Reactive routing in Helidon MP

Since Helidon 1.4

Configuring a reactive route in Helidon MP

Helidon MP Server will pick up CDI beans that implement the io.helidon.webserver.Service interface and configure them with the underlying WebServer.

This allows configuration of reactive routes to run alongside a JAX-RS application.

The bean is expected to be either ApplicationScoped or Dependent and will be requested only once during the boot of the Server.

The bean will support injection of ApplicationScoped and Dependent scoped beans. You cannot inject RequestScoped beans. Please use WebServer features to handle request related objects.

Customizing the reactive service

The service can be customized using annotations and/or configuration to be

  • registered on a specific path

  • registered with a named routing

Assigning a reactive service to named ports

Helidon has the concept of named routings. These correspond to the named ports configured with WebServer.

You can assign a reactive service to a named routing (and as a result to a named port) using either an annotation or configuration (or both to override the value from annotation).

Annotation @RoutingName

You can annotated a service with this annotation to assign it to a specific named routing, that is (most likely) going to be bound to a specific port.

The annotation has two attributes: - value that defines the routing name - required to mark that the routing name MUST be configured in Helidon server

Example:

@ApplicationScoped
@RoutingName(value="admin", required="true")
@RoutingPath("/admin")
public class AdminService implements Service {
//....
}

The example above will be bound to admin routing (and port) and will fail if such a port is not configured.

Configuration override of routing name

For each service class you can define the routing name and its required flag by specifying a configuration option class-name.routing-name.name and class-name.routing-name.required.

Example (YAML) configuration for a class io.helidon.examples.AdminService that changes the routing name to management and its required flag to false:

io.helidon.examples.AdminService:
  routing-name:
    name: "management"
    required: false

Configuring a reactive service path

Each service is registered on a path. If none is configured, then the service would be configured on the root path.

You can configure service path using an annotation or configuration (or both to override value from annotation)

Annotation @RoutingPath

You can configure @RoutingPath to define the path a service is registered on.

Configuration override of routing path

For each reactive service class you can define the routing path by specifying a configuration option class-name.routing-path.path.

Example (YAML) configuration for a class io.helidon.example.AdminService that changes the routing path to /management:

io.helidon.examples.AdminService:
  routing-path:
    path: "/management"

Example configuration of reactive service

A full configuration example (YAML):

server:
  port: 8080
  sockets:
    management:
      port: 8090

io.helidon.examples.AdminService:
  routing-name:
    name: "management"
    required: true
  routing-path:
    path: "/management"