Windows RPC access denied even with RPC_C_AUTHN_NONE - c

I have this error while trying to connect my RPC client to my RPC server:
Error occurred:5
Some googling showed me the meaning of this error: access denied.
The trouble does not come from the firewall.
Here is the server part, where I specify RPC_C_AUTHN_NONE to let everyone connect:
RPC_STATUS status;
printf("RPC Server Starting...\n");
status = RpcServerUseProtseqEp(
(unsigned char *)"ncacn_ip_tcp",
RPC_C_PROTSEQ_MAX_REQS_DEFAULT,
(unsigned char *)"9191",
RPC_C_AUTHN_NONE);
if (status) { printf("Error:%d\n", status); exit(status); }
printf("RPC Server Configured\n");
Here is the client part raising the error:
RpcTryExcept {
unsigned char szMsg[] = "Client: I can RPC now!\n";
md5(szMsg);
} RpcExcept(1) {
printf("Error occurred:%d\n", RpcExceptionCode());
}
RpcEndExcept
How do I correct this issue, in order to let any RPC client connects?
And in the same order, do you know a good RPC documentation for Windows RPC authentication?
Many thanks!

I have spent some time figuring why this happened, and I provide this answer as I found a solution, in order to help those who might encounter this trouble:
By default, RPC connection are only granted to authenticated clients. This can be changed by editing a registry entry or applying a GPO to disable restrictions for unauthenticated users as specified here.

Related

Google Cloud Run pubsub pull listener app fails to start

I'm testing pubsub "pull" subscriber on Cloud Run using just listener part of this sample java code (SubscribeAsyncExample...reworked slightly to fit in my SpringBoot app):
https://cloud.google.com/pubsub/docs/quickstart-client-libraries#java_1
It fails to startup during deploy...but while it's trying to start, it does pull items from the pubsub queue. Originally, I had an HTTP "push" receiver (a #RestController) on a different pubsub topic and that worked fine. Any suggestions? I'm new to Cloud Run. Thanks.
Deploying...
Creating Revision... Cloud Run error: Container failed to start. Failed to start and then listen on the port defined
by the PORT environment variable. Logs for this revision might contain more information....failed
Deployment failed
In logs:
2020-08-11 18:43:22.688 INFO 1 --- [ main] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 4606 ms
2020-08-11T18:43:25.287759Z Listening for messages on projects/ce-cxmo-dev/subscriptions/AndySubscriptionPull:
2020-08-11T18:43:25.351650801Z Container Sandbox: Unsupported syscall setsockopt(0x18,0x29,0x31,0x3eca02dfd974,0x4,0x28). It is very likely that you can safely ignore this message and that this is not the cause of any error you might be troubleshooting. Please, refer to https://gvisor.dev/c/linux/amd64/setsockopt for more information.
2020-08-11T18:43:25.351770555Z Container Sandbox: Unsupported syscall setsockopt(0x18,0x29,0x12,0x3eca02dfd97c,0x4,0x28). It is very likely that you can safely ignore this message and that this is not the cause of any error you might be troubleshooting. Please, refer to https://gvisor.dev/c/linux/amd64/setsockopt for more information.
2020-08-11 18:43:25.680 WARN 1 --- [ault-executor-0] i.g.n.s.i.n.u.internal.MacAddressUtil : Failed to find a usable hardware address from the network interfaces; using random bytes: ae:2c:fb:e7:92:9c:2b:24
2020-08-11T18:45:36.282714Z Id: 1421389098497572
2020-08-11T18:45:36.282763Z Data: We be pub-sub'n in pull mode2!!
Nothing else after this and the app stops running.
#Component
public class AndyTopicPullRecv {
public AndyTopicPullRecv()
{
subscribeAsyncExample("ce-cxmo-dev", "AndySubscriptionPull");
}
public static void subscribeAsyncExample(String projectId, String subscriptionId) {
ProjectSubscriptionName subscriptionName =
ProjectSubscriptionName.of(projectId, subscriptionId);
// Instantiate an asynchronous message receiver.
MessageReceiver receiver =
(PubsubMessage message, AckReplyConsumer consumer) -> {
// Handle incoming message, then ack the received message.
System.out.println("Id: " + message.getMessageId());
System.out.println("Data: " + message.getData().toStringUtf8());
consumer.ack();
};
Subscriber subscriber = null;
try {
subscriber = Subscriber.newBuilder(subscriptionName, receiver).build();
// Start the subscriber.
subscriber.startAsync().awaitRunning();
System.out.printf("Listening for messages on %s:\n", subscriptionName.toString());
// Allow the subscriber to run for 30s unless an unrecoverable error occurs.
// subscriber.awaitTerminated(30, TimeUnit.SECONDS);
subscriber.awaitTerminated();
System.out.printf("Async subscribe terminated on %s:\n", subscriptionName.toString());
// } catch (TimeoutException timeoutException) {
} catch (Exception e) {
// Shut down the subscriber after 30s. Stop receiving messages.
subscriber.stopAsync();
System.out.printf("Async subscriber exception: " + e);
}
}
}
Kolban question is very important!! With the shared code, I would like to say "No". The Cloud Run contract is clear:
Your service must answer to HTTP request. Out of request, you pay nothing and no CPU is dedicated to your instance (the instance is like a daemon when no request is processing)
Your service must be stateless (not your case here, I won't take time on this)
If you want to pull your PubSub subscription, create an endpoint in your code with a Rest controller. While you are processing this request, run your pull mechanism and process messages.
This endpoint can be called by Cloud Scheduler regularly to keep the process up.
Be careful, you have a max request processing timeout at 15 minutes (today, subject to change in a near future). So, you can't run your process more than 15 minutes. Make it resilient to fail and set your scheduler to call your service every 15 minutes

