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.
Related
I use aws-neptune.
And I try to implement my queries as transactional(with sessionClient like: https://docs.aws.amazon.com/neptune/latest/userguide/access-graph-gremlin-sessions.html). But when I try to implement it, closing client throws exception. There is similar issue like my case: https://groups.google.com/g/janusgraph-users/c/N1TPbUU7Szw
My code looks like:
#Bean
public Cluster gremlinCluster()
{
return Cluster.build()
.addContactPoint(GREMLIN_ENDPOINT)
.port(GREMLIN_PORT)
.enableSsl(GREMLIN_SSL_ENABLED)
.keyCertChainFile("classpath:SFSRootCAG2.pem")
.create();
}
private void runInTransaction()
{
String sessionId = UUID.randomUUID().toString();
Client.SessionedClient client = cluster.connect(sessionId);
try
{
client.submit("query...");
}
finally
{
if (client != null)
{
client.close();
}
}
}
And exception is:
INFO (ConnectionPool.java:225) - Signalled closing of connection pool on Host{address=...} with core size of 1
WARN (Connection.java:322) - Timeout while trying to close connection on ... - force closing - server will close session on shutdown or expiration.
java.util.concurrent.TimeoutException
at java.util.concurrent.CompletableFuture.timedGet(CompletableFuture.java:1771)
Is there any suggestion?
This might be a connectivity problem with the server which you are not able to observe while sending the query because you are not waiting for the future to complete.
When you do a client.submit("query...");, you receive a future. You need to wait for that future to complete to observe any exceptions (or success).
I would suggest the following:
Try hitting the server with a health status call using curl to verify connectivity with the server.
Replace the client.submit("query..."); with client.submit("query...").all().join(); to get the error during connection with the server.
I'm implementing a Thrift client in order to make connection to a built-in scribe server.
Everything is going OK if I use a standard Log method, like this:
public boolean log(List<LogEntry> messages) {
boolean ret = false;
PooledClient client = borrowClient();
try {
if ((client != null) && (client.getClient() != null)) {
ResultCode result = client.getClient().Log(messages);
ret = (result != null && result.equals(ResultCode.OK));
returnClient(client);
}
} catch (Exception ex) {
logger.error(LogUtil.stackTrace(ex));
invalidClient(client);
}
return ret;
}
However, when I use send_Log instead:
public void send_Log(List<LogEntry> messages) {
PooledClient client = borrowClient();
try {
if ((client != null) && (client.getClient() != null)) {
client.getClient().send_Log(messages);
returnClient(client);
}
} catch (Exception ex) {
logger.error(LogUtil.stackTrace(ex));
invalidClient(client);
}
}
It acctually causes some problems:
Total network connection to port 1463 (default port for a scribe server) is going to increase so much, and always in a CLOSE_WAIT state.
Cause my application got stuck without throwing any error, I think it may be an issue with network connection.
what if send without recv
As this is clearly TCP, the sender will block (in blocking mode), or incur EAGAIN/EWOULDBLOCK in non-blocking mode. EDIT It is now clear that you want to send without receiving the reply. You can do that by just sending and then closing the socket, but that may cause the peer to incur ECONNRESET, which may upset it. You should really implement the application protocol correctly.
1/ Total network connection to port 1463 (default port for a scribe server) is going to increase so much, and always in a CLOSE_WAIT state.
Lots of ports in CLOSE_WAIT state indicates a socket leak on the part of the local application.
2/ Cause my application got stuck without throwing any error. I think it may be an issues with network connection.
It is an issue with sending and not receiving.
Since you labelled this as a Thrift related question, the answer is oneway.
service foo {
oneway void FireAndForget(1: some args)
}
The oneway keyword does exactly what the name suggests. You get a client implementation that only sends and does not wait for anything to be returned from the server. This rule also includes exceptions. Hence a oneway method must always be void and can't throw any exceptions.
However, when I use send_Log instead ...
client.getClient().send_Log(messages);
Neither one of the Thrift-generated send_Xxx and recv_Xxx methods are meant to be public. That's why they are usually either private or protected methods. They should not be called directly, unless you are sure that you know what you are doing (and very obviously the latter is not the case here).
And since the real question is about performance: Why don't you just delegate the call(s) into a secondary thread? That way the I/O will not block the UI.
I recently created a proof of concept console application using SignalR (self host). It worked a treat for our use. The client connected fine and I was able to send updates from the server to the client. Lovely!
I've now transferred the code from the Console application to a winforms application for a prettier UI. Now that same client won't connect to the server yet it will still connect to the old Console version.
