org.axonframework.springcloud.commandhandling

Class SpringCloudHttpBackupCommandRouter

java.lang.Object

org.axonframework.springcloud.commandhandling.SpringCloudCommandRouter

org.axonframework.springcloud.commandhandling.SpringCloudHttpBackupCommandRouter

All Implemented Interfaces:

CommandRouter

@RestController
 @RequestMapping(value="${axon.distributed.spring-cloud.fallback-url:/message-routing-information}")
public class SpringCloudHttpBackupCommandRouter
extends SpringCloudCommandRouter

Implementation of the SpringCloudCommandRouter which has a backup mechanism to provide Message Routing Information for other nodes and to retrieve Message Routing Information from other Axon nodes.

It is annotated with the RestController and contains the GetMapping annotated getLocalMessageRoutingInformation() function to have a queryable place to retrieve this node its Message Routing Information. The default endpoint for this is "/message-routing-information". To configure this endpoint the "axon.distributed.spring-cloud.fallback-url" application property should be adjusted.

For retrieving the Message Routing Information from other Axon nodes, it uses a RestTemplate to request Message Routing Information through an override of the getMessageRoutingInformation(ServiceInstance) function.

Since:

3.1

Author:

Steven van Beelen

Field Summary

Fields inherited from class org.axonframework.springcloud.commandhandling.SpringCloudCommandRouter

serializer

Constructor Summary

Constructors

Constructor and Description
SpringCloudHttpBackupCommandRouter(org.springframework.cloud.client.discovery.DiscoveryClient discoveryClient, org.springframework.cloud.client.serviceregistry.Registration localServiceInstance, RoutingStrategy routingStrategy, Predicate<org.springframework.cloud.client.ServiceInstance> serviceInstanceFilter, ConsistentHashChangeListener consistentHashChangeListener, org.springframework.web.client.RestTemplate restTemplate, String messageRoutingInformationEndpoint) Initialize a CommandRouter with the given DiscoveryClient to update its own membership as a CommandRouter and to create its own awareness of available nodes to send commands to in a ConsistentHash.
SpringCloudHttpBackupCommandRouter(org.springframework.cloud.client.discovery.DiscoveryClient discoveryClient, org.springframework.cloud.client.serviceregistry.Registration localServiceInstance, RoutingStrategy routingStrategy, Predicate<org.springframework.cloud.client.ServiceInstance> serviceInstanceFilter, org.springframework.web.client.RestTemplate restTemplate, String messageRoutingInformationEndpoint) Initialize a CommandRouter with the given DiscoveryClient to update its own membership as a CommandRouter and to create its own awareness of available nodes to send commands to in a ConsistentHash.
SpringCloudHttpBackupCommandRouter(org.springframework.cloud.client.discovery.DiscoveryClient discoveryClient, org.springframework.cloud.client.serviceregistry.Registration localServiceInstance, RoutingStrategy routingStrategy, org.springframework.web.client.RestTemplate restTemplate, String messageRoutingInformationEndpoint) Initialize a CommandRouter with the given DiscoveryClient to update its own membership as a CommandRouter and to create its own awareness of available nodes to send commands to in a ConsistentHash.

Method Summary

Modifier and Type	Method and Description
MessageRoutingInformation	getLocalMessageRoutingInformation() Get the local MessageRoutingInformation, thus the MessageRoutingInformation of the node this CommandRouter is a part of.
protected Optional<MessageRoutingInformation>	getMessageRoutingInformation(org.springframework.cloud.client.ServiceInstance serviceInstance) Retrieve the MessageRoutingInformation of the provided serviceInstance.
void	updateMembership(int loadFactor, Predicate<? super CommandMessage<?>> commandFilter) Updates the load factor and capabilities of this member representing the current endpoint if the implementation allows memberships to be updated dynamically.

Methods inherited from class org.axonframework.springcloud.commandhandling.SpringCloudCommandRouter

buildMember, findDestination, resetLocalMembership, serviceInstanceMetadataContainsMessageRoutingInformation, updateMemberships

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SpringCloudHttpBackupCommandRouter

@Autowired
public SpringCloudHttpBackupCommandRouter(org.springframework.cloud.client.discovery.DiscoveryClient discoveryClient,
                                                      org.springframework.cloud.client.serviceregistry.Registration localServiceInstance,
                                                      RoutingStrategy routingStrategy,
                                                      org.springframework.web.client.RestTemplate restTemplate,
                                                      @Value(value="${axon.distributed.spring-cloud.fallback-url:/message-routing-information}")
                                                      String messageRoutingInformationEndpoint)

Initialize a CommandRouter with the given DiscoveryClient to update its own membership as a CommandRouter and to create its own awareness of available nodes to send commands to in a ConsistentHash. The routingStrategy is used to define the key based on which Command Messages are routed to their respective handler nodes. The RestTemplate is used as a backup mechanism to request another member's MessageRoutingInformation with. Uses a default Predicate<ServiceInstance> filter function which allows any ServiceInstance through the update membership process. Uses a default NoOp ConsistentHashChangeListener which is called if the ConsistentHash changed.

