Interface Tracer

All Known Implementing Classes:

OtlpTracer

public interface Tracer

Where spans come from and where they go.

The server is instrumented against this interface and nothing else, so a binary that installs no tracer carries no tracing implementation: the translator keeps a class only when something reaches it, and the one implementation, com.codename1.backend.otel.OtlpTracer, is reached only from the entry point the build generates for a project that asks for it (see @OpenTelemetry).

Method Summary

Modifier and Type	Method	Description
void	flush(int timeoutMillis)	Blocks until what has ended so far is exported, or the time runs out.
void	metrics(Map out)	Adds this tracer's counters to a metrics snapshot.
boolean	open(Config config)	Reads the settings and starts whatever exports spans.
HttpServer.Handler	relay()	The handler that relays client spans to the collector, or null when this deployment does not offer one.
void	shutdown(int timeoutMillis)	Flushes, then stops the exporter.
Span	startSpan(String name, int kind, Span parent, String traceparent, String tracestate)	A new span.

Method Details

open

boolean open(Config config)
      throws IOException

Reads the settings and starts whatever exports spans. Called once, by Backend.Builder.start() or by the application before Tracing.install(Tracer).

Returns:

false when the configuration turned tracing off, in which case the tracer is not installed and nothing was started

Throws:

IOException

startSpan

Span startSpan(String name,
 int kind,
 Span parent,
 String traceparent,
 String tracestate)

A new span. Never null: a span the sampler declines is a non-recording one that still carries its trace context.

Parameters:

parent - the local parent, or null

traceparent - a remote parent's traceparent header, used when parent is null; null or malformed starts a new trace

tracestate - the remote parent's tracestate, or null

flush

void flush(int timeoutMillis)

Blocks until what has ended so far is exported, or the time runs out. A Lambda host freezes the process between invocations, so a background exporter there only runs when something waits for it.

shutdown

void shutdown(int timeoutMillis)

Flushes, then stops the exporter.

relay

HttpServer.Handler relay()

The handler that relays client spans to the collector, or null when this deployment does not offer one. The builder puts it ahead of the routers.

metrics

void metrics(Map out)

Adds this tracer's counters to a metrics snapshot.