=== Docker Links bridge

This discovery bridge imports services from Docker Links into the Vert.x service discovery.

When you link a Docker
container to another Docker container, Docker injects a set of environment variables. This bridge analyzes these
environment variables and imports service record for each link. The service type is deduced from the `service.type`
label. If not set, the service is imported as `unknown`. Only `http-endpoint` are supported for now.

As the links are created when the container starts, the imported records are created when the bridge starts and
do not change afterwards.

==== Using the bridge

To use this Vert.x discovery bridge, add the following dependency to the _dependencies_ section of your build
descriptor:

* Maven (in your `pom.xml`):

[source,xml,subs="+attributes"]
----
<dependency>
  <groupId>io.vertx</groupId>
  <artifactId>vertx-service-discovery-bridge-docker-links</artifactId>
  <version>3.4.2</version>
</dependency>
----

* Gradle (in your `build.gradle` file):

[source,groovy,subs="+attributes"]
----
compile 'io.vertx:vertx-service-discovery-bridge-docker-links:3.4.2'
----

Then, when creating the service discovery, registers this bridge as follows:

[source, js]
----
var ServiceDiscovery = require("vertx-service-discovery-js/service_discovery");
ServiceDiscovery.create(vertx).registerServiceImporter(new (Java.type("io.vertx.servicediscovery.docker.DockerLinksServiceImporter"))(), {
});

----

The bridge does not need any further configuration.