Why does AbortOnConnectFail option in ConfigurationOption for ConnectionMultiplexer from StackExchange.Redis still makes the connection multiplexer to throw Sentinel exception connection errors like:
Unhandled exception. StackExchange.Redis.RedisConnectionException: Sentinel: Failed connecting to configured master for service: mymaster
Is there a good way to configure it so that in case it fails, it will not throw the exception an just retry?
Here is an example of how I connect to Redis:
var redisConnectionConfiguration = new ConfigurationOptions
{
ClientName = "Foo",
EndPoints =
{
{ redisConfigSection["Host"] },
},
Password = redisConfigSection["Password"],
AllowAdmin = true,
AbortOnConnectFail = false,
ReconnectRetryPolicy = new ExponentialRetry(2000),
ServiceName = isRedisSentinelEnabled ? "mymaster" : null,
};
var redisConnection = ConnectionMultiplexer.Connect(redisConnectionConfiguration, Console.Out);
We can use ConnectionMultiplexer deal with disconnection, you can check my smaple code.
Reconnecting with Lazy pattern
We have seen a few rare cases where StackExchange.Redis fails to reconnect after a connection blip (for example, due to patching). Restarting the client or creating a new ConnectionMultiplexer will fix the issue. Here is some sample code that still uses the recommended Lazypattern while allowing apps to force a reconnection periodically. Make sure to update code calling into the ConnectionMultiplexer so that they handle any ObjectDisposedException errors that occur as a result of disposing the old one.
Related
I’m having issues running realm with xUnite and Net core. Here is a very simple test that I want to run
public class UnitTest1
{
[Scenario]
public void Test1()
{
var realm = Realm.GetInstance(new InMemoryConfiguration("Test123"));
realm.Write(() =>
{
realm.Add(new Product());
});
var test = realm.All<Product>().First();
realm.Write(() => realm.RemoveAll());
}
}
I get different exceptions on different machines (Windows & Mac) on line where I try to create a Realm instace with InMemoryConfiguration.
On Mac I get the following exception
libc++abi.dylib: terminating with uncaught exception of type realm::IncorrectThreadException: Realm accessed from incorrect thread.
On Windows I get the following exception when running
ERROR Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. at
System.Net.Sockets.NetworkStream.Read(Span1 destination) at
System.Net.Sockets.NetworkStream.ReadByte() at
System.IO.BinaryReader.ReadByte() at
System.IO.BinaryReader.Read7BitEncodedInt() at
System.IO.BinaryReader.ReadString() at
Microsoft.VisualStudio.TestPlatform.CommunicationUtilities.LengthPrefixCommunicationChannel.NotifyDataAvailable() at
Microsoft.VisualStudio.TestPlatform.CommunicationUtilities.TcpClientExtensions.MessageLoopAsync(TcpClient client, ICommunicationChannel channel, Action1 errorHandler, CancellationToken cancellationToken) Source: System.Net.Sockets HResult: -2146232800 Inner Exception: An existing connection was forcibly closed by the remote host HResult: -2147467259
I’m using Realm 3.3.0 and xUnit 2.4.1
I’ve tried downgrading to Realm 2.2.0, and it didn’t work either.
The solution to this problem was found in this Github post
The piece of code from that helped me to solve the issue
Realm GetInstanceWithoutCapturingContext(RealmConfiguration config)
{
var context = SynchronizationContext.Current;
SynchronizationContext.SetSynchronizationContext(null);
Realm realm = null;
try
{
realm = Realm.GetInstance(config);
}
finally
{
SynchronizationContext.SetSynchronizationContext(context);
}
return realm;
}
Though it took a while for me to apply this to my solution.
First and foremost, instead of just setting the context to null I am using Nito.AsyncEx.AsyncContext. Because otherwise automatic changes will not be propagated through threads, as realm needs a non-null SynchronizationContext for that feature to work. So, in my case the method looks something like this
public class MockRealmFactory : IRealmFactory
{
private readonly SynchronizationContext _synchronizationContext;
private readonly string _defaultDatabaseId;
public MockRealmFactory()
{
_synchronizationContext = new AsyncContext().SynchronizationContext;
_defaultDatabaseId = Guid.NewGuid().ToString();
}
public Realm GetRealmWithPath(string realmDbPath)
{
var context = SynchronizationContext.Current;
SynchronizationContext.SetSynchronizationContext(_synchronizationContext);
Realm realm;
try
{
realm = Realm.GetInstance(new InMemoryConfiguration(realmDbPath));
}
finally
{
SynchronizationContext.SetSynchronizationContext(context);
}
return realm;
}
}
Further, this fixed a lot of failing unit tests. But I was still receiving that same exception - Realm accessed from incorrect thread. And I had no clue why, cause everything was set correctly. Then I found that the tests that were failing were related to methods where I was using async realm api, in particular realm.WriteAsync. After some more digging I found the following lines in the realm documentation.