What is a proper HTTP status code that server returns when it limits total number of connections?

I have made a simple HTTP server that listens to socket connections. The server code limits total number of connections that it can hold simultaneously.
So, I have these lines:
do {
new_fd = accept(lfd, NULL, NULL);
nfds += 1;
...
if(nfds + 1 > ntotal){ // connection limit exceeded
set_headers( new_fd, /* HTTP status code here */ );
/* close socket after error had been sent */
}
}while(1);
In this situation I'm interested with HTTP status code that server should send before closing socket.
From this link, it appears 503 is the appropriate HTTP status code to send for an overloaded server.
10.5.4 503 Service Unavailable
The server is currently unable to handle the request due to a
temporary overloading or maintenance of the server. The implication is
that this is a temporary condition which will be alleviated after some
delay. If known, the length of the delay MAY be indicated in a
Retry-After header. If no Retry-After is given, the client SHOULD
handle the response as it would for a 500 response.
Note: The existence of the 503 status code does not imply that a
server must use it when becoming overloaded. Some servers may wish
to simply refuse the connection.
(bold emphasis mine)

Microsoft RPC SChannel not encrypted

I have been struggling to get a secure RPC client/server using Microsoft RPC. I am not using COM, just straight C.
I have created a Root CA certificate and created a certificate signed by this cert for the server. The certs are installed into cert stores.
RPC works fine unencrypted and it will even work with SCHANNEL setup, just not encrypted.
ServerCode:
RpcServerUseProtseqEpW(
L"ncacn_ip_tcp",
RPC_C_LISTEN_MAX_CALLS_DEFAULT,
port,
NULL);
CertOpenStore(
CERT_STORE_PROV_SYSTEM,
0,
(HCRYPTPROV)NULL,
CERT_SYSTEM_STORE_LOCAL_MACHINE | CERT_STORE_READONLY_FLAG,
L"MY")
CertFindCertificateInStore(
hStore,
X509_ASN_ENCODING|PKCS_7_ASAN_ENCODING,
CERT_FIND_SUBJEECT_STR,
subject,
NULL);
RpcCertGeneratePrincipalNameW(
ccert_ctx_server,
RPC_C_FULL_CERT_CHAIN,
serverPrincName);
schannel.dwVersion = SCHANNEL_CRED_VERSION;
schannel.cCreds = 1;
schannel.paCred = &ccert_ctx_server;
RpcServerRegisterAuthInfoW(
serverPrincName,
RPC_C_AUTHN_GSS_SCHANNEL,
NULL,
&schannel);
RpcServerRegisterIf2(
h_v1_ifspec,
NULL,
NULL,
RPC_IF_ALLOW_CALLBACKS_WITH_NO_AUTH // seems to be required by SCHANNEL
RPC_C_LISTEN_MAX_CALLS_DEFAULT,
(unsigned)-1,
SecurityCallback); SecurityCallback returns RPC_S_OK
Client Code:
RpcStringBindingComposeW(
NULL,
L"ncacn_ip_tcp",
address,
port,
NULL,
&stringBinding);
RpcBindingFronStringBindingW(
stringBinding,
hBind);
CertOpenStore(
CERT_STORE_PROV_SYSTEM,
0,
(HCRYPTPROV)NULL,
CERT_SYSTEM_STORE_LOCAL_MACHINE | CERT_STORE_READONLY_FLAG,
L"MY")
CertFindCertificateInStore(
hStore,
X509_ASN_ENCODING|PKCS_7_ASAN_ENCODING,
CERT_FIND_SUBJEECT_STR,
subject,
NULL);
RpcCertGeneratePrincipalNameW(
ccert_ctx_server,
RPC_C_FULL_CERT_CHAIN,
serverPrincName);
schannel.dwVersion = SCHANNEL_CRED_VERSION;
schannel.cCreds = 1;
schannel.paCred = &ccert_ctx_client;
RpcServerRegisterAuthInfoW(
serverPrincName,
RPC_C_AUTHN_GSS_SCHANNEL,
NULL,
&schannel);
RpcBindingSetAuthInfo(
hBind,
serverPrincName,
RPC_C_AUTHN_LEVEL_PKT_INTEGRITY,
RPC_C_AUTHN_GSS_SCHANNEL,
&schannelCred,
RPC_C_AUTHZ_NONE)
Given all of this RPC will work, but it will not be encrypted as verified with wireshark. I have worked this with a very minimal SCHANNEL structure definition and not using qos structure. Nothing makes much difference. the only thing that really makes a difference is if I change RPC_IF_ALLOW_CALLBACKS_WITH_NO_AUTH to RPC_IF_ALLOW_SECURE_ONLY. Then I get an access denied when making an RPC call. From what I understand this is the normal functionality of SCHANNEL and you must provide your own authentication within the Security Callback.
When I call RpcBindingInqAuthClient in my security callback I recieve the error 1746: The binding does not contain any authenticatioin information.
I have looked through MSDN, a the few various links scattered on the web, but there is little to know help on getting SCHANNEL working.
My choice for SCHANNEL is I can't rely on kerberos or ntlm. I am running tcp over the internet so certificates are what work for me. I can't use http because I can't setup IIS on my server, DCE seems to be even less documented than schannel.
Thanks!

