Package brave.propagation

Class TraceContext

java.lang.Object

brave.propagation.SamplingFlags

brave.propagation.TraceContext

public abstract class TraceContext
extends SamplingFlags

Contains trace identifiers and sampling data propagated in and out-of-process.

Particularly, this includes trace identifiers and sampled state.

The implementation was originally com.github.kristofa.brave.SpanId, which was a port of com.twitter.finagle.tracing.TraceId. Unlike these mentioned, this type does not expose a single binary representation. That's because propagation forms can now vary.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	TraceContext.Builder
static interface	TraceContext.Extractor<C>	Used to join an incoming trace.
static interface	TraceContext.Injector<C>	Used to send the trace context downstream.

Field Summary

Fields inherited from class brave.propagation.SamplingFlags

DEBUG, EMPTY, NOT_SAMPLED, SAMPLED

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)	Only includes mandatory fields traceIdHigh(), traceId(), spanId()
abstract List<Object>	extra()	Returns a list of additional data propagated through this trace.
int	hashCode()	Only includes mandatory fields traceIdHigh(), traceId(), spanId()
static TraceContext.Builder	newBuilder()
abstract Long	parentId()	The parent's spanId() or null if this the root span in a trace.
abstract Boolean	sampled()	Should we sample this request or not? True means sample, false means don't, null means we defer decision to someone further down in the stack.
abstract boolean	shared()	True if we are contributing to a span started by another tracer (ex on a different host).
abstract long	spanId()	Unique 8-byte identifier of this span within a trace.
abstract TraceContext.Builder	toBuilder()
String	toString()	Returns $traceId/$spanId
abstract long	traceId()	Unique 8-byte identifier for a trace, set on all spans within it.
abstract long	traceIdHigh()	When non-zero, the trace containing this span uses 128-bit trace identifiers.
String	traceIdString()	Returns the hex representation of the span's trace ID

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from class brave.propagation.SamplingFlags

debug

Method Detail

newBuilder

public static TraceContext.Builder newBuilder()

traceIdHigh

public abstract long traceIdHigh()

When non-zero, the trace containing this span uses 128-bit trace identifiers.

traceId

public abstract long traceId()

Unique 8-byte identifier for a trace, set on all spans within it.

parentId

@Nullable
public abstract Long parentId()

The parent's spanId() or null if this the root span in a trace.

sampled

@Nullable
public abstract Boolean sampled()

Description copied from class: SamplingFlags

Should we sample this request or not? True means sample, false means don't, null means we defer decision to someone further down in the stack.

Specified by:

sampled in class SamplingFlags

spanId

public abstract long spanId()

Unique 8-byte identifier of this span within a trace.

A span is uniquely identified in storage by (traceId(), spanId()).

shared

public abstract boolean shared()

True if we are contributing to a span started by another tracer (ex on a different host). Defaults to false.

When an RPC trace is client-originated, it will be sampled and the same span ID is used for the server side. However, the server shouldn't set span.timestamp or duration since it didn't start the span.

extra

public abstract List<Object> extra()

Returns a list of additional data propagated through this trace.

The contents are intentionally opaque, deferring to Propagation to define. An example implementation could be storing a class containing a correlation value, which is extracted from incoming requests and injected as-is onto outgoing requests.

toBuilder

public abstract TraceContext.Builder toBuilder()

traceIdString

public String traceIdString()

Returns the hex representation of the span's trace ID

toString

public String toString()

Returns $traceId/$spanId

Overrides:

toString in class Object

equals

public boolean equals(Object o)

Only includes mandatory fields traceIdHigh(), traceId(), spanId()

Overrides:

equals in class Object

hashCode

public int hashCode()

Only includes mandatory fields traceIdHigh(), traceId(), spanId()

Overrides:

hashCode in class Object