= JGroups raft Component
:doctitle: JGroups raft
:shortname: jgroups-raft
:artifactid: camel-jgroups-raft
:description: Exchange messages with JGroups-raft clusters.
:since: 2.24
:supportlevel: Stable
:component-header: Both producer and consumer are supported
//Manually maintained attributes
:camel-spring-boot-name: jgroups-raft

*Since Camel {since}*

*{component-header}*

http://belaban.github.io/jgroups-raft/[JGroups-raft] is a https://raftconsensus.github.io/[Raft] implementation in http://www.jgroups.org/[JGroups].
The *jgroups-raft:* component provides interoperability between camel and a JGroups-raft clusters.

Maven users will need to add the following dependency to their `pom.xml`
for this component.

[source,xml]
------------------------------------------------------------
<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-jgroups-raft</artifactId>
    <!-- use the same version as your Camel core version -->
    <version>x.y.z</version>
</dependency>
------------------------------------------------------------

== URI format

-----------------------------
jgroups-raft:clusterName[?options]
-----------------------------

Where *clusterName* represents the name of the JGroups-raft cluster the
component should connect to.

== Options

// component-configure options: START

// component-configure options: END

// component options: START
include::partial$component-configure-options.adoc[]
include::partial$component-endpoint-options.adoc[]
// component options: END

// endpoint options: START

// endpoint options: END


== Headers

[width="100%",cols="10%,10%,70%",options="header",]
|=======================================================================
|Header |Constant |Since version |Description

|`JGROUPSRAFT_COMMIT_INDEX` |`JGroupsRaftEndpoint.HEADER_JGROUPSRAFT_COMMIT_INDEX` | *Consumer* : The commit index (int).

|`JGROUPSRAFT_CURRENT_TERM` |`JGroupsRaftEndpoint.`HEADER_JGROUPSRAFT_CURRENT_TERM` | *Consumer* : The current raft term (int).

|`JGROUPSRAFT_IS_LEADER` |`JGroupsRaftEndpoint.`HEADER_JGROUPSRAFT_IS_LEADER` | *Consumer*: Whether the node is the Raft Leader or not (boolean).

|`JGROUPSRAFT_LAST_APPLIED` |`JGroupsRaftEndpoint.`HEADER_JGROUPSRAFT_LAST_APPLIED` | *Consumer*: The index of the last log entry that was appended to the log (int).

|`JGROUPSRAFT_LEADER_ADDRESS` |`JGroupsRaftEndpoint.`HEADER_JGROUPSRAFT_LEADER_ADDRESS` | *Consumer*: The Address ot Raft Leader or not (org.jgroups.Address).

|`JGROUPSRAFT_LOG_SIZE` |`JGroupsRaftEndpoint.`HEADER_JGROUPSRAFT_LOG_SIZE` | *Consumer*: The Raft log size in number of entries (int).

|`JGROUPSRAFT_LOG_SIZE_BYTE` |`JGroupsRaftEndpoint.`HEADER_JGROUPSRAFT_LOG_SIZE_BYTE` | *Consumer*: The Raft log size in bytes (int).

|`JGROUPSRAFT_RAFT_ID` |`JGroupsRaftEndpoint.`HEADER_JGROUPSRAFT_RAFT_ID` | *Consumer*: The Raft id of the node (String).

|`JGROUPSRAFT_EVENT_TYPE` |`JGroupsRaftEndpoint.`HEADER_JGROUPSRAFT_EVENT_TYPE` | *Consumer*: The event type, one of org.apache.camel.component.jgroups.raft.JGroupsRaftEventType ENUM.

|`JGROUPSRAFT_SET_OFFSET` |`JGroupsRaftEndpoint.`HEADER_JGROUPSRAFT_SET_OFFSET` | *Producer*: Offset to use in the byte[] buffer to be set().

|`JGROUPSRAFT_SET_LENGTH` |`JGroupsRaftEndpoint.`HEADER_JGROUPSRAFT_SET_LENGTH` | *Producer*: Length to use in the byte[] buffer to be set().

|`JGROUPSRAFT_SET_TIMEOUT` |`JGroupsRaftEndpoint.`HEADER_JGROUPSRAFT_SET_TIMEOUT` | *Producer*: Timeout to be used in set() operation.

|`JGROUPSRAFT_SET_TIMEUNIT` |`JGroupsRaftEndpoint.`HEADER_JGROUPSRAFT_SET_TIMEUNIT` | *Producer*: Timeunit to be used in set() operation.
|=======================================================================
 
== Usage

Using `jgroups-raft` component with `enableRoleChangeEvents=true` on the consumer side of the route will capture
change in JGroups-raft role and forward them to the Camel route.
JGroups-raft consumer processes incoming messages
http://camel.apache.org/asynchronous-routing-engine.html[asynchronously].

[source,java]
----------------------------------------------
// Capture raft role changes from cluster named
// 'clusterName' and send them to Camel route.
from("jgroups-raft:clusterName?enableRoleChangeEvents=true").to("seda:queue");
----------------------------------------------

Using `jgroups-raft` component on the producer side of the route will use the body of the camel exchange (which must be a `byte[]`)
to perform a setX() operation on the raftHandle associated with the endpoint..

[source,java]
--------------------------------------------------
// perform a setX() operation to the cluster named 'clusterName' shared state machine
from("direct:start").to("jgroups-raft:clusterName");
--------------------------------------------------

== Examples

=== Receive cluster view change notifications

The snippet below demonstrates how to create the consumer endpoint
listening to the change role events. By default this option is off.

[source,java]
---------------------------------------------------------------------
...
from("jgroups-raft:clusterName?enableRoleChangeEvents=true").to(mock:mockEndpoint);
...
---------------------------------------------------------------------

=== Keeping singleton route within the cluster

The snippet below demonstrates how to keep the singleton consumer route
in the cluster of Camel Contexts. As soon as the master node dies, one
of the slaves will be elected as a new master and started. In this
particular example we want to keep singleton xref:jetty-component.adoc[jetty]
instance listening for the requests on
address` http://localhost:8080/orders`.

[source,java]
-----------------------------------------------------------------------------------------------------------------------------------------------------------------
JGroupsRaftClusterService service = new JGroupsRaftClusterService();
service.setId("raftId");
service.setRaftId("raftId");
service.setJgroupsClusterName("clusterName");
...
context.addService(service);

from("master:mycluster:jetty:http://localhost:8080/orders").to("jms:orders"); 
-----------------------------------------------------------------------------------------------------------------------------------------------------------------


include::spring-boot:partial$starter.adoc[]
