Hi Ralph, Thank you for elaborating, that makes sense, and I can see how that is useful. Limiting recursion to some small number of levels, as a default controlled by system property (or some other mechanism), still seems like it could be worthwhile, it would close any potential for the issue in 3230 to crop back up elsewhere. Unless it is common to need tens of levels of recursion, it might be nice to disallow it by default.
Den søn. 19. dec. 2021 kl. 17.04 skrev Ralph Goers < [email protected]>: > In my configuration I have > > <properties> > <property name="log_env">${sys:environment:-lab}</property> > <property name="flow_lab">${sys:flow_match:-ACCEPT}</property> > <property name="flow_prod">NEUTRAL</property> > <property name="level_lab">INFO</property> > <property name="level_prod">INFO</property> > </properties> > > <MarkerFilter marker="FLOW" onMatch="${flow_${log_env}}" > onMismatch="NEUTRAL”/> > > This will set the onMatch value to the value of the flow_match system > property in the lab or > ACCEPT if it isn’t set and to NEUTRAL in production. However, with 2.14.1 > this became > unnecessary as one can now do: > > <SystemPropertyArbiter propertyName="env" propertyValue=“lab"”> > <MarkerFilter marker="FLOW" onMatch=“ACCEPT" onMismatch="NEUTRAL”/> > </SystemPropertyArbiter> > > This would only add the filter to the configuration in the “lab” > environment, which is even > better than having a filter defined with both onMatch and onMismatch as > NEUTRAL. > > > Ralph > > > > On Dec 19, 2021, at 3:19 AM, Stig Rohde Døssing <[email protected]> > wrote: > > > > Hi, > > > > The fix for https://issues.apache.org/jira/browse/LOG4J2-3230 looks > like it > > disables recursive interpolation for strings that are not sourced from > the > > log4j configuration. I'm wondering why recursive interpolation is > desirable > > at all, at least as a default? Is it so you can have your config do > > something like $${env:VARNAME} and let the operator specify a pattern in > > VARNAME? > > > > Assuming recursive interpolation is useful at all, is deeply nested > > recursive interpolation useful? Could it make sense to limit recursion > to a > > few levels (e.g. 3 or 5) by default, and let users raise that limit via > > system property if they really need it? I can't think of a case where you > > would want deep nesting, but maybe there's a use case? > > > > Sorry if this is well-trodden ground, I'm just having a hard time > > understanding why this feature exists in its current form. > >
