Metrics

Metrics is a service helping developers to measure various metrics inside their code, for example, methods' execution time.

Relevant Bundles

• skysail.api - interface definitions and Noop Implementations.
• skysail.core - utilises metrics if (at least) one implementation is available in the runtime.
• skysail.ext.metrics (repo: skysail-ex) - bundle providing an MetricsImplementation based on Dropwizard.
• skysail.server.app.metrics - access to collected metrics and visualisation.

Supported Metrics

• Counters - increment and decrement an integer (e.g. count of current active sessions)
• Histogram - measures the distribution of values in a stream of data: e.g., the number of results returned by a search
• Meter - measures the _rate _at which a set of events occur: e.g., requests per minute
• Timer - measure the duration (and distribution) of a type of event: e.g., page rendering.

Usage

If you extend a SkysailApplication, you can use the method getMetricsCollector() and use it like this to create a timer metric:

TimerMetric timerMetric = getMetricsCollector().timerFor(this.getClass(), "getEntities");
List<T> response = listEntities();
timerMetric.stop();

Other metric types can be used accordingly.