• Overview

• Maven Coordinates

• Usage

• Configuration

• Additional Information

• Reference

In Helidon 4 all observability features were moved to one logical module: observe. Observability features specified by MicroProfile—​such as metrics and health—​keep their familiar endpoints. The endpoints for other observability features are grouped together under a single context root which defaults to /observe.

You do not need to explicitly add any observability dependency in your Helidon MP project pom.xml file for MicroProfile technologies. Adding a dependency on Helidon’s MP metrics or health component, for example, brings along the necessary observability components automatically.

To include other observability features in your Helidon MP application, add one or more of the following dependencies.

For Info Observability features:

<dependency>
    <groupId>io.helidon.webserver.observe</groupId>
    <artifactId>helidon-webserver-observe-info</artifactId>
</dependency>

For Logging Observability features:

<dependency>
    <groupId>io.helidon.webserver.observe</groupId>
    <artifactId>helidon-webserver-observe-log</artifactId>
</dependency>

For Configuration Observability features:

<dependency>
    <groupId>io.helidon.webserver.observe</groupId>
    <artifactId>helidon-webserver-observe-config</artifactId>
</dependency>

The MicroProfile observability features use top-level endpoints (such as /health and /metrics) which you can customize if you wish. See the configuration section below for more information.

Other observability features add endpoints under the /observe path

Feature Weight and Endpoint Conflicts

server.features.observe.weight = 120

Endpoints

To customize the endpoint of an observer:

1. For MicroProfile technologies (metrics, health) refer to the Helidon MP documentation for them:

   • metrics config documentation

   • health config documentation

2. For other observers, assign a custom endpoint using a config setting such as server.features.observe.info.endpoint.

To control the observability features as a whole, add config settings under server.features.observe.

Configuration options

The Observability features are now implemented with HttpFeature and can be registered with HttpRouting.Builder#addFeature(java.util.function.Supplier). Such a feature encapsulates a set of endpoints, services and/or filters.

Feature is similar to HttpService but gives more freedom in setup. Main difference is that a feature can add Filter filters and it cannot be registered on a path (that is left to the discretion of the feature developer).

• Features are not registered immediately - each feature can define a Weight or implement Weighted to order features according to their weight. Higher weighted features are registered first.

• This is to allow ordering of features in a meaningful way (e.g. Context should be first, Tracing second, Security third etc).

• MicroProfile Metrics Specification

• Metrics documentation.

• Health documentation.