We are building up a new Server Client Model of Hazelcast cache in our application.
We are using Open JDK 14 Spring Boot - 2.3.2 Hazelcast - 3.12.8
Server Hazelcast COnfiguration
@Configuration
public class HazlecastConfiguration{
@Bean
public
HazelcastInstance hazlecastInstance() {
EvictionConfig evictionConfig = new EvictionConfig()
.setEvictionPolicy(EvictionPolicy.NONE)
.setMaximumSizePolicy(MaxSizePolicy.ENTRY_COUNT)
.setSize(5000);
NearCacheConfig nearCacheConfig = new NearCacheConfig()
.setInMemoryFormat(InMemoryFormat.OBJECT)
.setInvalidateOnChange(true)
.setTimeToLiveSeconds(600)
.setEvictionConfig(evictionConfig);
Config config = new Config();
config.getMapConfig("cacheMapName")
.setInMemoryFormat(InMemoryFormat.BINARY)
.setNearCacheConfig(nearCacheConfig);
NetworkConfig network = config.getNetworkConfig();
network.setPortAutoIncrement(true);
network.setPort(14571);
network.setPublicAddress(IPADDRESS+":14571");
config.setNetworkConfig(network);
config.getManagementCenterConfig().setEnabled(true);
JoinConfig join = network.getJoin();
join.getMulticastConfig().setEnabled(false);
join.getTcpIpConfig().setEnabled(true);
return Hazelcast.newHazelcastInstance(config);
}
}
Client Hazel cast Configuration
@Configuration
public class HazlecastClientConfig {
@Bean
public HazelcastInstance hazelcastInstance()
{
ClientConfig clientConfig= new ClientConfig();
ClientNetworkConfig networkConfig = clientConfig.getNetworkConfig();
networkConfig.setAddresses(IPADDRESS);
networkConfig.addAddress(IPADDRESSLIST);
clientConfig.setNetworkConfig(networkConfig);
//clientConfig.getNetworkConfig().setConnectionAttemptLimit(5);
//clientConfig.getNetworkConfig().setConnectionAttemptPeriod((int) 1.8e+6);
EvictionConfig evictionConfig = new EvictionConfig()
.setEvictionPolicy(EvictionPolicy.NONE)
.setMaximumSizePolicy(MaxSizePolicy.ENTRY_COUNT).setSize((int) 1.8e+6);
NearCacheConfig nearCacheConfig = clientConfig.getNearCacheConfig(MAPNAME);
if(nearCacheConfig == null)
{
nearCacheConfig = new NearCacheConfig()
.setName(NEARCACHENAME) .setInMemoryFormat(InMemoryFormat.OBJECT)
.setInvalidateOnChange(true)
.setEvictionConfig(evictionConfig);
}
clientConfig.addNearCacheConfig(nearCacheConfig);
ClientConnectionStrategyConfig connectionStrategyConfig =
clientConfig.getConnectionStrategyConfig();
ConnectionRetryConfig connectionRetryConfig = connectionStrategyConfig.getConnectionRetryConfig();
connectionRetryConfig.setInitialBackoffMillis(10000)
.setMaxBackoffMillis((int) 1.8e+6) .setMultiplier(5) .setJitter(0.2);
connectionRetryConfig.setFailOnMaxBackoff(false);
connectionRetryConfig.setEnabled(true);
clientConfig.setConnectionStrategyConfig(connectionStrategyConfig);
return HazelcastClient.newHazelcastClient(clientConfig);
}
}
Requirement - This configuration works perfectly if both server and client were up and running. If Server is down, Near is not working and client also forced to down. We were losing our transaction message when server is down.
We don't want to lose our client application even though the server is down. And If data is changed in server it automatically reflects in client because of .setInvalidateOnChange(true) .
We also tried https://hazelcast.com/blog/non-stop-client-with-near-cache/ . But didn't work.
When I shutdown the server I am getting below exception, Near cache is not working.