Parameters:

discoveryClient - The DiscoveryClient used to discovery and notify other nodes

localServiceInstance - A Registration representing the local Service Instance of this application. Necessary to differentiate between other instances for correct message routing

routingStrategy - The strategy for routing Commands to a Node

restTemplate - The RestTemplate used to request another member's MessageRoutingInformation with.

messageRoutingInformationEndpoint - The endpoint where to retrieve the another nodes message routing information from

SpringCloudHttpBackupCommandRouter

public SpringCloudHttpBackupCommandRouter(org.springframework.cloud.client.discovery.DiscoveryClient discoveryClient,
                                          org.springframework.cloud.client.serviceregistry.Registration localServiceInstance,
                                          RoutingStrategy routingStrategy,
                                          Predicate<org.springframework.cloud.client.ServiceInstance> serviceInstanceFilter,
                                          org.springframework.web.client.RestTemplate restTemplate,
                                          String messageRoutingInformationEndpoint)

Initialize a CommandRouter with the given DiscoveryClient to update its own membership as a CommandRouter and to create its own awareness of available nodes to send commands to in a ConsistentHash. The routingStrategy is used to define the key based on which Command Messages are routed to their respective handler nodes. A Predicate<ServiceInstance> to filter a ServiceInstance from the membership update loop. The RestTemplate is used as a backup mechanism to request another member's MessageRoutingInformation with. * Uses a default NoOp ConsistentHashChangeListener which is called if the ConsistentHash changed.

Parameters:

discoveryClient - The DiscoveryClient used to discovery and notify other nodes

localServiceInstance - A Registration representing the local Service Instance of this application. Necessary to differentiate between other instances for correct message routing

routingStrategy - The strategy for routing Commands to a Node

serviceInstanceFilter - The Predicate<ServiceInstance> used to filter

restTemplate - The RestTemplate used to request another member's MessageRoutingInformation with.

messageRoutingInformationEndpoint - The endpoint where to retrieve the another nodes message routing information from

SpringCloudHttpBackupCommandRouter

public SpringCloudHttpBackupCommandRouter(org.springframework.cloud.client.discovery.DiscoveryClient discoveryClient,
                                          org.springframework.cloud.client.serviceregistry.Registration localServiceInstance,
                                          RoutingStrategy routingStrategy,
                                          Predicate<org.springframework.cloud.client.ServiceInstance> serviceInstanceFilter,
                                          ConsistentHashChangeListener consistentHashChangeListener,
                                          org.springframework.web.client.RestTemplate restTemplate,
                                          String messageRoutingInformationEndpoint)

Initialize a CommandRouter with the given DiscoveryClient to update its own membership as a CommandRouter and to create its own awareness of available nodes to send commands to in a ConsistentHash. The routingStrategy is used to define the key based on which Command Messages are routed to their respective handler nodes. A Predicate<ServiceInstance> to filter a ServiceInstance from the membership update loop. The given consistentHashChangeListener is notified about changes in membership that affect routing of messages. The RestTemplate is used as a backup mechanism to request another member's MessageRoutingInformation with.

Parameters:

discoveryClient - The DiscoveryClient used to discovery and notify other nodes

localServiceInstance - A Registration representing the local Service Instance of this application. Necessary to differentiate between other instances for correct message routing

routingStrategy - The strategy for routing Commands to a Node

serviceInstanceFilter - The Predicate<ServiceInstance> used to filter

consistentHashChangeListener - The callback to invoke when there is a change in the ConsistentHash

restTemplate - The RestTemplate used to request another member's MessageRoutingInformation with.

messageRoutingInformationEndpoint - The endpoint where to retrieve the another nodes message routing information from

Method Detail

updateMembership

public void updateMembership(int loadFactor,
                             Predicate<? super CommandMessage<?>> commandFilter)

Description copied from interface: CommandRouter

Updates the load factor and capabilities of this member representing the current endpoint if the implementation allows memberships to be updated dynamically.

Specified by:

updateMembership in interface CommandRouter

Overrides:

updateMembership in class SpringCloudCommandRouter

Parameters:

loadFactor - the new load factor of the member for this endpoint

commandFilter - the new capabilities of the member for this endpoint

getLocalMessageRoutingInformation

@GetMapping
public MessageRoutingInformation getLocalMessageRoutingInformation()

Get the local MessageRoutingInformation, thus the MessageRoutingInformation of the node this CommandRouter is a part of. Can either be called directly or through a GET operation on the specified messageRoutingInformationEndpoint of this node.

Returns:

The MessageRoutingInformation if the node this CommandRouter implementation is part of.

getMessageRoutingInformation

protected Optional<MessageRoutingInformation> getMessageRoutingInformation(org.springframework.cloud.client.ServiceInstance serviceInstance)

Description copied from class: SpringCloudCommandRouter

Retrieve the MessageRoutingInformation of the provided serviceInstance. If the MessageRoutingInformation could not be found, an Optional.empty() will be returned. Otherwise the MessageRoutingInformation will be contained in the Optional.

Overrides:

getMessageRoutingInformation in class SpringCloudCommandRouter

Parameters:

serviceInstance - A ServiceInstance to retrieve MessageRoutingInformation from.

Returns:

an Optional of type MessageRoutingInformation, containing the corresponding MessageRoutingInformation for the given serviceInstance if it could be retrieved.