Apache Camel MQXAQueueConnectionFactory

So well, I am trying to get a MQXAQueueConnectionFactory to work, I have created a extended class from the JmsComponent to handle username and password when sending data to the queue.
It does get/put messages on the queue, but in my case I've created a router to test the XA such as
from("wmq:queue:incomingQueue")
.process(new Processor(){
... Thread.sleep(20000)
})
.to("wmq:queue:outgoingQueue")
while being in sleep, I shut down the queuemanager. However when trying to get uncommited messages from the queue
DISPLAY QSTATUS('qChainQueue') i get CURDEPTH(0), while it should be 1 as I understand the XA part.
Am I doing this totally wrong?
How can it be tested?
HelpClass to handle WMQ:
public class WMQComponent extends JmsComponent {
private final String username;
private final String password;
public WMQComponent(String hostname, int port, String username, String password,
String queueManager, String channel) throws JMSException {
super();
this.username = username;
this.password = password;
MQXAQueueConnectionFactory connectionFactory = new MQXAQueueConnectionFactory();
connectionFactory.setTransportType(JMSC.MQJMS_TP_CLIENT_MQ_TCPIP);
connectionFactory.setFailIfQuiesce(1);
connectionFactory.setHostName(hostname);
connectionFactory.setPort(port);
connectionFactory.setQueueManager(queueManager);
connectionFactory.setChannel(channel);
setConnectionFactory(connectionFactory);
}
#Override
public Endpoint createEndpoint(String uri) throws Exception {
if (uri.contains("username") || uri.contains("password")) {
throw new IllegalStateException("Username and password is set by the component");
}
if (uri.contains("?")) {
return super.createEndpoint(uri + "&username=" + username + "&password=" + password);
} else {
return super.createEndpoint(uri + "?username=" + username + "&password=" + password);
}
}
}
With the following errors:
2015-03-25 14:01:12,077 [ #2 - Multicast] INFO dest_chain_ldap - org.springframework.jms.IllegalStateException: JMSWMQ0018: Failed to connect to queue manager 'QMBATCHESB' with connection mode 'Client' and host name 'hostname.com'.; nested exception is com.ibm.msg.client.jms.DetailedIllegalStateException: JMSWMQ0018: Failed to connect to queue manager 'QMBATCHESB' with connection mode 'Client' and host name 'hostname.com'. Check the queue manager is started and if running in client mode, check there is a listener running. Please see the linked exception for more information.; nested exception is com.ibm.mq.MQException: JMSCMQ0001: WebSphere MQ call failed with compcode '2' ('MQCC_FAILED') reason '2059' ('MQRC_Q_MGR_NOT_AVAILABLE').
at org.springframework.jms.support.JmsUtils.convertJmsAccessException(JmsUtils.java:279)
at org.springframework.jms.support.JmsAccessor.convertJmsAccessException(JmsAccessor.java:168)
at org.springframework.jms.core.JmsTemplate.execute(JmsTemplate.java:469)
at org.apache.camel.component.jms.JmsConfiguration$CamelJmsTemplate.send(JmsConfiguration.java:228)
at org.apache.camel.component.jms.JmsProducer.doSend(JmsProducer.java:431)
at org.apache.camel.component.jms.JmsProducer.processInOnly(JmsProducer.java:385)
at org.apache.camel.component.jms.JmsProducer.process(JmsProducer.java:153)
at org.apache.camel.processor.SendProcessor.process(SendProcessor.java:120)
at org.apache.camel.management.InstrumentationProcessor.process(InstrumentationProcessor.java:72)
at org.apache.camel.processor.interceptor.TraceInterceptor.process(TraceInterceptor.java:163)
at org.apache.camel.processor.RedeliveryErrorHandler.process(RedeliveryErrorHandler.java:416)
at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:191)
at org.apache.camel.processor.Pipeline.process(Pipeline.java:118)
at org.apache.camel.processor.Pipeline.process(Pipeline.java:80)
at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:191)
at org.apache.camel.component.direct.DirectProducer.process(DirectProducer.java:51)
at org.apache.camel.processor.SendProcessor.process(SendProcessor.java:120)
at org.apache.camel.management.InstrumentationProcessor.process(InstrumentationProcessor.java:72)