Winforms code:
string url = "http://localhost:8080";
using (WebApp.Start(url))
{
// Let the app know the server is up
}
Console code:
string url = "http://localhost:8080";
using (WebApp.Start(url))
{
Console.WriteLine("Server running on {0}", url);
Console.ReadLine();
}
Client connection code:
if (!connected)
{
int i = 0;
// Try 3 times
while (i <= 2)
{
try
{
string server = Properties.Settings.Default.Server + ":" + Properties.Settings.Default.PortNumber.ToString();
connection = new HubConnection(server);
connection.StateChanged += connection_StateChanged;
hub = connection.CreateHubProxy("MyHub");
connection.Start().Wait();
hub.On<string>("addMessage", param => { UpdateAlarmStatus(param); });
return true;
}
catch (Exception)
{
i++;
}
}
return false;
}
else
{
return true;
}
The error the client is reporting is:
Exception:Thrown: "No connection could be made because the target machine actively refused it" (System.Net.Sockets.SocketException)
A System.Net.Sockets.SocketException was thrown: "No connection could be made because the target machine actively refused it"
Time: 25/01/2015 15:09:23
Thread:Worker Thread[8232]
Why would the target machine (localhost) refuse itself which the Console version doesn't? I've been looking at the code over and over and I cannot see where I'm going wrong. Can anyone point me in the right direction please?
Thank you for reading.
Paul.
I suspect this is an issue with the configuration of your machine/infrastructure rather than the code itself, which looks fine at first glance.
Have you checked the console debug output in Visual Studio? I recently encountered an issue with similar symptoms and that was what gave me the initial clue to keep investigating. In my particular case, an exception was written to the console debug output that didn't make it to the client.
SignalR will normally negotiate with the server automatically to determine the best transport method to use. In a .NET client, the available options are LongPollingTransport, ServerSentEventsTransport and WebSocketTransport. So for some reason, your console app can use at least one of those methods, whereas your WinForms client cannot.
You can perhaps enable tracing to give you more information to work with. To do this, enter the below before you create the hub proxy:
hubConnection.TraceLevel = TraceLevels.All;
hubConnection.TraceWriter = Console.Out;
ASP.NET doco on SignalR tracing
I implemented a graceful stop to our node.js server. Basically something like this:
var shutDown = function () {
server.on('close', function () {
console.log('Server ' + process.pid + ' closed.');
process.exit();
});
console.log('Shutting down ' + process.pid + '...');
server.close();
}
However, when I close the server like this, I get a Error: socket hang up error in my continuous requests.
I thought that server.close() would make the server stop listening and accepting new requests, but keep processing all pending/open requests. However, that should result in an Error: connect ECONNREFUSED.
What am I doing wrong?
Additional info: The server consists of a master and three forked children/workers. However, the master is not listening or binding to a port, only the children are, and they are shut down as stated above.
Looking at the docs, it sounds like server.close() only stops new connections from coming in, so I'm pretty sure the error is with the already-open connections.
Maybe your shutDown() can check server.connections and wait until there are no more?
var shutDown = function(){
if(server.connections) return setTimeout(shutDown, 1000);
// Your shutDown code here
}
Slightly uglier (and much less scalable), but without the wait: you can keep track of connections as they occur and close them yourself
server.on('connection', function(e){
// Keep track of e.connection in a list.
// You'll want to remove e.connection
// from the list if it closes on its own
}
var shutDown = function(){
// Close all remaining connections in the list
// Your shutDown code here
}
I am using signalr 0.4 on an aspx-Page,
var hub = $.connection.FooHub;
hub.disconnected(function () {
log("Server has disconnected");
});
hub.ShowInfo = function (Info) { .... }
$("#Button1").click(function () {
hub.FooFunction('foo');
});
$.connection.hub.start();
The Hub is defined as :
public class FooHub : Hub, IDisconnect
{
~FooHub()
{
log.Debug("FooHub Destroy");
}
public FooHub()
{
log.Debug("FooHub Startup");
}
public bool FooFunction(string stuff)
{
log.Debug("Hub FooFunction");
Clients.ShowInfo(someInfo);
return true;
}
public Task Disconnect()
{
// Query the database to find the user by it's client id etc. etc.
MyController.Disconnect(Context.ConnectionId);
log.Debug("Hub Disconnnect " + Context.ConnectionId);
return null;
}
......
}
When i open the page and immediately click on Button1
it calls the Hub which in turn calls the ShowInfo-function on the page.
With Firebug i can see that signalr is using long-polling for the communcation.
So everything works as expected.
But when i then wait a couple of minutes
i see that
FooHub is destroyed
Disconnect is called in the Hub,
however on the Page there is no new connection
Firebug shows the old one still being executed
and when i then click on the Button -
FooFunction is called (i see a new connection in firebug)
FooHub is created
FooFunction is executed in the Hub (there is a line in the Log)
but ShowInfo is not executed
Is this a bug in SignalR or do i have to do something else to get the ShowInfo-call?
Update (Possible answer):
It was using a Forever-Frame and not long-polling.
In addition, the problem seems to happen mostly when using mobile internet (usb-stick) and Firefox.
Changing the transport to long-Polling seems to fix this issue.
You mention switching to long polling instead of using a forever frame but didn't say how to do that. You can specify which transports to try when starting the connection.
connection.start({ transport: ['longPolling','webSockets'] });
See https://github.com/SignalR/SignalR/wiki/SignalR-JS-Client for more options.
Did u look at this https://github.com/SignalR/SignalR/wiki/Configuring-SignalR
Try this see. To me as per your code every thing seems to be OK. Also can you test the same in Chrome and see whats happening.