Interface MetricReader

All Superinterfaces:

AggregationTemporalitySelector, AutoCloseable, Closeable, DefaultAggregationSelector

All Known Implementing Classes:

PeriodicMetricReader

public interface MetricReader
extends AggregationTemporalitySelector, DefaultAggregationSelector, Closeable

A metric reader reads metrics from an SdkMeterProvider.

Since:

1.14.0

Method Summary

Modifier and Type	Method	Description
default void	close()	Close this MetricReader, releasing any resources.
CompletableResultCode	forceFlush()	Read and export the metrics.
default Aggregation	getDefaultAggregation(InstrumentType instrumentType)	Return the default aggregation for the InstrumentType.
default MemoryMode	getMemoryMode()	Returns the memory mode used by this reader.
void	register(CollectionRegistration registration)	Called by SdkMeterProvider on initialization to supply the MetricReader with MetricProducers used to collect metrics.
CompletableResultCode	shutdown()	Shuts down the metric reader.

Methods inherited from interface AggregationTemporalitySelector

getAggregationTemporality

Methods inherited from interface DefaultAggregationSelector

with

Method Details

register

void register(CollectionRegistration registration)

Called by SdkMeterProvider on initialization to supply the MetricReader with MetricProducers used to collect metrics. MetricReader implementations call CollectionRegistration.collectAllMetrics() to read metrics.

getDefaultAggregation

default Aggregation getDefaultAggregation(InstrumentType instrumentType)

Return the default aggregation for the InstrumentType.

Specified by:

getDefaultAggregation in interface DefaultAggregationSelector

Since:

1.16.0

See Also:

• DefaultAggregationSelector.getDefaultAggregation(InstrumentType)

getMemoryMode

default MemoryMode getMemoryMode()

Returns the memory mode used by this reader.

Returns:

The MemoryMode used by this instance

Since:

1.31.0

forceFlush

CompletableResultCode forceFlush()

Read and export the metrics.

Called when SdkMeterProvider.forceFlush() is called.

Returns:

the result of the flush.

shutdown

CompletableResultCode shutdown()

Shuts down the metric reader.

Called when SdkMeterProvider.shutdown() is called.

For pull based readers like prometheus, this should shut down the metric hosting endpoint or server doing such a job.

For push based readers like MetricExporter, this should shut down any scheduler threads.

Returns:

the result of the shutdown.

close

default void close()
            throws IOException

Close this MetricReader, releasing any resources.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Throws:

IOException