at org.apache.camel.processor.interceptor.TraceInterceptor.process(TraceInterceptor.java:163)
at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:191)
at org.apache.camel.processor.RedeliveryErrorHandler.process(RedeliveryErrorHandler.java:416)
at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:191)
at org.apache.camel.util.AsyncProcessorHelper.process(AsyncProcessorHelper.java:105)
at org.apache.camel.processor.MulticastProcessor.doProcessParallel(MulticastProcessor.java:732)
at org.apache.camel.processor.MulticastProcessor.access$200(MulticastProcessor.java:82)
at org.apache.camel.processor.MulticastProcessor$1.call(MulticastProcessor.java:303)
at org.apache.camel.processor.MulticastProcessor$1.call(MulticastProcessor.java:288)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
Caused by: com.ibm.msg.client.jms.DetailedIllegalStateException: JMSWMQ0018: Failed to connect to queue manager 'QMBATCHESB' with connection mode 'Client' and host name 'hostname.com'. Check the queue manager is started and if running in client mode, check there is a listener running. Please see the linked exception for more information.
at com.ibm.msg.client.wmq.common.internal.Reason.reasonToException(Reason.java:496)
at com.ibm.msg.client.wmq.common.internal.Reason.createException(Reason.java:236)
at com.ibm.msg.client.wmq.internal.WMQConnection.<init>(WMQConnection.java:430)
at com.ibm.msg.client.wmq.internal.WMQXAConnection.<init>(WMQXAConnection.java:70)
at com.ibm.msg.client.wmq.factories.WMQXAConnectionFactory.createV7ProviderConnection(WMQXAConnectionFactory.java:190)
at com.ibm.msg.client.wmq.factories.WMQConnectionFactory.createProviderConnection(WMQConnectionFactory.java:6210)
at com.ibm.msg.client.jms.admin.JmsConnectionFactoryImpl.createConnection(JmsConnectionFactoryImpl.java:278)
at com.ibm.mq.jms.MQConnectionFactory.createCommonConnection(MQConnectionFactory.java:6155)
at com.ibm.mq.jms.MQQueueConnectionFactory.createQueueConnection(MQQueueConnectionFactory.java:144)
at com.ibm.mq.jms.MQQueueConnectionFactory.createConnection(MQQueueConnectionFactory.java:223)
at org.springframework.jms.connection.UserCredentialsConnectionFactoryAdapter.doCreateConnection(UserCredentialsConnectionFactoryAdapter.java:175)
at org.springframework.jms.connection.UserCredentialsConnectionFactoryAdapter.createConnection(UserCredentialsConnectionFactoryAdapter.java:150)
at org.springframework.jms.support.JmsAccessor.createConnection(JmsAccessor.java:184)
at org.springframework.jms.core.JmsTemplate.execute(JmsTemplate.java:456)
... 29 more
Caused by: com.ibm.mq.MQException: JMSCMQ0001: WebSphere MQ call failed with compcode '2' ('MQCC_FAILED') reason '2059' ('MQRC_Q_MGR_NOT_AVAILABLE').
at com.ibm.msg.client.wmq.common.internal.Reason.createException(Reason.java:223)
... 41 more
Caused by: com.ibm.mq.jmqi.JmqiException: CC=2;RC=2059;AMQ9204: Connection to host 'hostname.com(1514)' rejected. [1=com.ibm.mq.jmqi.JmqiException[CC=2;RC=2059;AMQ9213: A communications error for occurred. [1=java.net.ConnectException[Connection refused: connect],3=hostname.com]],3=hostname.com(1514),5=RemoteTCPConnection.connnectUsingLocalAddress]
at com.ibm.mq.jmqi.remote.internal.RemoteFAP.jmqiConnect(RemoteFAP.java:1831)
at com.ibm.msg.client.wmq.internal.WMQConnection.<init>(WMQConnection.java:345)
... 40 more
Caused by: com.ibm.mq.jmqi.JmqiException: CC=2;RC=2059;AMQ9213: A communications error for occurred. [1=java.net.ConnectException[Connection refused: connect],3=hostname.com]
at com.ibm.mq.jmqi.remote.internal.RemoteTCPConnection.connnectUsingLocalAddress(RemoteTCPConnection.java:612)
at com.ibm.mq.jmqi.remote.internal.RemoteTCPConnection.protocolConnect(RemoteTCPConnection.java:940)
at com.ibm.mq.jmqi.remote.internal.system.RemoteConnection.connect(RemoteConnection.java:1097)
at com.ibm.mq.jmqi.remote.internal.system.RemoteConnectionPool.getConnection(RemoteConnectionPool.java:348)
at com.ibm.mq.jmqi.remote.internal.RemoteFAP.jmqiConnect(RemoteFAP.java:1503)
