ygaller / consul-client

Java Client for Consul HTTP API

Consul Client for Java

Simple client for the Consul HTTP API. For more information about the Consul HTTP API, go here.

Installation

###Bintray:

Grab the latest binary (0.8.1) here.

###Gradle:

Note: Maven Central inclusion pending. Should be available soon.

repositories {
    jcenter() // or mavenCentral()
}

dependencies {
    compile 'com.orbitz.consul:consul-client:0.8.1'
}

###Maven:

<dependencies>
    <dependency>
        <groupId>com.orbitz.consul</groupId>
        <artifactId>consul-client</artifactId>
        <version>0.8.1</version>
    </dependency>
</dependencies>

Basic Usage

Example 1: Register and check your service in with Consul. Note that you need to continually check in before the TTL expires, otherwise your service's state will be marked as "critical".

Consul consul = Consul.newClient(); // connect to Consul on localhost
AgentClient agentClient = consul.agentClient();

String serviceName = "MyService";
String serviceId = "1";

agentClient.register(8080, 3L, serviceName, serviceId); // registers with a TTL of 3 seconds
agentClient.pass(); // check in with Consul

Example 2: Find available (healthy) services.

Consul consul = Consul.newClient(); // connect to Consul on localhost
HealthClient healthClient = consul.healthClient();

<List<ServiceHealth> nodes = healthClient.getHealthyNodes("DataService").getResponse(); // discover only "passing" nodes

Example 3: Store key/values.

Consul consul = Consul.newClient(); // connect to Consul on localhost
KeyValueClient kvClient = consul.keyValueClient();

kvClient.putValue("foo", "bar");

String value = kvClient.getValueAsString("foo").get(); // bar

Example 4: Blocking call for value.

import static com.orbitz.consul.option.QueryOptionsBuilder;

Consul consul = Consul.newClient();
KeyValueClient kvClient = consul.keyValueClient();

kvClient.putValue("foo", "bar");

Value value = kvClient.getValue("foo", builder().blockMinutes(10, 120).build()).get(); // will block (long poll) for 10 minutes or until "foo"'s value changes.

Example 5: Blocking call for healthy services using callback.

Consul consul = Consul.newClient();
final HealthClient healthClient = consul.healthClient();

ConsulResponseCallback<List<ServiceHealth>> callback = new ConsulResponseCallback<List<ServiceHealth>>() {

    int index;

    @Override
    public void onComplete(ConsulResponse<List<ServiceHealth>> consulResponse) {
        for(ServiceHealth health : consulResponse.getResponse()) {
            String host = health.getNode().getAddress();
            int port = health.getService().getPort();

            // do something with this service information
        }

        index = consulResponse.getIndex();

        // blocking request with new index
        healthClient.getHealthyNodes("my-service", builder().blockMinutes(5, index).build(), this);
    }

    @Override
    public void onFailure(Throwable throwable) {
        throwable.printStackTrace();
        healthClient.getHealthyNodes("my-service", builder().blockMinutes(5, index).build(), this);
    }
};

healthClient.getHealthyNodes("my-service", builder().blockMinutes(1, 0).build());

Example 6: Find Raft peers.

StatusClient statusClient = Consul.newClient().statusClient();

for(String peer : statusClient.getPeers()) {
	System.out.println(peer); // 127.0.0.1:8300
}

Example 7: Find Raft leader.

StatusClient statusClient = Consul.newClient().statusClient();

System.out.println(statusClient.getLeader()); // 127.0.0.1:8300