com.netflix.loadbalancer

Class LoadBalancerExecutor

java.lang.Object

com.netflix.loadbalancer.LoadBalancerContext

com.netflix.loadbalancer.LoadBalancerExecutor

All Implemented Interfaces:

com.netflix.client.IClientConfigAware

Direct Known Subclasses:

AbstractLoadBalancerAwareClient

public class LoadBalancerExecutor
extends LoadBalancerContext

Provides APIs to execute and retry tasks on a server chosen by the associated load balancer. With appropriate RetryHandler, it will also retry on one or more different servers.

Field Summary

Fields inherited from class com.netflix.loadbalancer.LoadBalancerContext

clientName, defaultRetryHandler, maxAutoRetries, maxAutoRetriesNextServer, okToRetryOnAllOperations, vipAddresses

Constructor Summary

Constructors

Constructor and Description
LoadBalancerExecutor(ILoadBalancer lb)
LoadBalancerExecutor(ILoadBalancer lb, com.netflix.client.config.IClientConfig clientConfig)
LoadBalancerExecutor(ILoadBalancer lb, com.netflix.client.config.IClientConfig clientConfig, com.netflix.client.RetryHandler defaultRetryHandler)

Method Summary

Methods

Modifier and Type	Method and Description
protected <T> T	create(LoadBalancerCommand<T> command, java.net.URI loadBalancerURI, com.netflix.client.RetryHandler retryHandler, java.lang.Object loadBalancerKey) Execute a task on a server chosen by load balancer with possible retries.
<T> rx.Observable<T>	create(LoadBalancerObservableCommand<T> observableCommand) Create an Observable that once subscribed execute network call asynchronously with a server chosen by load balancer.
<T> rx.Observable<T>	create(LoadBalancerObservableCommand<T> observableCommand, com.netflix.client.RetryHandler retryHandler) Create an Observable that once subscribed execute network call asynchronously with a server chosen by load balancer.
protected <T> rx.Observable<T>	create(LoadBalancerObservableCommand<T> observableCommand, java.net.URI loadBalancerURI, com.netflix.client.RetryHandler retryHandler, java.lang.Object loadBalancerKey) Create an Observable that once subscribed execute network call asynchronously with a server chosen by load balancer.
<T> T	execute(LoadBalancerCommand<T> command) Execute a task on a server chosen by load balancer with possible retries.
<T> T	execute(LoadBalancerCommand<T> command, com.netflix.client.RetryHandler retryHandler) Execute a task on a server chosen by load balancer with possible retries.
<T> rx.Observable<T>	retryWithSameServer(Server server, rx.Observable<T> forServer, com.netflix.client.RetryHandler errorHandler) Gets the Observable that represents the result of executing on a server, after possible retries as dictated by RetryHandler.

Methods inherited from class com.netflix.loadbalancer.LoadBalancerContext

deriveHostAndPortFromVipAddress, deriveSchemeAndPortFromPartialUri, generateNIWSException, getClientName, getDeepestCause, getDefaultPortFromScheme, getExecuteTracer, getLoadBalancer, getMaxAutoRetries, getMaxAutoRetriesNextServer, getNumberRetriesOnSameServer, getRetriesNextServer, getRetryHandler, getServerFromLoadBalancer, getServerStats, handleSameServerRetry, initWithNiwsConfig, isOkToRetryOnAllOperations, noteError, noteOpenConnection, noteRequestCompletion, noteRequestCompletion, noteResponse, reconstructURIWithServer, setLoadBalancer, setMaxAutoRetries, setMaxAutoRetriesNextServer, setOkToRetryOnAllOperations, setRetryHandler

Methods inherited from class java.lang.Object

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

Constructor Detail

LoadBalancerExecutor

public LoadBalancerExecutor(ILoadBalancer lb)

LoadBalancerExecutor

public LoadBalancerExecutor(ILoadBalancer lb,
                    com.netflix.client.config.IClientConfig clientConfig)

LoadBalancerExecutor

public LoadBalancerExecutor(ILoadBalancer lb,
                    com.netflix.client.config.IClientConfig clientConfig,
                    com.netflix.client.RetryHandler defaultRetryHandler)

Method Detail

execute

public <T> T execute(LoadBalancerCommand<T> command,
            com.netflix.client.RetryHandler retryHandler)
          throws java.lang.Exception

Execute a task on a server chosen by load balancer with possible retries. If there are any errors that are indicated as retriable by the RetryHandler, they will be consumed internally. If number of retries has exceeds the maximal allowed, a final error will be thrown. Otherwise, the first successful result during execution and retries will be returned.

Parameters:

command - interface that provides the logic to execute network call synchronously with a given Server

Throws:

java.lang.Exception - If any exception happens in the exception

execute

public <T> T execute(LoadBalancerCommand<T> command)
          throws java.lang.Exception

Execute a task on a server chosen by load balancer with possible retries. If there are any errors that are indicated as retriable by the RetryHandler, they will be consumed internally. If number of retries has exceeds the maximal allowed, a final error will be thrown. Otherwise, the first successful result during execution and retries will be returned.

