[undertow-dev] pass MDC to worker thread

[Мартынов Илья]

Thank you for your answers. I understand I need to explicitly set MDC in
worker thread. Problem is I cannot modify the codebase of application that
runs on Wildfly. Actually it is a war deployed into Wildfly, and I cannot
re-build it. I want to customize only undertow/wildfly.
The custom handler I add this way runs in IO thread:
/subsystem=undertow/configuration=filter/custom-filter=correlation:add(module="com.ingrammicro.idp.undertow-correlation",class-name=com.ingrammicro.idp.CorrelationHandler)
/subsystem=undertow/server=default-server/host=default-host/filter-ref=correlation:add()

But from stacktrace I see multiple handlers run in worker thread:
handleRequest:43, PredicateHandler (io.undertow.server.handlers)
handleRequest:68, RedirectDirHandler (io.undertow.servlet.handlers)
handleRequest:132, SSLInformationAssociationHandler
(io.undertow.servlet.handlers.security)
handleRequest:57, ServletAuthenticationCallHandler
(io.undertow.servlet.handlers.security)

Also, I can add an expression handler that runs in worker thread:
/subsystem=undertow/configuration=filter/expression-filter=IM_private:add(,expression="path-template('/auth/realms/{realm}/restart-session')
-> ip-access-control(acl={'127.0.0.1 allow', '0:0:0:0:0:0:0:1 allow'})")
/subsystem=undertow/server=default-server/host=default-host/filter-ref=IM_private:add()

Is it possible to add a custom handler to run in a worker thread?



ср, 3 июн. 2020 г. в 10:23, Andrea Di Cesare <andrea at softinstigate.com>:

> If a thread switch occurs the MDC context is lost.
>
> You can attach it to the exchange:
>
> public static final AttachmentKey<Map<String, String>> MDC_CONTEXT_KEY =
> AttachmentKey.create(Map.class);
> ....
> exchange.putAttachment(MDC_CONTEXT_KEY, MDC.getCopyOfContextMap());
> ...
>
> and then restore it in your worker thread:
>
> MDC.setContextMap(exchange.getAttachment(MDC_CONTEXT_KEY));
>
> Hope this helps,
>
>  Andrea Di Cesare
>  Partner at Soft*Instigate* <https://softinstigate.com/>
>  MongoDB Technology Partner
>   <https://sched.co/b2Hz>
>  Via Copernico 38, 20125 Milano (Italy)
>  Mobile: +39 329 737 6417
>  Skype: ujibang
>
>  The company behind *REST*Heart <https://restheart.org>, the NoCoding and
> NoSQL Platform for MongoDB
>
>
> Il giorno mar 2 giu 2020 alle ore 14:57 Мартынов Илья <
> imartynovsp at gmail.com> ha scritto:
>
>> Hello,
>>
>> I've created a handler to fill MDC from incoming request header.
>> public class CorrelationHandler implements HttpHandler
>> {
>>     private HttpHandler next;
>>     public CorrelationHandler(HttpHandler next) {
>>         this.next = next;
>>     }
>>     @Override
>>     public void handleRequest(HttpServerExchange e) throws Exception {
>>         String corr = e.getRequestHeaders().getFirst("IDP-CORR-ID");
>>         MDC.put("corr", corr);
>>         next.handleRequest(e);
>>     }
>> }
>>
>> But most of my processing is done in worker thread and mdc is not passed
>> threre. How to pass it?
>>
>> _______________________________________________
>> undertow-dev mailing list
>> undertow-dev at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/undertow-dev
>
>
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