The Discovery Transport
The Discovery transport works just like the Failover transport, except that it uses a discovery agent to locate the list of uri to connect to. The Discovery transport is also used by the Fanout transport for discovering brokers to send a fanout message to.
Configuration Syntax
discovery:(discoveryAgentURI)?transportOptions
or
discovery:discoveryAgentURI
Note that to be able to use Discovery to find brokers, the brokers need to have the multicast discovery agent enabled on the broker.
To configure discovery in a Broker you should use the Xml Configuration. Here is an example of using discovery. Its basically something like the following (see the discoveryUri)
<broker name="foo">
<transportConnectors>
<transportConnector uri="tcp: discoveryUri="multicast://default"/>
</transportConnectors>
...
</broker>
Transport Options
| Option Name |
Default Value |
Description |
| reconnectDelay |
10 |
How long to wait for discovery |
| initialReconnectDelay |
10 |
How long to wait before the first reconnect attempt to a discovered url |
| maxReconnectDelay |
30000 |
The maximum amount of time we ever wait between reconnect attempts |
| useExponentialBackOff |
true |
Should an exponential backoff be used btween reconnect attempts |
| backOffMultiplier |
2 |
The exponent used in the exponential backoff attempts |
| maxReconnectAttempts |
0 |
If not 0, then this is the maximum number of reconnect attempts before an error is sent back to the client |
| group |
default |
an identifier for the group to partition multi cast traffic among collaborating peers; the group forms part of the shared identity of a discovery datagram (since 5.2) |
Example URI
 | Applying parameters to discovered transports
From 5.4, transport parameters in the URI will also be applied to discovered transports if they are prefixed with discovered.; For example, adding the discovered.connectionTimeout parameter to the URI will apply the parameter to every discovered TCP transport, even though this parameter is not a Discovery transport option. |