io.opentracing

Interface Tracer

public interface Tracer

Tracer is a simple, thin interface for Span creation and propagation across arbitrary transports.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	Tracer.SpanBuilder

Method Summary

Modifier and Type	Method and Description
Tracer.SpanBuilder	buildSpan(String operationName) Return a new SpanBuilder for a Span with the given `operationName`.
SpanContext	extract(Object carrier) Extract a SpanContext from a `carrier` of a given type, presumably after propagation across a process boundary.
void	inject(SpanContext spanContext, Object carrier) Inject a SpanContext into a `carrier` of a given type, presumably for propagation across process boundaries.

Method Detail

buildSpan

Tracer.SpanBuilder buildSpan(String operationName)

Return a new SpanBuilder for a Span with the given `operationName`.

A contrived example:

    Tracer tracer = ...

    Span parentSpan = tracer.buildSpan("DoWork")
                            .start();

    Span http = tracer.buildSpan("HandleHTTPRequest")
                      .asChildOf(parentSpan.context())
                      .withTag("user_agent", req.UserAgent)
                      .withTag("lucky_number", 42)
                      .start();
    

inject

void inject(SpanContext spanContext,
            Object carrier)

Inject a SpanContext into a `carrier` of a given type, presumably for propagation across process boundaries.

Example:

 Tracer tracer = ...
 Span clientSpan = ...
 HttpHeaderWriter httpHeaderWriter = new AnHttpHeaderCarrier(httpRequest);
 tracer.inject(span.context(), httpHeaderWriter);
 

Parameters:

spanContext - the SpanContext instance to inject into the carrier

carrier - the carrier for the SpanContext state; when inject() returns, the Tracer implementation will have represented the SpanContext within `carrier`. All Tracer.inject() implementations must support io.opentracing.propagation.TextMapWriter, io.opentracing.propagation.HttpHeaderWriter, and java.nio.ByteBuffer.

See Also:

io.opentracing.propagation

extract

SpanContext extract(Object carrier)

Extract a SpanContext from a `carrier` of a given type, presumably after propagation across a process boundary.

Example:

 Tracer tracer = ...
 HttpHeaderReader httpHeaderReader = new AnHttpHeaderCarrier(httpRequest);
 SpanContext spanCtx = tracer.extract(httpHeaderReader);
 tracer.buildSpan('...').withChildOf(spanCtx).start();
 

If the span serialized state is invalid (corrupt, wrong version, etc) inside the carrier this will result in an IllegalArgumentException.

Parameters:

carrier - the carrier for the SpanContext state. All Tracer.extract() implementations must support io.opentracing.propagation.TextMapReader, io.opentracing.propagation.HttpHeaderReader, and java.nio.ByteBuffer.

See Also:

io.opentracing.propagation