com.google.instrumentation.trace

Class BinaryPropagationHandler

java.lang.Object

com.google.instrumentation.trace.BinaryPropagationHandler

public abstract class BinaryPropagationHandler
extends Object

This is a helper class for SpanContext propagation on the wire using binary encoding.

Example of usage on the client:

 private static final Tracer tracer = Tracing.getTracer();
 private static final BinaryPropagationHandler binaryPropagationHandler =
     Tracing.getBinaryPropagationHandler();
 void onSendRequest() {
   try (NonThrowingCloseable ss = tracer.spanBuilder("Sent.MyRequest").startScopedSpan()) {
     byte[] binaryValue = binaryPropagationHandler.toBinaryValue(
         tracer.getCurrentContext().context());
     // Send the request including the binaryValue and wait for the response.
   }
 }
 

Example of usage on the server:

 private static final Tracer tracer = Tracing.getTracer();
 private static final BinaryPropagationHandler binaryPropagationHandler =
     Tracing.getBinaryPropagationHandler();
 void onRequestReceived() {
   // Get the binaryValue from the request.
   SpanContext spanContext = SpanContext.INVALID;
   try {
     if (binaryValue != null) {
       spanContext = binaryPropagationHandler.fromBinaryValue(binaryValue);
     }
   } catch (ParseException e) {
     // Maybe log the exception.
   }
   try (NonThrowingCloseable ss =
            tracer.spanBuilderWithRemoteParent(spanContext, "Recv.MyRequest").startScopedSpan()) {
     // Handle request and send response back.
   }
 }
 

Constructor Summary

Constructors

Constructor and Description
BinaryPropagationHandler()

Method Summary

Modifier and Type	Method and Description
abstract SpanContext	fromBinaryValue(byte[] bytes) Parses the SpanContext from the binary format.
abstract byte[]	toBinaryValue(SpanContext spanContext) Serializes a SpanContext using the binary format.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BinaryPropagationHandler

public BinaryPropagationHandler()

Method Detail

toBinaryValue

public abstract byte[] toBinaryValue(SpanContext spanContext)

Serializes a SpanContext using the binary format.

Parameters:

spanContext - the SpanContext to serialize.

Returns:

the serialized binary value.

Throws:

NullPointerException - if the spanContext is null.

fromBinaryValue

public abstract SpanContext fromBinaryValue(byte[] bytes)
                                     throws ParseException

Parses the SpanContext from the binary format.

Parameters:

bytes - a binary encoded buffer from which the SpanContext will be parsed.

Returns:

the parsed SpanContext.

Throws:

NullPointerException - if the input is null.

ParseException - if the version is not supported or the input is invalid