Package org.apache.druid.rpc

Class ServiceClientImpl

java.lang.Object

org.apache.druid.rpc.ServiceClientImpl

All Implemented Interfaces:

ServiceClient

public class ServiceClientImpl
extends Object
implements ServiceClient

Production implementation of ServiceClient.

Field Summary

Fields inherited from interface org.apache.druid.rpc.ServiceClient

MAX_REDIRECTS

Constructor Summary

Constructors

Constructor	Description
ServiceClientImpl(String serviceName, HttpClient httpClient, ServiceLocator serviceLocator, ServiceRetryPolicy retryPolicy, ScheduledExecutorService connectExec)

Method Summary

Modifier and Type	Method	Description
<IntermediateType, FinalType> com.google.common.util.concurrent.ListenableFuture<FinalType>	asyncRequest(RequestBuilder requestBuilder, HttpResponseHandler<IntermediateType,FinalType> handler)	Perform a request asynchronously.
static long	computeBackoffMs(ServiceRetryPolicy retryPolicy, long attemptNumber)
ServiceClientImpl	withRetryPolicy(ServiceRetryPolicy newRetryPolicy)	Returns a copy of this client with a different ServiceRetryPolicy.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.druid.rpc.ServiceClient

request

Constructor Details

ServiceClientImpl

public ServiceClientImpl(String serviceName,
 HttpClient httpClient,
 ServiceLocator serviceLocator,
 ServiceRetryPolicy retryPolicy,
 ScheduledExecutorService connectExec)

Method Details

asyncRequest

public <IntermediateType,
FinalType>
com.google.common.util.concurrent.ListenableFuture<FinalType> asyncRequest(RequestBuilder requestBuilder,
 HttpResponseHandler<IntermediateType,FinalType> handler)

Description copied from interface: ServiceClient

Perform a request asynchronously. Unlike HttpClient.go(org.apache.druid.java.util.http.client.Request, org.apache.druid.java.util.http.client.response.HttpResponseHandler<Intermediate, Final>), the provided "handler" is only used for 2xx responses. Response codes 1xx, 4xx, and 5xx are retried with backoff according to the client's ServiceRetryPolicy. If attempts are exhausted, the future will fail with RpcException containing the most recently encountered error. Redirects from 3xx responses are followed up to a chain length of ServiceClient.MAX_REDIRECTS and do not consume attempts. Redirects are validated against the targets returned by ServiceLocator: the client will only follow redirects to targets that appear in ServiceLocations. If the client encounters a redirect to an unknown target, or if a redirect loop or self-redirect is detected, it is treated as an unavailable service and an attempt is consumed. If the service is unavailable at the time an attempt is made, the client will automatically retry based on ServiceRetryPolicy.retryNotAvailable(). If true, an attempt is consumed and the client will try to locate the service again on the next attempt. If false, the call immediately returns ServiceNotAvailableException. If an exception occurs midstream after an OK HTTP response (2xx) then the behavior depends on the handler. If the handler has not yet returned a finished object, the service client will automatically retry based on the provided ServiceRetryPolicy. On the other hand, if the handler has returned a finished object, the service client will not retry. Behavior in this case is up to the caller, who will have already received the finished object as the future's resolved value. Resolves to HttpResponseException if the final attempt failed due to a non-OK HTTP server response. Resolves to ServiceNotAvailableException if the final attempt failed because the service was not available (i.e. if the locator returned an empty set of locations). Resolves to ServiceClosedException if the final attempt failed because the service was closed. This is different from not available: generally, "not available" is a temporary condition whereas "closed" is a permanent condition.

Specified by:

asyncRequest in interface ServiceClient

withRetryPolicy

public ServiceClientImpl withRetryPolicy(ServiceRetryPolicy newRetryPolicy)

Description copied from interface: ServiceClient

Returns a copy of this client with a different ServiceRetryPolicy.

Specified by:

withRetryPolicy in interface ServiceClient

computeBackoffMs

public static long computeBackoffMs(ServiceRetryPolicy retryPolicy,
 long attemptNumber)