Package com.rabbitmq.stream

Interface ObservationCollector<T>

public interface ObservationCollector<T>

API to instrument operations in the stream client. The supported operations are publishing, and asynchronous delivery.

Implementations can gather information and send it to tracing backends. This allows e.g. following the processing steps of a given message through different systems.

This is considered an SPI and is susceptible to change at any time.

Since:

0.12.0

See Also:

• EnvironmentBuilder.observationCollector(ObservationCollector)
• MicrometerObservationCollectorBuilder

Field Summary

Fields

Modifier and Type	Field	Description
static final ObservationCollector<Void>	NO_OP

Method Summary

Modifier and Type	Method	Description
default boolean	isNoop()	Says whether the implementation does nothing or not.
T	prePublish(String stream, Message message)	Start observation.
void	published(T context, Message message)	Callback when the message is about to be published.
MessageHandler	subscribe(MessageHandler handler)	Decorate consumer registration.

Field Details

NO_OP

static final ObservationCollector<Void> NO_OP

Method Details

prePublish

T prePublish(String stream,
 Message message)

Start observation.

Implementations are expecting to return an observation context that will be passed in to the published(Object, Message) callback.

Parameters:

stream - the stream to publish to

message - the message to publish

Returns:

observation context

published

void published(T context,
 Message message)

Callback when the message is about to be published.

Parameters:

context - the observation context

message - the message to publish

subscribe

MessageHandler subscribe(MessageHandler handler)

Decorate consumer registration.

Parameters:

handler - the original handler

Returns:

a decorated handler

isNoop

default boolean isNoop()

Says whether the implementation does nothing or not.

Returns:

true if the implementation is a no-op