org.honton.chas.datadog.apm

Interface Tracer

All Known Implementing Classes:

TracerImpl

public interface Tracer

Tracer acts as span manager. Spans can be created and closed through this interface. Cross-process traces can be imported and exported.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	Tracer.HeaderAccessor A functional interface to access a header value.
static interface	Tracer.HeaderMutator A functional interface to set a header.

Field Summary

Fields

Modifier and Type	Field and Description
static String	SPAN_ID The name of the header containing the span identifier.
static String	TRACE_ID The name of the header containing the trace identifier.

Method Summary

Modifier and Type	Method and Description
void	closeCurrentSpan() Finish the current span and restore the current span's parent as the current span
void	closeSpan(SpanBuilder current) Finish the supplied span and restore the supplied span's parent as the current span.
SpanBuilder	createSpan() Create a span which is a child of the current span.
<T> T	executeCallable(String resource, String operation, Callable<T> callable) Execute a Callable with reporting
void	executeRunnable(String resource, String operation, Runnable runnable) Execute a Runnable with reporting
SpanBuilder.SpanContext	exportCurrentSpan() Export a span across a thread.
void	exportSpan(String resource, String operation, Tracer.HeaderMutator headerAccessor) Export a span to another process using headers.
SpanBuilder	getCurrentSpan() Get the currently active span
SpanBuilder	importCurrentSpan(SpanBuilder.SpanContext spanContext, String resource, String operation) Import a span across a thread.
SpanBuilder	importSpan(Tracer.HeaderAccessor headerAccessor) Import a span across process boundaries using a set of headers.

Field Detail

SPAN_ID

static final String SPAN_ID

The name of the header containing the span identifier.

See Also:

Constant Field Values

TRACE_ID

static final String TRACE_ID

The name of the header containing the trace identifier.

See Also:

Constant Field Values

Method Detail

executeCallable

<T> T executeCallable(String resource,
                      String operation,
                      Callable<T> callable)

Execute a Callable with reporting

Type Parameters:

T - The return type of the Callable

Parameters:

resource - The resource being called

operation - The operation being called

callable - The Callable to invoke

Returns:

The value returned from the Callable

executeRunnable

void executeRunnable(String resource,
                     String operation,
                     Runnable runnable)

Execute a Runnable with reporting

Parameters:

resource - The resource being called

operation - The operation being called

runnable - The runnable to invoke

getCurrentSpan

SpanBuilder getCurrentSpan()

Get the currently active span

Returns:

The current span, or null

exportCurrentSpan

SpanBuilder.SpanContext exportCurrentSpan()

Export a span across a thread. Must be called from the exporting Thread. WARNING: Exporting a thread does not prevent the closure of parent span. It may look like asynchronous behavior in the APM dashboard.

Returns:

A SpanContext

importCurrentSpan

SpanBuilder importCurrentSpan(SpanBuilder.SpanContext spanContext,
                              String resource,
                              String operation)

Import a span across a thread. Must be called from the importing Thread. getCurrentSpan() must be called from the exporting Thread. WARNING: Importing a thread will destroy the current threads stack of spans!

Parameters:

spanContext - A SpanContext from exportCurrentSpan()

resource - The resource for the new span

operation - The operation for the new span

Returns:

The SpanBuilder which is a child of the imported span.

importSpan

SpanBuilder importSpan(Tracer.HeaderAccessor headerAccessor)

Import a span across process boundaries using a set of headers.

Parameters:

headerAccessor - The function access to headers. Function supplied with header name and should return the header value.

Returns:

The SpanBuilder which is a child of the imported span.

exportSpan

void exportSpan(String resource,
                String operation,
                Tracer.HeaderMutator headerAccessor)

Export a span to another process using headers. Creates a span in this process.

Parameters:

resource - The remote resource being invoked

operation - The remote operation being invoked

headerAccessor - The function access to headers. Function supplied with header name and value.

createSpan

SpanBuilder createSpan()

Create a span which is a child of the current span. The newly created span is now considered the current span.

Returns:

The child span, to be filled with resource and operation.

closeCurrentSpan

void closeCurrentSpan()

Finish the current span and restore the current span's parent as the current span

closeSpan

void closeSpan(SpanBuilder current)

Finish the supplied span and restore the supplied span's parent as the current span. This method is called from finally blocks and must not throw any exceptions.

Parameters:

current - The currently active span