... 41 more
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:69)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:157)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:391)
at java.net.Socket.connect(Socket.java:579)
at java.net.Socket.connect(Socket.java:528)
at com.ibm.mq.jmqi.remote.internal.RemoteTCPConnection$2.run(RemoteTCPConnection.java:597)
at java.security.AccessController.doPrivileged(Native Method)
at com.ibm.mq.jmqi.remote.internal.RemoteTCPConnection.connnectUsingLocalAddress(RemoteTCPConnection.java:588)
... 45 more
The reason code 2059 and various errors stating that the connection was refused suggest either a mechanical issue (i.e. Listener not running) or an auths issue.
If I were attempting to debug this, the first thing I'd do is to enable authorization events, channel events, and any others you would normally enable. If you use MQ Explorer, also install the MS0P Plugin which will allow you to view the event messages in human-readable text.
Next, I would use the MQ sample programs to test. Since I always install the full client rather than grabbing the jar files, I have amqsputc available. However, the Java classes have IVT (initial verification test) programs. These ensure that the listener is running, the channel is configured and available, etc. As of v7.1 this also ensures that the CHLAUTH rules are set to allow the access. As of v8.0, or if you had the Capitalware exit installed, this also lets us test the user ID and password authentication.
The queue manager's error log and the event messages should provide good diagnostics, assuming the connection request makes it to MQ. Be sure to look both in the QMgr-specific error logs and the installation-global error logs.
Once I had confirmed that basic connectivity is in place, I'd reconcile my client-side configuration parameters for host, port, channel and if it is specified [shudder!] the QMgr name. Assuming these are correct and having proven basic connectivity works, it is now possible to test the app with some confidence.
The same method applies. First make sure the app's connection request makes it to the QMgr. If it does and is refused, the event messages and error logs will note this and why. If there is no indication of a failure in these places, the app isn't getting to the QMgr. The 2059 can indicate that the socket was refused, that the listener is up but the QMgr is not, that the channel instances have maxed out, or that after provisionally starting the channel it was closed by the QMgr, often due to a CHLAUTH rule. In any case, the event messages and error logs will have a detailed explanation as to why.
So I had done this a bit wrong, it was not enough to use the MQXAConnectionFactory but I had to create the JmsComponent as transacted.
Have tried to stop the queue manager while running the application and stop the application while handling a message and it seems to do the rollback as expected.
Ended up with
public static JmsComponent mqXAComponentTransacted(String hostname, int port, String username, String password,
String queueManager, String channel) throws JMSException {
MQXAQueueConnectionFactory connectionFactory = new MQXAQueueConnectionFactory();
connectionFactory.setTransportType(JMSC.MQJMS_TP_CLIENT_MQ_TCPIP);
connectionFactory.setFailIfQuiesce(1);
connectionFactory.setHostName(hostname);
connectionFactory.setPort(port);
connectionFactory.setQueueManager(queueManager);
connectionFactory.setChannel(channel);
UserCredentialsConnectionFactoryAdapter connectionFactoryAdapter=new UserCredentialsConnectionFactoryAdapter();
connectionFactoryAdapter.setTargetConnectionFactory(connectionFactory);
connectionFactoryAdapter.setUsername(username);
connectionFactoryAdapter.setPassword(password);
return JmsComponent.jmsComponentTransacted(connectionFactoryAdapter);
}
Also using the UserCredentialsConnectionFactoryAdapter, I didn't want to use Spring components but since the Jms package is already dependent of it, it was easier to use it than my previous solution to handle credentials.

