=== Zookeeper bridge

This discovery bridge imports services from https://zookeeper.apache.org/[Apache Zookeeper] into the Vert.x service
discovery. The bridge uses the http://curator.apache.org/curator-x-discovery/[Curator extension for service discovery].

Service description are read as JSON Object (merged in the Vert.x service record metadata). The service type is
deduced from this description by reading the `service-type`.

==== 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-zookeeper</artifactId>
 <version>4.4.3</version>
</dependency>
----

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

[source,groovy,subs="+attributes"]
----
compile 'io.vertx:vertx-service-discovery-bridge-zookeeper:4.4.3'
----

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

[source, java]
----
ServiceDiscovery.create(vertx)
    .registerServiceImporter(new ZookeeperServiceImporter(),
        new JsonObject()
            .put("connection", "127.0.0.1:2181"));
----

Only the `connection` configuration is mandatory. It's the connection _string_ of the Zookeeper server.

In addition you can configure:

* `maxRetries`: the number of connection attempt, 3 by default
* `baseSleepTimeBetweenRetries`: the amount of milliseconds to wait between retries (exponential backoff strategy).
1000 ms by default.
* `basePath`: the Zookeeper path in which the service are stored. Default to `/discovery`.
* `connectionTimeoutMs`: the connection timeout in milliseconds. Defaults to 1000.
* `canBeReadOnly` : whether or not the backend support the _read-only_ mode (defaults to true)

[source,java]
----
ServiceDiscovery.create(vertx)
    .registerServiceImporter(new ZookeeperServiceImporter(),
        new JsonObject()
            .put("connection", "127.0.0.1:2181")
            .put("maxRetries", 5)
            .put("baseSleepTimeBetweenRetries", 2000)
            .put("basePath", "/services")
    );
----