[logback-dev] [JIRA] Updates for LOGBACK-1527: TeeFilter prints stack traces of uncaught exceptions to the standard erorr stream

[QOS.CH (JIRA)]

logback / LOGBACK-1527 [Open]
TeeFilter prints stack traces of uncaught exceptions to the standard erorr stream

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https://jira.qos.ch/browse/LOGBACK-1527

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 Issue created
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Gediminas Rimsa created this issue on 02/Oct/20 6:51 PM
Summary:              TeeFilter prints stack traces of uncaught exceptions to the standard erorr stream
Issue Type:           Bug
Affects Versions:     1.2.3
Assignee:             Logback dev list
Components:           logback-access
Created:              02/Oct/20 6:51 PM
Environment:
  Logback 1.2.3
  
  Spring boot webapp, with Logback configured to log to ConsoleAppender
Priority:             Minor
Reporter:             Gediminas Rimsa
Description:
  h2. Problem
  
  In a webapp uncaught exceptions are handled (logged) by the servlet container (Tomcat in our case).
  
  However, Logback `TeeFilter` has the following code:
  {code:java}
  try {
      // ... (omitted)
      filterChain.doFilter(teeRequest, teeResponse);
      // ... (omitted) 
  } catch (IOException e) {
      e.printStackTrace();
      throw e;
  } catch (ServletException e) {
      e.printStackTrace();
      throw e;
  }
  {code}
  This causes the stack trace to appear twice in the console (once logged by TeeFilter, and once by Tomcat).
  h2. Proposed solution
   # Remove `e.printStackTrace();` statements from `TeeFilter` - it has no responsibility of printing stack traces of exceptions it can not handle
   # Also replace `System.out.println` statements with logging to SLF4J API at INFO level
  
  I'd be happy to raise a PR for this if a new version of logback-access would be released soon after the fix.


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