Occasional, unpredictable exceptions with multi-threaded solrj queries

I have a multi-threaded application using solrj 4. There are a maximum of 25 threads. Each thread creates a connection using HttpSolrServer, and runs one query. Most of the time this works just fine. But occasionally I get the following exception:
Jan 10, 2013 9:29:07 AM org.apache.http.impl.client.DefaultRequestDirector tryConnect
INFO: I/O exception (java.net.NoRouteToHostException) caught when connecting to the target host: Cannot assign requested address
Jan 10, 2013 9:29:07 AM org.apache.http.impl.client.DefaultRequestDirector tryConnect
INFO: Retrying connect
Exception in thread "main" java.util.concurrent.ExecutionException: java.lang.NullPointerException
at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:252)
at java.util.concurrent.FutureTask.get(FutureTask.java:111)
I wrote some code to retry the query, if it fails:
while(!querySuccess && queryAttempts<m_MaxQueryAttempts ){
try{
queryAttempts++;
rsp = m_Server.query( query );
querySuccess = true;
}catch(SolrServerException e){
querySuccess = false;
}
}
After one or more retries the query usually works. But sometimes it fails even after 100 retries. Either way, I'd like to understand what the cause of the problem is. Why does it work some of the time? Is it an issue with concurrent access to solr? Apart from this process, I only have one other process that it continually writing to the index using a single connection. The default server settings are below - so I don't think it's because of too many simultaneous connections.
INFO: Creating new http client, config:maxConnections=128&maxConnectionsPerHost=32&followRedirects=false
Any suggestions on how to diagnose this would be much appreciated.

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