Analysis of spring-cloud-ribbon principle: several core classes of ribbon

Ribbon is a client load balancer that provides great control over the behavior of HTTP and TCP clients. Feign has used Ribbon by default (reference article)

1. Let’s take a look at several core classes of ribbon

1, IClientConfig Default implementation classDefaultClientConfigImpl , mainly used to configure the relevant attribute configuration of the ribbon client

2, ServerListUpdaterDefault implementation class PollingServerListUpdater, mainly responsible for dynamically updating the server list

• After the start method is called, a scheduled task will be started, with a delay of 1s to start execution, and it will be executed periodically every 30s time interval

• Periodic time interval You can set the

  start method by
ribbon.ServerListRefreshInterval=1000
or
• ribbonClientName.ribbon.ServerListRefreshInterval=1000

  . ##DynamicServerListLoadBalancerExecute the call during initialization

3,

ServerListGet the server list

• Default implementation class

  ConfigurationBasedServerList, the default is to get the server list from the configuration file, configure it like this [ribbonClinetName].ribbon.listOfServers=xxx,xxx

• ConsulServerListIntroduces the implementation class of consul for service discovery, which is mainly responsible for obtaining the server list of the registration center

  
  

  Remarks: You can extend your own# through configuration ##ServerList

  Implementation, like this: [ribbonClient].ribbon.NIWSServerListClassName=Class name

  ##4、
ServerListFilter

Server list Filter

Default implementation class

ZonePreferenceServerListFilter
• Mainly filters the server list based on partitions

HealthServiceServerListFilter
• Introduce the implementation class of consul service discovery, which is mainly responsible for filtering the list of servers that pass the consul health check (all server lists will be obtained in ConsulServerList, including servers that fail the health check)

  Note: You can extend your own
  ServerList

  implementation through configuration, like this

  [ribbonClient].ribbon.NIWSServerListFilterClassName=Class name

  5,
IPing

Check whether the server or

default implementation

DummyPing
• , this is a false detection, always returns true

ConsulPing
• , introduces the implementation class of consul service discovery, mainly based on the checks parameter returned by consul to determine whether the server is alive, and

  HealthServiceServerListFilter The filtering judgment is the same

  Note: You can extend your own
  ServerList

  implementation through configuration, like this:

  [ribbonClient].ribbon .NFLoadBalancerPingClassName=Class name

  6、
IRule

Load balancing selector

Default implementation

ZoneAvoidanceRule
• , which combines the performance of the zone where the server is located and the availability of the server to select server

RandomRule
• : randomly select a server

RoundRobinRule
• : RoundRobin mode polls the selected server

RetryRule
• : On-machine retry mechanism for the selected load balancing policy.

WeightedResponseTimeRule
• : Assign a weight based on the response time. The longer the response time, the smaller the weight, and the lower the possibility of being selected.

AvailabilityFilteringRule
• : Filter out those back-end servers that are marked as circuit tripped because of persistent connection failures, and filter out those back-end servers with high concurrency ( active connections exceeds the configured threshold)

BestAvailableRule
• : Select a server with the smallest concurrent requests

7, ILoadBalancer

Load balancing master controller, default implementation class

ZoneAwareLoadBalancer, which starts the entire load balancing client

You can extend your own

ServerList
• implementation through configuration, like this:

  [ribbonClient].ribbon.NFLoadBalancerClassName=Class name

  Load balancer startup sequence diagram:
  

• During initialization, a scheduled task will be initialized first, which will be executed every 30 seconds. The cache will store all the instance lists allServerList obtained from the registration center and the instance list upServerList that have been successfully pinged. However, during load balancing The list I got is allServerList instead of upServerList. I don’t understand the meaning of this ping

• Start a scheduled task to pull the service list from the registration center regularly and execute it every 30 seconds

• Initialize to obtain the service list. The pulled service list is filtered by ServiceFilter and stored in the cache.

When the client initiates a call, it will Call the chooseServer method of ILoadBalancer to select an instance and return it to the caller according to the load balancing algorithm of IRule.

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WPF 4 Ribbon Development Quick Access Toolbar )

SharePoint 2013 Hide the page’s Ribbon, menu and other non-content elements

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