You bet it does; that's the point! Under the covers, I believe it's simply a thread-local hashmap. Nothing is stored in the loggers the code is using. We just need to be careful to remove the variable from MDC when we're done.
~ David On 12/17/08 3:09 PM, "Ryan McKinley" <ryan...@gmail.com> wrote: but does this work in a multi-threaded environment? if multiple requests are coming in on multiple threads, would it still be accurate? Perhaps that depends on the underlying implementation? adding the core to the MDC within a RequestHandler context seems reasonable and minimally invasive. ryan On Dec 17, 2008, at 2:24 PM, Smiley, David W. wrote: > I propose that MDC or NDC be used instead. I prefer MDC. I've > written some server-side multi-threaded code where each Thread would > run a job and I wanted the job name in the logs. > > http://www.slf4j.org/api/org/slf4j/MDC.html > > At some early point when Solr receives a request, you simply store a > name-value pair which would be "core" and the name of the core for > us. In a finally block, remove it. In a log4j config file, in the > ConversionPattern, put this: %X{core} and this will expand to the > core name. > > Some groovy snippet I wrote: > final MDC_KEY = "OraSeqId" > MDC.put(MDC_KEY, seq.id as String)//must be removed; see finally > > //in-finally > MDC.remove(MDC_KEY) > > ~ David Smiley > > On 12/17/08 2:17 PM, "Erik Hatcher" <e...@ehatchersolutions.com> > wrote: > > > > On Dec 17, 2008, at 12:24 PM, Ryan McKinley wrote: > >> I'm not sure I understand... >> >> are you suggesting that rather then configuring our logger like this: >> static Logger log = LoggerFactory.getLogger(SolrCore.class); >> >> We get the Logger everytime we use it with something like: >> Logger log = LoggerFactory.getLogger(classname+":"+core.getName() ); >> >> That seems like a lot of overhead for marginal gain... > > I'm not up on the logging tips and tricks best practices these days, > but yeah, I was suggesting something like that. There's no rule that > says logging keys be FQCNs.... that's a decent convention for most > cases with a package structure that is well organized and filterable. > In this case having the core name in there as a prefix makes a lot of > sense to me. > > We could provide a LoggerUtils.getLogger(core, clazz) or something > like to keep it DRY and consistent. > > Erik > >
