On 11/02/2020 13:56, Claude Warren wrote:
All the code is SLF4J isn't it? So this is just about what implementation
of logging we will ship with various application packages like fuseki.
WARs should probably not include an implementation as many larger servers
(e.g. Websphere) manage the logging for the applications that use standard
logging frameworks.
slf4j is the API called by Jena code - it needs a provider to turn
logging calls into logging output. The provided needs configuration.
In Tomcat at least, the servers system logging and the applications
logging is separated by design:
https://tomcat.apache.org/tomcat-8.5-doc/logging.html
Tomcats own logging, and javax.servlet.ServletContext.log(...) go to the
internal Tomcat logging machinary. Tomcat provides a default enhanced
JUL but it is still limited. That's only in a webapp container.
The application is free to provide its own logging and it should do so -
otherwise the output isn't separated from the system logs.
Fuseki has its own logging (multiline) for the entire request cycle. It
also has NCSA request logging - standard and tools grok it but less
helpful for details. Noi query string, no body, so the query itself
isn't recorded in the NCSA log.
https://en.wikipedia.org/wiki/Common_Log_Format
Andy
Claude
On Tue, Feb 11, 2020 at 1:29 PM Andy Seaborne <[email protected]> wrote:
Summary:
* Replacing log4j1 in logging for Fuseki will affect some users.
log4j1 is well past its end of life. There is a CVE on log4j1 - no
impact directly on Jena but a nudge to advance on JENA-1005
The CVE is for using socket server for receiving log events from other
machines. Jena does not use it, and it would be the user who configured
any use of it. As everything in log4j1 is in the single jar, shipping
that jar ships the socket server and it shows up in static security scans.
So - what does it take to get off log4j1 and what to switch to?
Uses of logging output:
* Fuseki has logging setup code with internal defaults
* jena-cmds uses logging with internal defaults
* Testing - Jena needs some logging provider to run during tests. Also,
some testing wants to dynamically adjust logging (e.g. suppress warnings
when expected)
* jena-jdbc ??
PR#690 makes the testing independent of logging provider by using the
jena-base logging setup code to make dynamically adjusting logging
independent of the logging provider. It does not change the use of log4j1.
The tests use whatever is setup in /pom.xml as a <scope>test dependency.
That's not ideal because it makes it hard to have different logging
choices for different usages in Jena but it does remove duplicating a
<dependency> in each module. (Is there a better way?).
The crunch is Fuseki because a change of logging is change of existing
logging configurations. It also makes a choice for tests the same as
Fuseki because you can't undepend on something from the parent as far as
I can see, and if Fuseki adds logging to its <scope>runtime, there are
two logging providers and slf4j issues warnings.
The simple solution is use log4j2 in the test suites. The alternative is
put a <dependency> in each module, removing it from /pom, the test can
be JUL (and cmds?), and Fuseki server logging log4j2.
log4j2 has a properties-like configuration format (as well as
XML, YAML, and JSON). For installations that use the default logging
setup (formatted, to stdout), there will be be no change.
My guess is that only few installations do change the default setup but
I know of installations that do. That includes one where the logs are
sent to Linux, syslog and then collected across a cluster. JUL
(java.util.logging) doesn't have many connectors; log4j does.
While the command line tools do look for a local log4j.properties, I
don't know of any usage. The limited logging (e.g. tdb loaders) is used
more for a convenient way to control formatting and switch on/off. The
parsers do log which helps in library and command line use.
FYI: there is a slf4j 1.8 that switches to using ServiceLoader. It is at
1.8.0-beta4. There is also a slf4j 2.0.0, currently 2.0.0-alpha1 that
adds a fluent API for log messages. From what I read, existing normal
logging code is binary compatible.
So Fuseki has to change, some (not all) users affected.
Fuseki (servers, not WAR?) choice is log4j2 or other full-featured system.
Ideally, jena-cmds is JUL just from the footprint reduction but can be
log4j2.
Andy
