        delegate - the delegate factory to produce other client stream tracing.
        listener - contains the callback to be invoked when a per-request ORCA report is received.

      • fromOrcaLoadReport

        static io.grpc.services.MetricReport fromOrcaLoadReport​(OrcaLoadReport loadReport)