The configuration of a log4j appender via log4j configuration file is a static configuration that cannot be disabled/enabled and managed dynamically by an application designer. The programmatic approach will allow an application designer to specify which of the available log4j appenders should be used for the specific application.
It is not necessary Apex should use the predefined log4j appenders only. The log4j events contain useful but the very limited number of properties which values can be printed into output log4j sources. But based on the knowledge of the software product workflow, the custom defined log4j appender can extend a list of predefined output log events properties and, for instance for Apex, return: node, user name, application name, application id, container id, operator name, etc. Also the output log events that are generated by a custom defined log4j appender can be stored and indexed by any type of a full text search database. It will allow the customers and developers to simplify collection of log events statistics and searching/filtering of specific events for debugging and investigation. Thanks, Sergey On Mon, Apr 10, 2017 at 6:34 AM, Vlad Rozov <v.ro...@datatorrent.com> wrote: > +1 Apex engine does not own log4j config file - it is provided either by > Hadoop or an application. Hadoop log4j config does not necessarily meet > application logging requirements, but if log4j is provided by an > application designer, who can only specify what to log, it may not meet > operations requirements. Dev-ops should have an ability to specify where to > log depending on the available infrastructure at run-time. > > It will be good to have an ability not only specify extra log4j appenders > at lunch time, but also at run-time, the same way how log4j logger levels > may be changed. > > Thank you, > > Vlad > > On 4/9/17 23:14, Priyanka Gugale wrote: > >> We can always write a custom appender and add it by changing root appender >> in log4j config file. Can you explain how adding appender grammatically >> would help? >> >> -Priyanka >> >> On Sun, Apr 9, 2017 at 11:50 AM, Sanjay Pujare <san...@datatorrent.com> >> wrote: >> >> Please give some examples and/or use cases of this programmatic log4j >>> appender. >>> >>> On Fri, Apr 7, 2017 at 8:40 PM, Sergey Golovko <ser...@datatorrent.com> >>> wrote: >>> >>> Hi All, >>>> >>>> I'd like to add supporting of a custom defined log4j appender that can >>>> be >>>> added to Apex Application Master and Containers and be configurable >>>> programmatically. >>>> >>>> Sometimes it is not trivial to control log4j configuration via log4j >>>> properties. And I think the having of the approach to add a log4j >>>> >>> appender >>> >>>> programmatically will allow the customers and developers to plugin their >>>> own custom defined log4j appenders and be much flexible for streaming >>>> and >>>> collection of Apex log events. >>>> >>>> I assume to provide generic approach for definition of the programmatic >>>> log4j appender and to pass all configuration parameters including a name >>>> >>> of >>> >>>> the Java class with implementation of the log4j appender via system >>>> >>> and/or >>> >>>> command line properties. >>>> >>>> Thanks, >>>> Sergey >>>> >>>> >
