I am using Consul for Service Discovery; and supply list of servers in NameResolver.start(Listener listener) during Client startup.
How can i add new Servers that Joined-in as Service Providers (in Consul)
I am using Round Robin; and when one of the server dies; it keeps hitting the dead server
Would you have a sample to retry on UNAVAILABLE exception? I just want to retry atleast once before giving up on the Client side.
Thank you in Advance
When the list of servers change (in Consul), call NameResolver.Listener.onUpdate(), which you should be calling at least once already.
The load balancing implementations and APIs are receiving a massive rework, which should greatly improve round robin.
I wrote my own LoadBalancer; and #Override pickTransport() to RoundRobin healthy gRPC servers from Consul.
In here I use consul as my registry. It works correctly.
It contain both example of Eureka and consul.
https://github.com/WThamira/gRpc-spring-boot-example
Related
I have a configuration with the following server/clients :
One server with two bound sockets, a REP and a ROUTER
A client (we will call it a worker) that stays connected to the ROUTER socket
Another (real) client that connects on the REP socket.
I want the server to be able to tell the real client to connect (directly or somehow through the server) to a websocket, opened on the worker client. But it seems, I cannot retrieve the worker's IP-address from a ZeroMQ socket.
How could I achieve this, without some dirty IP-address retrieve hacks?
How could I achieve this, without some dirty IP-address retrieve hacks?
The best would be to use an explicitly communicated IP-address dialogue / handshaking between the server and the worker which would take place upon their setup / initialisation, in which the worker adviced these configuration details to server, upon having been asked to provide a such answer.
Given that, the "new"-real-client .connect()-s it's REQ onto the server's REP, and asks the server about where to go next, the server thus can answer this and the "new"-real-client will get received this way a legitimate IP-address:port# and any additionally needed details for any additional TCP/IP-L3 service establishment and use.
That simple :o) distributed-system
Design-side Epilogue:Because there are some further, design-side implications, hardwired inside of each type of the ZeroMQ sockets' Access-Point, it might be found more appropriate to serve a separate REP-AccessPoint on the server side, so as not to subordinate each "new"-real-client to become dependent upon a presence of events outside of the domains of control of both the server and such "new"-real-client, but to rather allow both such REQ/REP-endpoints to enjoy the independence of anything but their temporally (semi-)private details (re-)negotiation(s).
I have an ASP.NET Web API application running behind a load balancer. Some clients keep an HTTP busy connection alive for too much time, creating unnecessary affinity and causing high load on some server instances. In order to fix that, I wish to gracefully close a connection that is doing too much requests in a short period of time (thus forcing the client to reconnect and pick a different server instance) while at same time keeping low traffic connections alive indefinitely. Hence I cannot use a static configuration.
Is there some API that I can call to flag a request to "answer this then close the connection" ? Or can I simply add the Connection: close HTTP header that ASP.NET will see and close the connection for me?
It looks like the good solution for your situation will be the built-in IIS functionality called Dynamic IP restriction. "To provide this protection, the module temporarily blocks IP addresses of HTTP clients that make an unusually high number of concurrent requests or that make a large number of requests over small period of time."
It is supported by Azure Web Apps:
https://azure.microsoft.com/en-us/blog/confirming-dynamic-ip-address-restrictions-in-windows-azure-web-sites/
If that is the helpful answer, please mark it as a helpful or mark it as the answer. Thanks!
I am not 100% sure this would work in your situation, but in the past I have had to block people coming from specific IP addresses geographically and people coming from common proxies. I created an Authorized Attribute class following:
http://www.asp.net/web-api/overview/security/authentication-filters
In would dump the person out based on their IP address by returning a HttpStatusCode.BadRequest. On every request you would have to check a list of bad ips in the database and go from there. Maybe you can handle the rest client side, because they are going to get a ton of errors.
Write an action filter that returns a 302 Found response for the 'blocked' IP address. I would hope, the client would close the current connection and try again on the new location (which could just be the same URL as the original request).
My job is to write a distributed client/server application with some concurrent tasks. So i decided to use akka.net for the concurrency issues. To implement the ipc between server and client akka remote is used. For some reasons there may run more than one client of the same type on a workstation. So i configured these clients for dynamic assignment of a tcp port. This worked fine for sending messages to the server.
