I have mixed feelings about that. Every filter I have created that clears the
ThreadContext at the end also injects values into the ThreadContext at the
beginning of the request, just as the example at
http://logging.apache.org/log4j/2.x/manual/eventlogging.html
<http://logging.apache.org/log4j/2.x/manual/eventlogging.html> does. So if you
were going to create a filter you would also want to provide a method to do the
setup, so your filter code would look something like:
public void doFilter(ServletRequest servletRequest, ServletResponse
servletResponse, FilterChain filterChain throws IOException, ServletException {
setupRequest(servletRequest, servletResponse);
filterChain.doFilter(servletRequest, servletResponse);
ThreadContext.clear();
}
public void setupRequest(servletRequest, servletResponse) {
}
But the only value this really has is the one line that was added to clear the
ThreadContext. Is that really much of a “convenience”?
Ralph
> On Apr 17, 2018, at 6:29 AM, Gary Gregory <[email protected]> wrote:
>
> Should we provide a stock Log4j filter that does that? A nice convenience.
>
> Gary
>
> On Mon, Apr 16, 2018 at 10:01 PM, Kevin Jung <[email protected]> wrote:
>
>> Thanks Remko and Ralph for the information. I thought of clearing in a
>> filter, but somehow I thought there might be a clean up mechanism already
>> because using ThreadContext in Tomcat is a quite common thing. But that
>> was just my assumption. I agree that it's better to *clear explicitly*.
>>
>> Thanks,
>> Kevin
>>
>> On Mon, Apr 16, 2018 at 8:32 PM, Ralph Goers <[email protected]>
>> wrote:
>>
>>> See the example at http://logging.apache.org/
>>> log4j/2.x/manual/eventlogging.html <http://logging.apache.org/
>>> log4j/2.x/manual/eventlogging.html>. You will see the call to clear the
>>> ThreadContext. It does indeed use a filter.
>>>
>>> Ralph
>>>
>>>> On Apr 16, 2018, at 7:01 PM, Kevin Jung <[email protected]> wrote:
>>>>
>>>> Hello,
>>>>
>>>> I am using Log4j 2 ThreadContext with Tomcat. I wonder if I need to
>>> clear
>>>> ThreadContext at the end (or start) of HTTP request in order to avoid
>> the
>>>> context data being carried over to next HTTP request processing.
>>>>
>>>> I was assuming that thread context is cleared when Tomcat thread is put
>>>> back in the thread pool and when a Tomcat thread starts processing new
>>> HTTP
>>>> request, it starts with an empty thread context, nothing carried over
>>> from
>>>> the previous HTTP request. But that's my assumption, I want to make
>>> sure I
>>>> do not need to clear at the end, like using a servlet filter. Or
>> should
>>> I
>>>> use CloseableThreadContext to avoid carrying over among HTTP requests?
>>>>
>>>> Thanks,
>>>> Kevin
>>>
>>>
>>
