=== 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>3.6.1</version>
</dependency>
----

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

[source,groovy,subs="+attributes"]
----
compile 'io.vertx:vertx-service-discovery-bridge-zookeeper:3.6.1'
----

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.zookeeper.ZookeeperServiceImporter"))(), {
  "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,js]
----
var ServiceDiscovery = require("vertx-service-discovery-js/service_discovery");
ServiceDiscovery.create(vertx).registerServiceImporter(new (Java.type("io.vertx.servicediscovery.zookeeper.ZookeeperServiceImporter"))(), {
  "connection" : "127.0.0.1:2181",
  "maxRetries" : 5,
  "baseSleepTimeBetweenRetries" : 2000,
  "basePath" : "/services"
});

----