It is not a problem if you have set SynchronisationContext.Current but
it will cause WriteAsync to dispatch again on the thread pool, which
may create another worker thread. So, if you are using Current in your
threads, consider calling just Write instead of WriteAsync.
In my code there was no direct need of using the async API. I removed and replaced with sync Write and all the tests became green again! I guess if I find myself in a situation that I do need to use the async API because of some kind of bulk insertions, I'd either mock that specific API, or replace with my own background thread using Task.Run instead of using Realm's version.
We had implemented Redis session state provider to our web application and it works like a charm but i wonder what happens if redis server fails or web server couldn't connect to redis server.
Is there any way to use InProc Session State management as failover of Redis?
I cannot find any documentation about declaring multiple session state providers so if redis fails, system can continue to work with using inproc. (I accept to lose session states in redis and start from scratch in case of fail and lose again session states inproc and start from scratch again if redis become available)
You need to define slave for your redis-server and use redis sentinel to monitor your server
I have been having a similar issue with Redis failing as a backing for our session store and I can not find anything that allows for failover/failback to an other SessionStateProvider.
I was hoping there was something out there that would write to both Redis and SqlServer in mem table or similar and then read from 1, if fails read from 2. But, this does not seem to exist yet.
I'm using StackExchange library to connect to redis server.It's just a simple code which just shows how to subscribe to event and don't take it a final solution.Whenever sentinel chooses new server you will receive an event for that so you can select new server.
ConnectionMultiplexer multiplexer =
ConnectionMultiplexer.Connect(new ConfigurationOptions
{
CommandMap = CommandMap.Sentinel,
EndPoints = { { "127.0.0.1", 26379 }, { "127.0.0.1", 26380 } },
AllowAdmin = true,
TieBreaker = "",
ServiceName = "mymaster",
SyncTimeout = 5000
});
multiplexer.GetSubscriber().Subscribe("*", (c, m) =>
{
Debug.WriteLine("the message=" + m);
Debug.WriteLine("channel=" + c);
try
{
var sentinelServer = multiplexer.GetServer("127.0.0.1", 26379).SentinelGetMasterAddressByName("mymaster");
Debug.WriteLine("Current server=" + sentinelServer);
Debug.Flush();
}
catch (Exception)
{
var sentinelServer = multiplexer.GetServer("127.0.0.1", 26380).SentinelGetMasterAddressByName("mymaster");
Debug.WriteLine("Current server=" + sentinelServer );
Debug.Flush();
}
});
I use SignalR 2.0.0 Win2012 iis8 with two environment with two different ips.
one environment service is up and second is down(purposely)
use websocket protocol.
i have the following scenario:
When i connect to first environment and want to connect to the second.
i disconnected from first environment and try connect to second environment i get error(its correct behavior)
i try to reconnect back to the first environment but I get still the same error.
the error is "Error during negotiation request."
after refresh the browser i can connect success again to first environment.
What am i doing wrong?
this is part of my code:
function connect(host)
{
var hubConnection = $.hubConnection.('');
hubConnection.url = host;
hubConnection.start()
.done(open)
.fail(error);
}
function open()
{
console.log('login success')
}
function disconnect()
{
var self = this,
hubConnection = $.hubConnection("");
console.log('disconnect ')
hubConnection.stop(true, true);
}
function error(error)
{
var self = this,
hubConnection = $.hubConnection("");
console.log('connection error ')
if(error && hubConnection.state !== $.connection.connectionState.connected)
{
.....
.....
//logic detemninate wich environment ip was previous
connect(environment ip)
}
}
//occured when button disconnect clicked
function disconnectFromFirstEnvironmentAndConnectToSecond()
{
disconect();
connect(second environment ip);
}
.....
.....
connect(first environment ip);
You're not retaining your first connection reference.
Aka you create a HubConnection and then never capture it in a scope that can be used later; therefore when you disconnect later the connection.stop does nothing because it's not calling stop on the HubConnection that was originally started.
This could ultimately lead to you having too many concurrently open requests which will then not allow you to negotiate with a server hence your error.