2020-09-23 13:19:56.841 INFO 17240 --- [ient_1.cluster-] c.h.c.c.nio.ClusterConnectorService : hz.client_1 [dev] [3.12.8] Trying to connect to cluster with name: dev
2020-09-23 13:19:56.841 INFO 17240 --- [ient_1.cluster-] c.h.c.c.nio.ClusterConnectorService : hz.client_1 [dev] [3.12.8] Trying to connect to [MYSERVERIPADDRESS]:14571 as owner member
2020-09-23 13:19:57.005 ERROR 17240 --- [nio-8089-exec-6] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is com.hazelcast.client.HazelcastClientOfflineException: Client is offline.] with root cause
com.hazelcast.client.HazelcastClientOfflineException: Client is offline.
at com.hazelcast.client.connection.nio.DefaultClientConnectionStrategy.beforeGetConnection(DefaultClientConnectionStrategy.java:66)~[hazelcast-client-3.12.8.jar:3.12.8]
at com.hazelcast.client.connection.nio.ClientConnectionManagerImpl.checkAllowed(ClientConnectionManagerImpl.java:300) ~[hazelcast-client-3.12.8.jar:3.12.8]
at com.hazelcast.client.connection.nio.ClientConnectionManagerImpl.getConnection(ClientConnectionManagerImpl.java:272) ~[hazelcast-client-3.12.8.jar:3.12.8]
at com.hazelcast.client.connection.nio.ClientConnectionManagerImpl.getOrTriggerConnect(ClientConnectionManagerImpl.java:263) ~[hazelcast-client-3.12.8.jar:3.12.8]
at com.hazelcast.client.spi.impl.SmartClientInvocationService.getOrTriggerConnect(SmartClientInvocationService.java:73) ~[hazelcast-client-3.12.8.jar:3.12.8]
at com.hazelcast.client.spi.impl.SmartClientInvocationService.invokeOnRandomTarget(SmartClientInvocationService.java:58) ~[hazelcast-client-3.12.8.jar:3.12.8]
at com.hazelcast.client.spi.impl.ClientInvocation.invokeOnSelection(ClientInvocation.java:167) ~[hazelcast-client-3.12.8.jar:3.12.8]
at com.hazelcast.client.spi.impl.ClientInvocation.invoke(ClientInvocation.java:146) ~[hazelcast-client-3.12.8.jar:3.12.8]
at com.hazelcast.client.spi.ClientProxy.invoke(ClientProxy.java:251) ~[hazelcast-client-3.12.8.jar:3.12.8]
at com.hazelcast.client.proxy.ClientMapProxy.values(ClientMapProxy.java:1254) ~[hazelcast-client-3.12.8.jar:3.12.8]
at com.radial.rfil.XrefUIController.getAllXrefs(XrefUIController.java:37) ~[classes/:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:878) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:792) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) ~[tomcat-embed-core-9.0.37.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.37.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1589) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) ~[na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at java.base/java.lang.Thread.run(Thread.java:832) ~[na:na]
at ------ submitted from ------.(Unknown Source) ~[na:na]
at com.hazelcast.client.spi.impl.ClientInvocationFuture.resolveAndThrowIfException(ClientInvocationFuture.java:96) ~[hazelcast-client-3.12.8.jar:3.12.8]
at com.hazelcast.client.spi.impl.ClientInvocationFuture.resolveAndThrowIfException(ClientInvocationFuture.java:33) ~[hazelcast-client-3.12.8.jar:3.12.8]
at com.hazelcast.spi.impl.AbstractInvocationFuture.get(AbstractInvocationFuture.java:155) ~[hazelcast-3.12.8.jar:3.12.8]
at com.hazelcast.client.spi.ClientProxy.invoke(ClientProxy.java:252) ~[hazelcast-client-3.12.8.jar:3.12.8]
at com.hazelcast.client.proxy.ClientMapProxy.values(ClientMapProxy.java:1254) ~[hazelcast-client-3.12.8.jar:3.12.8]
at com.radial.rfil.XrefUIController.getAllXrefs(XrefUIController.java:37) ~[classes/:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:878) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:792) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) ~[tomcat-embed-core-9.0.37.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.37.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.8.RELEASE.jar:5.2.8.RELEASE]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1589) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) ~[na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.37.jar:9.0.37]
at java.base/java.lang.Thread.run(Thread.java:832) ~[na:na]
2020-09-23 13:19:57.842 WARN 17240 --- [ient_1.cluster-] c.h.c.c.nio.ClusterConnectorService : hz.client_1 [dev] [3.12.8] Exception during initial connection to [SERVERIPADDRESS]:14571: com.hazelcast.core.HazelcastException: java.net.SocketException: Connection refused: no further information to address /10.140.127.248:14571
2020-09-23 13:19:57.842 WARN 17240 --- [ient_1.cluster-] c.h.c.c.nio.ClusterConnectorService : hz.client_1 [dev] [3.12.8] Unable to get live cluster connection, attempt 1.