My problem is to push some information to the clients. To accomplish this task an actor on the client exist. Now the server creates a reference for this actor. Therefor it needs the port the client is listening on . My idea is to send the tcp port the client uses to the server in some sort of connection procedure using a actor on the server.
After searching for some hours I didn't find any hint where to find the dynamically assigned tcp port. So how would the client get the assigned tcp port?
Ok, I could use akka.cluster. But using akka.cluster is breaking a fly on the wheel, I think. And if it solves my issue reamins to be seen.
Two suggestions, assuming that it is your client that makes the first contact with the server.
I'd have the server keep track of which clients are connected. I'd probably have a heartbeat message that gets sent once every few seconds from each client system. This way you can store an IActorRef for each alive client and send messages back without the need for finding the port. IActorRefs are preferable wherever possible for location transparency.
If you actually need to explicitly find the port, you may be able to extract it from the Path property of the IActorRef of one of the actors on the client system.
Thanks to patricks suggestions my issue is solved.
The solution is to extract the needed information from the senders path available while executing the hello message. With this information the server is able to maintain a list of all connected clients and theire network address.
Thanks a lot # patrick.
Regards Gregor
I am working with a client/server application which uses HTTP, and my goal is to add new features to it. I can extend the client by hooking my own code to some specific events, but unfortunately the server is not customizable. Both client and server are in a Windows environment.
My current problem is that performance is awful when a lot of data are received from the server: it takes time to transmit it and time to process it. The solution could be to have an application on server side to do the processing and send only the result (which is much smaller). The problem is there is not built-in functions to manipulate responses from the server before sending them.
I was thinking to listen to all traffic on port 80, identifying relevant HTTP responses and send them to my application while blocking the response (to avoid sending huge data volume which won't be processed by the client). As I am lacking a lot of network knowledge, I am a bit lost when thinking about how to do it.
I had a look at some low-level packet intercepting methods like WinPCap, but it seems to require a lot of work to do what I need. Moreover I think it is not possible to block or modify responses with this API.
A reverse proxy which allows user scripts to be triggered by specific requests or responses would be perfect, but I am wondering if there is no simpler way to do this interception/send elsewhere work.
What would be the simplest and cleanest method to enable this behavior?
Thanks!
I ended making a simple reverse proxy to access the HTTP server. The reverse proxy then extracts relevant information from the server response and sends it to the server-side processing component, and replaces information extracted from the response by an ID the client uses to request the other component to get the processing results.
The article at http://www.codeproject.com/KB/web-security/HTTPReverseProxy.aspx was very helpful to make the first draft of the reverse proxy.
Hmm.... too much choices.
2 ideas:
configure on all clients a Http Proxy. there are some out there, that let you manipulate what goes through in both directions (with scripts, plugins).
or
make a pass through project, that listens to port 80, and forewards the needed stuff to port 8080 (where your original server app runs)
question is, what software is the server app running at,
and what knowledge (dev) do you have?
ah. and what is "huge data"? kilobyte? megabyte? gigabyte?
I'm writing an ASP.NET web application which will run on Windows Server 2008 (IIS7).
Each page's codebehind will need to make at least one synchronous web service call to an external server using HttpWebRequest and GET.
My question - is there any limit to the number of outbound HttpWebRequest calls I can make? (assume that the server I'm calling has no limit)
Is there any means to pool these connections to make the app scale better? Would a web garden configuration help?
By default, an HTTP/1.1 server is limited to two connection, and a HTTP/1.0 server is limited to four connections. So, your ASP.NEt app will have serious throughput problems if you are trying to issue more than two outstanding requests to an HTTP/1.1 server, for eg.
You will need to increase the connection limit, either per server, or globally.
For eg, globally:
ServicePointManager.DefaultConnectionLimit = 10; // allow 10 outstanding connections
Hope this helps.
I think your question should be geared toward network configurations.
I'd say you are asking for trouble if every page is dependent on a synchronous external call. What if you get N number of request that get hung on the external web service(s)? You will have some issues on your end then and you can do nothing about it.
Have you considered async calls with callbacks?
EDIT: Asynchronous Pages in ASP.NET 2.0
The following link points to a really great article for optimizing Asp.net.
http://www.codeproject.com/KB/aspnet/10ASPNetPerformance.aspx
Hope it helps ;)