Parameters:

command - interface that provides the logic to execute network call synchronously with a given Server

Throws:

java.lang.Exception - If any exception happens in the exception

create

protected <T> T create(LoadBalancerCommand<T> command,
           @Nullable
           java.net.URI loadBalancerURI,
           @Nullable
           com.netflix.client.RetryHandler retryHandler,
           @Nullable
           java.lang.Object loadBalancerKey)
            throws java.lang.Exception

Execute a task on a server chosen by load balancer with possible retries. If there are any errors that are indicated as retriable by the RetryHandler, they will be consumed internally. If number of retries has exceeds the maximal allowed, a final error will be thrown. Otherwise, the first successful result during execution and retries will be returned.

Parameters:

command - interface that provides the logic to execute network call synchronously with a given Server

loadBalancerURI - An optional URI that may contain a real host name and port to use as a fallback to the LoadBalancerExecutor if it does not have a load balancer or cannot find a server from its server list. For example, the URI contains "www.google.com:80" will force the LoadBalancerExecutor to use www.google.com:80 as the actual server to carry out the retry execution. See LoadBalancerContext.getServerFromLoadBalancer(URI, Object)

retryHandler - an optional handler to determine the retry logic of the LoadBalancerExecutor. If null, the default RetryHandler of this LoadBalancerExecutor will be used.

loadBalancerKey - An optional key passed to the load balancer to determine which server to return.

Throws:

java.lang.Exception - If any exception happens in the exception

create

public <T> rx.Observable<T> create(LoadBalancerObservableCommand<T> observableCommand,
                          @Nullable
                          com.netflix.client.RetryHandler retryHandler)

Create an Observable that once subscribed execute network call asynchronously with a server chosen by load balancer. If there are any errors that are indicated as retriable by the RetryHandler, they will be consumed internally by the function and will not be observed by the Observer subscribed to the returned Observable. If number of retries has exceeds the maximal allowed, a final error will be emitted by the returned Observable. Otherwise, the first successful result during execution and retries will be emitted.

Parameters:

observableCommand - interface that provides the logic to execute network call asynchronously with a given Server

retryHandler - an optional handler to determine the retry logic of the LoadBalancerExecutor. If null, the default RetryHandler of this LoadBalancerExecutor will be used.

create

public <T> rx.Observable<T> create(LoadBalancerObservableCommand<T> observableCommand)

Create an Observable that once subscribed execute network call asynchronously with a server chosen by load balancer. If there are any errors that are indicated as retriable by the RetryHandler, they will be consumed internally by the function and will not be observed by the Observer subscribed to the returned Observable. If number of retries has exceeds the maximal allowed, a final error will be emitted by the returned Observable. Otherwise, the first successful result during execution and retries will be emitted.

Parameters:

observableCommand - interface that provides the logic to execute network call synchronously with a given Server

create

protected <T> rx.Observable<T> create(LoadBalancerObservableCommand<T> observableCommand,
                          @Nullable
                          java.net.URI loadBalancerURI,
                          @Nullable
                          com.netflix.client.RetryHandler retryHandler,
                          @Nullable
                          java.lang.Object loadBalancerKey)

Create an Observable that once subscribed execute network call asynchronously with a server chosen by load balancer. If there are any errors that are indicated as retriable by the RetryHandler, they will be consumed internally by the function and will not be observed by the Observer subscribed to the returned Observable. If number of retries has exceeds the maximal allowed, a final error will be emitted by the returned Observable. Otherwise, the first successful result during execution and retries will be emitted.

Parameters:

observableCommand - interface that provides the logic to execute network call asynchronously with a given Server

loadBalancerURI - An optional URI that may contain a real host name and port to be used by LoadBalancerExecutor if it does not have a load balancer or cannot find a server from its server list. For example, the URI contains "www.google.com:80" will force the LoadBalancerExecutor to use www.google.com:80 as the actual server to carry out the retry execution. See LoadBalancerContext.getServerFromLoadBalancer(URI, Object)

retryHandler - an optional handler to determine the retry logic of the LoadBalancerExecutor. If null, the default RetryHandler of this LoadBalancerExecutor will be used.

loadBalancerKey - An optional key passed to the load balancer to determine which server to return.

retryWithSameServer

public <T> rx.Observable<T> retryWithSameServer(Server server,
                                       rx.Observable<T> forServer,
                                       com.netflix.client.RetryHandler errorHandler)

Gets the Observable that represents the result of executing on a server, after possible retries as dictated by RetryHandler. During retry, any errors that are retriable are consumed by the function and will not be observed by the external Observer. If number of retries exceeds the maximal retries allowed on one server, a final error will be emitted by the returned Observable.

Parameters:

forServer - A lazy Observable that does not start execution until it is subscribed to