2020-09-23 13:19:57.842 WARN 17240 --- [ient_1.cluster-] c.h.c.c.nio.ClusterConnectorService : hz.client_1 [dev] [3.12.8] Unable to connect to any address for cluster: dev. The following addresses were tried: [[SERVERIP]:14571]
2020-09-23 13:19:57.842 WARN 17240 --- [ient_1.cluster-] c.h.c.c.nio.ClusterConnectorService : hz.client_1 [dev] [3.12.8] Could not connect to any cluster, shutting down the client: Unable to connect to any cluster.
2020-09-23 13:19:57.843 INFO 17240 --- [clientShutdown-] com.hazelcast.core.LifecycleService : hz.client_1 [dev] [3.12.8] HazelcastClient 3.12.8 (20200625 - 35a975e) is SHUTTING_DOWN
2020-09-23 13:19:57.845 INFO 17240 --- [clientShutdown-] com.hazelcast.core.LifecycleService : hz.client_1 [dev] [3.12.8] HazelcastClient 3.12.8 (20200625 - 35a975e) is SHUTDOWN
2020-09-23 13:19:57.871 ERROR 17240 --- [nio-8089-exec-7] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is com.hazelcast.client.HazelcastClientNotActiveException: Client is not active.] with root cause
com.hazelcast.client.HazelcastClientNotActiveException: Client is not active.
at com.hazelcast.client.impl.clientside.HazelcastClientProxy.getClient(HazelcastClientProxy.java:314) ~[hazelcast-client-3.12.8.jar:3.12.8]
at com.hazelcast.client.impl.clientside.HazelcastClientProxy.getMap(HazelcastClientProxy.java:121) ~[hazelcast-client-3.12.8.jar:3.12.8]
at com.radial.rfil.XrefUIController.getAllXrefs(XrefUIController.java:29) ~[classes/:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
the blog post is for the 4.x series. https://hazelcast.com/blog/non-stop-client-with-near-cache/ .
Here is a complete example of 3.12.x series. I am adding comments inline to the example to explain the configurations and the behavior.
HazelcastInstance instance = Hazelcast.newHazelcastInstance();
ClientConfig clientConfig = new ClientConfig();
NearCacheConfig clientNearCacheConfig = new NearCacheConfig("test")
.setInMemoryFormat(InMemoryFormat.OBJECT)
.setInvalidateOnChange(false);
clientConfig.addNearCacheConfig(clientNearCacheConfig);
ClientConnectionStrategyConfig connectionStrategyConfig = clientConfig.getConnectionStrategyConfig();
//This is to get HazelcastClientOfflineExceotion when the cluster is down instead of a blocking behavior.
connectionStrategyConfig.setReconnectMode(ClientConnectionStrategyConfig.ReconnectMode.ASYNC);
ConnectionRetryConfig connectionRetryConfig = connectionStrategyConfig.getConnectionRetryConfig();
//This configuration is to make sure that the client will connect back to members when they are up.
// The client will try to connect fast at first. Then it will try to connect every 10 seconds.
// You can reduce this by making MaxBackoffMillis lower.
connectionRetryConfig.setInitialBackoffMillis(1000)
.setMaxBackoffMillis(10000).setMultiplier(2).setJitter(0.2);
//This is to make sure that client will not close ever.
connectionRetryConfig.setFailOnMaxBackoff(false);
connectionRetryConfig.setEnabled(true);
clientConfig.setConnectionStrategyConfig(connectionStrategyConfig);
HazelcastInstance client = HazelcastClient.newHazelcastClient(clientConfig);
IMap<Object, Object> map = client.getMap("test");
//populate the map with 2000 items
for (int i = 0; i < 2000; i++) {
map.put(i, i);
}
//populates the client nearcache for first 1000 items for demonstration purposes
for (int i = 0; i < 1000; i++) {
map.get(i);
}
//shutting down the cluster to demonstrate near cache works without the cluster
instance.shutdown();
Random random = new Random();
//Returns from nearcache without throwing exception
System.out.println("get a cached entry " + map.get(random.nextInt(1000)));
try {
// Try to get a non cached key, should result with exception without blocking the thread
map.get(10001);
} catch (HazelcastClientOfflineException e) {
//Here you can fall back to plan B when the key is not in the near cache.
System.out.println("Get exception " + e);
}
//Alternatively `getAll(keys)` can be called with all the keys that we are sure in the nearcache
HashSet<Object> objects = new HashSet<>();
for (int i = 0; i < 1000; i++) {
objects.add(i);
}
//Returns from nearcache without throwing exception.
System.out.println("Size should be 1000 : " + map.getAll(objects).size());
Note that HazelcastClientOfflineException is expected if your key is not in the near cache yet when the clusters are down. So your implementation should actively wait for HazelcastClientOfflineException and fallback to plan B when the data is not available on the cache.