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10.2. Dynamic Discovery Protocol
Abstract
The dynamic discovery protocol combines reconnect logic with a discovery agent to dynamically create a list of brokers to which the client can connect.
Overview
The dynamic discovery protocol combines reconnect logic with a discovery agent to dynamically create a list of brokers to which the client can connect. The discovery protocol invokes a discovery agent in order to build up a list of broker URIs. The protocol then randomly chooses a URI from the list and attempts to establish a connection to it. If it does not succeed, or if the connection subsequently fails, a new connection is established to one of the other URIs in the list.
URI syntax
Example 10.12, “Dynamic Discovery URI” shows the syntax for a discovery URI.
Example 10.12. Dynamic Discovery URI
discovery:(DiscoveryAgentUri)?Options
DiscoveryAgentUri is URI for the discovery agent used to build up the list of available brokers. Discovery agents are described in Section 10.1, “Discovery Agents”.
The options,
?Options, are specified in the form of a query list. The discovery options are described in Table 10.1, “Dynamic Discovery Protocol Options”. You can also inject transport options as described in the section called “Setting options on the discovered transports”.
Note
If no options are required, you can drop the parentheses from the URI. The resulting URI would take the form discovery:DiscoveryAgentUri
Transport options
The discovery protocol supports the options described in Table 10.1, “Dynamic Discovery Protocol Options”.
Sample URI
Example 10.13, “Discovery Protocol URI” shows a discovery URI that uses a multicast discovery agent.
Example 10.13. Discovery Protocol URI
discovery:(multicast://default)?initialReconnectDelay=100
Setting options on the discovered transports
The list of transport options, Options, in the discovery URI can also be used to set options on the discovered transports. If you set an option not listed in the section called “Setting options on the discovered transports”, the URI parser attempts to inject the option setting into every one of the discovered endpoints.
Example 10.14, “Injecting Transport Options into a Discovered Transport” shows a discovery URI that sets the TCP
connectionTimeout option to 10 seconds.
Example 10.14. Injecting Transport Options into a Discovered Transport
discovery:(multicast://default)?connectionTimeout=10000
The 10 second timeout setting is injected into every discovered TCP endpoint.
