Package io.helidon.metrics

Class MetricsSupport

java.lang.Object

io.helidon.metrics.MetricsSupport

All Implemented Interfaces:

Service

public final class MetricsSupport
extends Object
implements Service

Support for metrics for Helidon Web Server.

By defaults cretes the /metrics endpoint with three sub-paths: application, vendor and base.

To register with web server:

 Routing.builder()
        .register(MetricsSupport.create())
 

This class supports finer grained configuration using Helidon Config: create(Config). The following configuration parameters can be used:

Configuration parameters

key	default value	description
helidon.metrics.context	/metrics	Context root under which the rest endpoints are available
helidon.metrics.base.${metricName}.enabled	true	Can control which base metrics are exposed, set to false to disable a base metric

The application metrics registry is then available as follows:

  req.context().get(MetricRegistry.class).ifPresent(reg -> reg.counter("myCounter").inc());
 

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MetricsSupport.Builder A fluent API builder to build instances of MetricsSupport.

Method Summary

Modifier and Type	Method and Description
static MetricsSupport.Builder	builder() Create a new builder to construct an instance.
void	configureEndpoint(Routing.Rules rules) Configure metrics endpoint on the provided routing rules.
void	configureVendorMetrics(String routingName, Routing.Rules rules) Configure vendor metrics on the provided routing.
static MetricsSupport	create() Create an instance to be registered with Web Server with all defaults.
static MetricsSupport	create(Config config) Create an instance to be registered with Web Server maybe overriding default values with configured values.
static String	toPrometheusData(Metric metric) Returns the Prometheus data for the specified Metric.
void	update(Routing.Rules rules) Method invoked by the web server to update routing rules.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

create

public static MetricsSupport create()

Create an instance to be registered with Web Server with all defaults.

Returns:

a new instance built with default values (for context, base metrics enabled)

create

public static MetricsSupport create(Config config)

Create an instance to be registered with Web Server maybe overriding default values with configured values.

Parameters:

config - Config instance to use to (maybe) override configuration of this component. See class javadoc for supported configuration keys.

Returns:

a new instance configured withe config provided

builder

public static MetricsSupport.Builder builder()

Create a new builder to construct an instance.

Returns:

A new builder instance

toPrometheusData

public static String toPrometheusData(Metric metric)

Returns the Prometheus data for the specified Metric.

Not every Metric supports conversion to Prometheus data. This method checks the metric first before performing the conversion, throwing an IllegalArgumentException if the metric cannot be converted.

Parameters:

metric - the Metric to convert to Prometheus format

Returns:

String containing the Prometheus data

configureVendorMetrics

public void configureVendorMetrics(String routingName,
                                   Routing.Rules rules)

Configure vendor metrics on the provided routing. This method is exclusive to update(io.helidon.webserver.Routing.Rules) (e.g. you should not use both, as otherwise you would duplicate the metrics)

Parameters:

routingName - name of the routing (may be null)

rules - routing builder or routing rules

configureEndpoint

public void configureEndpoint(Routing.Rules rules)

Configure metrics endpoint on the provided routing rules. This method just adds the endpoint /metrics (or appropriate one as configured). For simple routings, just register MetricsSupport instance. This method is exclusive to update(io.helidon.webserver.Routing.Rules) (e.g. you should not use both, as otherwise you would register the endpoint twice)

Parameters:

rules - routing rules (also accepts Routing.Builder

update

public void update(Routing.Rules rules)

Method invoked by the web server to update routing rules. Register this instance with webserver through Routing.Builder.register(io.helidon.webserver.Service...) rather than calling this method directly. If multiple sockets (and routings) should be supported, you can use the configureEndpoint(io.helidon.webserver.Routing.Rules), and configureVendorMetrics(String, io.helidon.webserver.Routing.Rules) methods.

Specified by:

update in interface Service

Parameters:

rules - a routing rules to update