Olingo v4 + log4j2

Question

I could not find any information about Olingo v4 system logging like spring boot has. Tutorial includes slf4j, so there must be internal logging in framework

   <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-simple</artifactId>
      <version>${slf4j.version}</version>
      <scope>runtime</scope>
    </dependency>

But I was not able to find any occurrences of logging configuration in tutorial or sample code. I want to use log4j2 for logging purposes and I'm expecting specific parameter to be used in web.xml like it works in spring boot

<context-param>
    <param-name>log4jConfiguration</param-name>
    <param-value>log4j2.properties</param-value>
</context-param>

Moreover I found ODataDebugCallback implementation for v2 - Debug Support and Error Handling

But it's for v2 and does not work in v4

Is there any context-param to use or something similar to ODataDebugCallback for logging purposes?

Small case description.

I have created Olingo v4 OData API above data base. One of it key features is dynamic metadata build. It worked fine initially but when I'm creating new table I'm getting

{
    "error": {
        "code": null,
        "message": "OData Library: An exception without message text was thrown."
    }
}

And no catch in OData servlet

        try {
            /*session, storage, handler, edm providers init here*/

            // let the handler do the work
            handler.process(req, resp);
        } catch (Exception e) {
            log.error("Server Error occurred in ODataServlet", e); //app is not getting here
            throw new ServletException(e);
        } finally {
            log.debug("========== Request end ==========");
        }

And my log

[DEBUG] ODataServlet - ========== Request begin ==========
[DEBUG] ODataServlet - Received GET request /myOdataServer.svc/$metadata from 0:0:0:0:0:0:0:1
[DEBUG] JDBCFactory - Opening connection to jdbc:postgresql://host/card_storage
[DEBUG] ODataServlet - ========== Request end ==========

I'm hoping to get more info from framework about error: stack trace, line number, something.

Answer 1

To get the exception trace, You may check the ServerCoreDebugger class.

Basically you need to register DebugSupport to the ODataHttpHandler, and add query parameter like 'odata-debug=json' to your request url to work with the DefaultDebugSupport to get the exception trace from response.

handler.register(new DefaultDebugSupport());