I'd recommend fixing how you stop/start connections. Next if the issue still occurs I'd inspect the network traffic to ensure that valid requests are being made.
I am using the HTTP Connection in the following way:
HttpConnection _httpConnection = null;
try {
_httpConnection = (HttpConnection)Connector.open(_url);
} catch(Exception e) { }
byte [] postDataBytes = _postData.getBytes();
_httpConnection.setRequestMethod(HttpConnection.POST);
_httpConnection.setRequestProperty("User-Agent","Profile/MIDP-2.0 Configuration/CLDC-1.0");
_httpConnection.setRequestProperty("Content-Language", "en-US");
_httpConnection.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
_httpConnection.setRequestProperty("Connection", "close");
_httpConnection.setRequestProperty("Content-Length", Integer.toString(_postData.getBytes().length));
os = _httpConnection.openOutputStream();
os.write(postDataBytes);
os.flush();
This HTTP Connection requires parameters to successfully open. For example on a WIFI network, it requires the ";deviceside=true;interface=wifi" to be added to the URL.
The problem is for the EDGE connection. Each country requires different parameters to be added. For example in lebanon it requires ";deviceside=false" but in KSA if i add this parameter the connection will not open. In USA it needs different types of parametes. The question is how to establish an HTTP connection for all the countries with the same parameters. So that the application will successfully have an internet connection no matter where it is downloaded.
Welcome to the confusing world of network transports on BlackBerry! You will want to start with the article Connecting your BlackBerry - http and socket connections to the world.
Here is a simple example for "just give me a connection" (note, you will need to add appropriate error handling; also, myURL in the code below should have no connection descriptor info appended to it):
ConnectionFactory factory = new ConnectionFactory();
ConnectionDescriptor descriptor = factory.getConnection(myURL);
if (descriptor != null) {
_httpConnection = (HttpConnection) descriptor.getConnection();
...
}
Try using to use the method reffered in this link melick-rajee.blogspot.com and use it like
_url = "http://www.example.com";
_httpConnection = (HttpConnection)Connector.open(_url + getConnectionString());
You will have to sign the application to use this else the application will show exception.
To sign your application just go here Code Signing Keys
To use the connectionFactory, seems you need to set BisBOptions.
Try this:
connFact = new ConnectionFactory();
connFact.setTransportTypeOptions(TransportInfo.TRANSPORT_BIS_B,
new BisBOptions("mds-public"));
So we have console-hosted WCF Service and ASP.NET WEB Service (on IIS).
After some tough operation WCF Service must return some (large) data to ASP.NET Web Service for next processing. I tested on small results and everything is ok.
But after testing on real data that is a serialized result object that is near 4.5 MB, an error occurs on ASP.NET Web Service, which is the client in wcf-client-server communication.
This is the error I got:
The socket connection was aborted. This could be caused by an error
processing your message or a receive timeout being exceeded by the
remote host, or an underlying network resource issue. Local socket
timeout was '04:00:00'. Inner Exception: SocketException:"An existing
connection was forcibly closed by the remote host" ErrorCode = 10054
Messages size are configured by next binding (on server and client):
NetTcpBinding netTcpBinding = new NetTcpBinding();
netTcpBinding.TransactionFlow = true;
netTcpBinding.SendTimeout = new TimeSpan(0, 4,0, 0);
netTcpBinding.Security.Mode = SecurityMode.None;
netTcpBinding.Security.Message.ClientCredentialType = MessageCredentialType.None;
netTcpBinding.Security.Transport.ClientCredentialType = TcpClientCredentialType.None;
netTcpBinding.Security.Transport.ProtectionLevel = ProtectionLevel.None;
netTcpBinding.MaxReceivedMessageSize = 2147483647;
netTcpBinding.MaxBufferSize = 2147483647;
netTcpBinding.MaxBufferPoolSize = 0;
netTcpBinding.ReaderQuotas.MaxStringContentLength = int.MaxValue;
netTcpBinding.ReaderQuotas.MaxArrayLength = int.MaxValue;
netTcpBinding.ReaderQuotas.MaxBytesPerRead = int.MaxValue;
netTcpBinding.ReaderQuotas.MaxDepth = 32;
netTcpBinding.ReaderQuotas.MaxNameTableCharCount = 16384;
MaxObjectsInGraph property is configured in a config file.
What can you advise me? And also I need example how programmatically set MaxObjectsInGraph property on client and server.
Thanks for answers.
Problem is fixed by setting programmatically MaxObjectsInGraph(for serializer) as a service attribute.