It seems to me that I found the answer (was googling for two hours and found nothing, then used forum search and voila):

1. Declare a class which inherits Ens.Production:

Class My.Production Extends Ens.Production
{

XData ProductionDefinition
{
<Production Name="My.Production" TestingEnabled="true" LogGeneralTraceEvents="true">
  <Description></Description>
  <ActorPoolSize>1</ActorPoolSize>
</Production>
}
}

2. And launch:

Set isProductionRunning = ##class(Ens.Director).IsProductionRunning("My.Production")
If isProductionRunning = 0 {
            Set sc = ##class(Ens.Director).StartProduction("My.Production")
}

Ended up with a compromise 😊 Just replaced <transform> with a <call> and delegated that transform to BO 

> What parameter are you trying to change?

My subclassed Transform calls some external web service and I want to  allow a user configure that web service settings (url-port-ssl-etc) by clicking on the business process <transform> element. Also, it is crucial that such a transformation cannot be delegated to BO. So anyway, thank you, it is fine if I move settings to BP, but it is not that elegant :(

Perfect, thanks a lot

Got it! Now I'm struggling with adding a value to that array. Would it be correct?

set arr(arr + 1) = value

Thanks Robert. 

> args = number of params

Arrays in IRIS are counterintuitive 😥

Here it is:

Class MyHL7HTTPService Extends EnsLib.HL7.Service.HTTPService
{

Method OnAdapterHTTPResponse(
    ByRef pStatus As %Status,
    ByRef pHTTPResponseStatus As %String,
    ByRef pBodyLen As %Integer,
    ByRef pResponseBodyStream As %Stream.Object,
    ByRef pMainResponseHeader As %String,
    ByRef pHeaderExtra As %String)
{
    set pHeaderExtra = pHeaderExtra _ "Access-Control-Allow-Origin: *"_ $char(13) _ $char(10) 
                                    _ "Access-Control-Allow-Headers: *" _ $char(13) _ $char(10) 
                                    _ "Access-Control-Allow-Methods: *" _ $char(13) _ $char(10)
}

}

I need to find a reason of a performance bug in the source code of the original class :) 

Great answer! And yes, I badly need that for testing!

Thanks, I caught your idea but no, IIS is not a cause, although the issue exists in Windows but not in Linux

I'm using Postman, the default Accept header value was */*, then according your advice I tried application/json, then application/fhir+json, both not working, IRIS still produces HTML

<div id="content">
        <div class="content-container">
            <fieldset>
                <h2>500 - Internal server error.</h2>
                <h3>There is a problem with the resource you are looking for, and it cannot be displayed.</h3>
            </fieldset>
        </div>
    </div>

I have ended up with Hyper-V and Ubuntu but thanks 

Thanks but I doubt it's a license issue. The IRIS installer creates another log in C:\Windows directory, and it also contains no useful information. At some point the installation process just hangs as well as the log file stops growing.

UPD1: launched the installation package via the "Run as administrator" menu item. Now the messages.log file contains the following diagnostics info:

- on Ryzen 3900 - the processor has too many cores which is not allowed by Community edition license

- on Athlon 3000G the error message is less informative: `11/06/22-01:06:28:788 ( 5200) 3 irisctl.dll (error during startup):(289) IRIS failed to start.  IRIS Control Process terminated abnormally (exit code = 0).`

Great, thanks a lot, works perfectly!

I know about messages.log, but in my case it's pretty short (~2kb) and contains no useful trace info :( There are workarounds with Docker and VMs, both approaches work

Laptop - Windows 11 

AMD workstations - Windows 10 Home (official OEM, with fresh updates)