Chapter 42. Etcd

Etcd Component

Etcd is a distributed key value store that provides a reliable way to store data across a cluster of machines.
Maven users will need to add the following dependency to their pom.xml for this component. 
<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-etcd</artifactId>
    <!-- use the same version as your Camel core version -->
    <version>x.y.z</version>
</dependency>

URI format

etcd:namespace[/path][?options]
Where namespace represents the etcd context to which the etcd-component should operate and path is an optional attribute to define which node is being impacted.
Supported namespaces are:
  • keys
  • watch
  • stats

Options

Name
Default Value
Description
uris
http://localhost:2379,http://localhost:4001
Defines the URIs the component should connect to.
sslContextParameters null To use a custom org.apache.camel.util.jsse.SSLContextParameters. See Using the JSSE Configuration Utility
userName null The user name to use for basic authentication
password null The password to use for basic authentication
sendEmptyExchangeOnTimeout false To send an empty message in case of timeout watching for a key (consumer only)
recursive false To apply an action recursively
timeToLive null To set the lifespan of a key in milliseconds
timeout null To set the maximum time an action could take to complete.

Headers

NameTypeDescription
CamelEtcdAction java.lang.String The action to perform, supported values are set, delete, deleteDir, get
CamelEtcdNamespace java.lang.String
The etcd context an exchange was generated/processed from
CamelEtcdPath java.lang.String
For keys namespace, it is used to determine the node subject the the action, if not set the path from URI endpoint is used. For stats and watch namespaces it contains the path of the node beign processed
CamelEtcdTimeout java.lang.Long To set the maximum time an action could take to complete. If not present, the timeout option is taken into account
CamelEtcdTtl java.lang.Integer To set the lifespan of a key in milliseconds. If not present, the timeToLive option is taken into account
CamelEtcdRecursive java.lang.Boolean To apply an action recursively. If not present, the recursive option is taken into account.

Keys namespace example:

CamelContext context = new DefaultCamelContext();
context.addRoutes(new RouteBuilder() {
    public void configure() {
       from("direct:keys-set")
            .to("etcd:keys")
                .to("log:camel-etcd?level=INFO");
    }
});

Map<String, Object> headers = new HashMap<>();
headers.put(EtcdConstants.ETCD_ACTION, EtcdConstants.ETCD_KEYS_ACTION_SET);
headers.put(EtcdConstants.ETCD_PATH, "/camel/etcd/myKey");
 
ProducerTemplate template = context.createProducerTemplate();
template.sendBodyAndHeaders("direct:keys-set", "camel-etcd", headers);

Stats namespace example:

CamelContext context = new DefaultCamelContext();
context.addRoutes(new RouteBuilder() {
    public void configure() {
       from("etcd:stats/leader?consumer.delay=50&consumer.initialDelay=0")
           .to("log:etcd-leader-stats?level=INFO");
       from("etcd:stats/self?consumer.delay=50&consumer.initialDelay=0")
           .to("log:etcd-self-stats?level=INFO");
       from("etcd:stats/store?consumer.delay=50&consumer.initialDelay=0")
           .to("log:etcd-store-stats?level=INFO");
    }
});

Watch namespace example:

CamelContext context = new DefaultCamelContext();
context.addRoutes(new RouteBuilder() {
    public void configure() {
       from("etcd:watch/recursive?recursive=true")
        .marshall().json()
        .to("log:etcd-event?level=INFO")
    }
});