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We are happy to announce a new major version of KumuluzEE Metrics - 2.0.1. This release implements the MicroProfile Metrics 2.0. Programming interface and REST format include a number of breaking changes which integrate the extension even better with popular cloud-native metric processing tools like Prometheus.

In order to avoid confusion, the monotonic flag has been removed from the @Counted annotation. All counters are now by default monotonic (increasing only). A new metric type has been added in order to compensate for monotonic flag removal - ConcurrentGauge (with accompanying annotation @ConcurrentGauge). This metric type also reports the minimum and maximum value reached in the previous minute.

The Metadata object used when programmatically creating metrics is now immutable and can be created by using the builder pattern (Metadata.builder()).

Following the Prometheus/OpenMetrics convention, a metric is now uniquely identifiable using a combination of both its name and tags (as opposed to just name). This combination is now represented as an MetricID object. Most of the MetricRegistry API has been updated accordingly.

JSON output format now appends tags to the end of the metrics names, allowing metrics with the same name to be reported at the same time. Prometheus output format was also changed in order to better respect the Prometheus best practices.

Features

• Implemented ConcurrentGauge and removed the monotonic flag from counters.
• Made metrics identifiable by name and tags (MetricID).
• Updated API for the MetricID change.
• Updated JSON and Prometheus serializers.

Enhancements

• Refactored Metadata usage to the immutable implementation.
• Updated Logs and Logstash reporters to use the new JSON format.
• Improved performance of the MetricRegistry implementation.
• Updated dependency versions.

More details about this release can be found on GitHub.