topic Re: Run multiple webserver instance in FlexSim Forum

Run multiple webserver instance

amerloQ2XZU — Tue, 14 May 2024 08:28:17 GMT

[ FlexSim 24.0.3 ]

Hi community,

I have an issue with the webserver and I am searching a solution.

I need to run two different webservers in the same machine to support two different FlexSim versions.

If I run one webserver per time, everythings works. When I run both simultaneously, only one is initialize correctly. The second one return this error

Error:
listen EADDRINUSE: address already in use \\.\pipe\FlexsimServerRegistrationPipe
Error: listen EADDRINUSE: address already in use \\.\pipe\FlexsimServerRegistrationPipe
    at Server.setupListenHandle [as _listen2] (node:net:1855:21)
    at listenInCluster (node:net:1920:12)
    at Server.listen (node:net:2025:5)
    at Object.runServer [as run] (C:\Program Files (x86)\FlexSim Web Server 22 - CV\webserver\server.js:356:22)
    at runServer (C:\Program Files (x86)\FlexSim Web Server 22 - CV\webserver\index.js:125:16)
    at Object.<anonymous> (C:\Program Files (x86)\FlexSim Web Server 22 - CV\webserver\index.js:129:5)
    at Module._compile (node:internal/modules/cjs/loader:1376:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1435:10)
    at Module.load (node:internal/modules/cjs/loader:1207:32)
    at Module._load (node:internal/modules/cjs/loader:1023:12)


There was a Problem with the FlexSim WebServer.
Press Enter to Exit.

I suppose that it isn't supported by webserver, but I need to confirm it. Do you have any workaround?

You can reproduce the problem in this easy way:

install webserver 21.0 and configure it;
install webserver 22.2 and configure it;
run the webserver 21.0 (should work correctly);
run the webserver 22.2 (shoudn't work);

I hope to find a solution!

Re: Run multiple webserver instance

joerg_vogel_HsH — Tue, 14 May 2024 08:42:16 GMT

@Alessio Merlo, You need probably a different setup to get access to your webserver on a different port or a second virtual internet address.

"address already in use"

Re: Run multiple webserver instance

amerloQ2XZU — Tue, 14 May 2024 08:51:18 GMT

Thanks @Joerg for quick reply! But the port is not the problem.

When I use the same port the error is:

Error:
listen EADDRINUSE: address already in use :::8081
Error: listen EADDRINUSE: address already in use :::8081
    at Server.setupListenHandle [as _listen2] (node:net:1872:16)
    at listenInCluster (node:net:1920:12)
    at Server.listen (node:net:2008:7)
    at Object.runServer [as run] (C:\Program Files (x86)\FlexSim Web Server 22 - test\webserver\server.js:578:19)
    at runServer (C:\Program Files (x86)\FlexSim Web Server 22 - test\webserver\index.js:125:16)
    at Object.<anonymous> (C:\Program Files (x86)\FlexSim Web Server 22 - test\webserver\index.js:129:5)
    at Module._compile (node:internal/modules/cjs/loader:1376:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1435:10)
    at Module.load (node:internal/modules/cjs/loader:1207:32)
    at Module._load (node:internal/modules/cjs/loader:1023:12)
 
 
There was a Problem with the FlexSim WebServer.
Press Enter to Exit.

Totally different message!

I suppose that the problem is in runServer() function where the server defines the REG_PIPE_PATH. I tried to change the path, the server starts, but then nothing more works.

function runServer() {
    // registration pipe
    REG_PIPE_PATH = "\\\\.\\pipe\\FlexsimServerRegistrationPipe";
    registrationPipe = net.createServer(function(stream) {
        stream.on('data', function(message) {
            var parsedMessage = (message + "").split(",");
            var pid = parsedMessage[0];
            for(var i = 0; i < instances.length; i++) {
                if(instances.proc.pid == pid) {
                    // Store the instance's version before registering
                    if(parsedMessage.length > 1) {
                        instances.version = parsedMessage[1];
                    }

                    instances.registered = true;
                }
            }
        });
        stream.write('3.0.0');
    });
    registrationPipe.listen(REG_PIPE_PATH);

Re: Run multiple webserver instance

amerloQ2XZU — Thu, 23 May 2024 10:12:24 GMT

Does anybody help me? @Phil BoBo @Jordan Johnson

Re: Run multiple webserver instance

philboboADSK — Thu, 23 May 2024 13:54:41 GMT

You don't need multiple webservers to support multiple FlexSim versions anymore.

Just specify the path to the Version Selector for the FlexSim program directory in the webserver configuration file:

Re: Run multiple webserver instance

amerloQ2XZU — Thu, 23 May 2024 15:45:56 GMT

Hi @ Phil,

I need to keep alive two different webserver instances because they allow two different workflows from the user perspective. I can't simply switch from one FlexSim version to another one.

My framework is:

- webserver 21.0 with FlexSim 22.0 with a dedicated module and library;

- webserver 22.2 with FlexSim 24.0 with a dedicated module and library;

In the future I will migrate all libraries and modules to the same FlexSim version, but I can't do it now.

Rigth now I would like to different address to reach the server and manage the workflow separately.

Re: Run multiple webserver instance

philboboADSK — Thu, 23 May 2024 15:48:34 GMT

You can do that with the version selector.

If you want to open the "FlexSim 22.0 with a dedicated module and library," then load an fsm that was saved in version 22. It will open that FlexSim.

If you want to open the "FlexSim 24.0 with a dedicated module and library," then load an fsm that was saved in version 24. It will open that FlexSim.

Instead of having to specify a different webserver port for each different FlexSim version, you can specify the FlexSim version to open based on the version saved in the fsm that you are trying to open. That's the point of the version selector.

In the future I will migrate all libraries and modules to the same FlexSim version, but I can't do it now.

You don't need to do that now. If you use the version selector, then the same webserver can open different FlexSim versions with different modules and libraries.

How did you interpret what I said to mean that you would need to migrate all libraries and modules to the same FlexSim version??

Re: Run multiple webserver instance

amerloQ2XZU — Thu, 23 May 2024 16:29:21 GMT

Thanks Phil!

I will test your idea, it should work! I need to create two different models and use FlexSim version selector to open it. Great!

One doubt for the future: when I will migrate both modules and libraries to same FlexSim version (not mandatory now), how I can manage it? Potentially the modules and libraries can be not compatible and then I will have 2 different flexsim.exe for the same version. In this case the selector recognizes just one, is it correct?

As for me will be mandatory to make the modules compatible!

Re: Run multiple webserver instance

philboboADSK — Thu, 23 May 2024 16:35:23 GMT

Right now, the version selector only works with the FlexSim versions installed in Add/Remove Programs, and you can't have multiple copies of the same version installed there.

You would need to modify the webserver's code if you wanted to be able to select between two different FlexSim installs at different locations with the same version number.

If you need such a customized solution, you'll need to customize it yourself. We're not going to deal with such a unique situation.