We want to limit the number of connections for our rest web service.
We are using spring boot with jetty as server.
We have configured below settings :
#rate limit connections
server.jetty.acceptors=1
server.jetty.selectors=1
#connection time out in milliseconds
server.connection-timeout=-1
Now, as you can see that there is no idle timeout applicable for connections.
Which means a connection once open will remain active until it is explicitly closed.
So, with this settings, my understanding is that if I open more then 1 connection, then I should not get any response because the connection limit is only 1.
But this does not seem to be working. Response is sent to each request.
I am sending request with 3 different clients. I have verified the ip address and ports. They all are different for 3 clients. But all 3 remains active once connection is established.
Any experts to guide on the same?
Setting the acceptors and selectors to 1 will not limit the max number of connections.
I suggest you look at using either the jetty QoS filter, or the Connection Limit jetty module.
Related
We want to use spring websockets + STOMP + amazon MQ as a full featured message broker. We were trying to do benchmarking, to find out how many client websocket connections single tomcat node can handle. But it appears that we hit amazonMQ connection limit first. As per the aws documentation, amazonMQ has a limit of 1000 connections per node (as far as I understand we can ask support to increase the limit, but I doubt that it can be increased big time). So my questions is:
1) Am I correct in assuming that for every websocket connection from client to spring/tomcat server, a corresponding connection being opened from server to broker? Is this correct behavior or we're doning something wrong here/missing something?
2) What can be done here? I mean I don't think this is a good idea to create broker node per evry 1000 users..
According to https://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/messaging/simp/stomp/StompBrokerRelayMessageHandler.html your are doing everything right, and it is documented behavior.
Quote from javadoc:
For each new CONNECT message, an independent TCP connection to the broker is opened and used exclusively for all messages from the client that originated the CONNECT message. Messages from the same client are identified through the session id message header. Reversely, when the STOMP broker sends messages back on the TCP connection, those messages are enriched with the session id of the client and sent back downstream through the MessageChannel provided to the constructor.
As for a fix, you can write your own message broker relay, with tcp connection pooling.
Just starting to use Spring Webflux Webclient,Just wanted to know what is the default KeepAlive time for the Http Connection ? Is there a way to increase the keepAlive Time? In our Rest Service we get a request probably every five minutes,The request takes long time to process .It takes time between 500 seconds-- 10 second. However in load test if I send frequent requests the processing time is less than 250ms.
Spring WebFlux WebClient is an HTTP client API that wraps actual HTTP libraries - so configuration like connection management, timeouts, etc. are configured at the library level directly and behavior might change depending on the chosen library.
The default library with WebClient is Reactor Netty.
Many HTTP clients (and this is the case with Reactor Netty) are maintaining HTTP connections in a connection pool to reuse them. Clients usually acquire a new connection to a remote host, use it to send/receive information and then put it back in the connection pool. This is very useful since sometimes acquiring a new connection can be costly. This seems to be really costly in your case.
HTTP clients leave those unused connections in the pool, but what about keepAlive time?
Most clients leave those connections in the pool as long as possible and test them before acquiring them to see if they're still valid or listen to server events asynchronously to remove them from the pool (I believe Reactor Netty does that). So ultimately, the server is in control and decides when to close connections if they're inactive.
Now your problem description might suggest that connecting to that remote host is very costly, but it could be also the remote host taking a long time to respond to your requests (for example, it might be operating on an empty cache and needs to calculate a lot of things).
I'm looking after a Spring rest application that uses GrizzlyHttpServer as HTTP server. I need to know what's the default maximum number of concurrent connections that this server can handle?
Anybody knows how can I test the numbers of connections that transport is currently creating on the pool of the connections, it is clear that in the code I have put MaxIdleConnsPerHost: 5 like number maximum of connections on the pool and DisableKeepAlives: false like the option which let to reuse the connection
but I do not sure about how Go is managed this topic and the documentation is not clear Source-code-transport.go , Documentation-net/http
Server is a example of a server that receive a XML and send the same XML like response with an attribute more.
Client is the code that has the configuration of the pool and send 100 request to server.
Hi Our EMS server is used by other clients for putting message. But some time they dont close connections and number of connections is reaching maximum limit of the server. Is there any way where we can restrict the number of connections for the client based on emsusername provided to the client or based on the host name from where client is creating connection. Is there any configuration we can do for client specific connections restriction.
No, there is no such provision in EMS server or client libraries where you can restrict the number of consumer/producer clients based on their user names or other properties. You can have a look at the JAAS and JACI provision supported by EMS which can be used to write your own JAVA authentication custom modules which run in JVM within EMS server. You can find more information about JAAS and JACI on Oracles documentation site.
Have you looked into the server_timeout_client_connection setting ?
From the doc :
server_timeout_client_connection = limit
In a server-to-client connection, if the server does not receive a heartbeat for a
period exceeding this limit (in seconds), it closes the connection.
We recommend setting this value to approximately 3 times the heartbeat interval, as it is specified in client_heartbeat_server.
Zero is a special value, which disables heartbeat detection in the server (although
clients still send heartbeats).