On May 11, 2006, at 8:29 AM, Joe Bohn wrote:
Thanks for the quick response Jeff.
I like the idea of a "system patch" location in the classpath where
we can pick up patches for anything we might include in a geronimo
assembly.
I think this "system patch" idea will only work in environments with
only one classloader, i.e. not geronimo. The problem is that the
patched classes need to get into the correct classloader, "before"
the normal versions. We'd need a patch directory for each module.
I also think any solution that relies on the order of stuff in a
classpath is inherently unstable and unreliable.
Basically I think this is a terrible idea and we should avoid it at
all costs. I think instead we should use our new version
independence and replace jars with patched jars with slightly higher
version numbers. IIUC this is what you propose doing below. This
should not require removing the standard tomcat jars: the hight
version number should be enough to get the correct version picked up.
thanks
david jencks
I too was confused by the tomcat recommendation but it does seem
that they have a strategy for addressing necessary changes with
minimal interference in tomcat. I have also noticed some things
that make me wonder if my local tomcat build of 5.5.15 really does
match the official 5.5.15 build. For example, the only source for
5.5.15 that I could find was a zip file rather than a svn branch or
tag. I am not able to build from the unpacked zip without making a
change to move the contents of jasper/jasper2 into the jasper
directory itself. And the version that is displayed when I hit
tomcat with my rebuilt image is 5.5 rather than 5.5.15 as with the
official image.
Until we figure out the correct approach for Geronimo I'm thinking
of using a compromise solution. The changes I need in tomcat
result in 4 of the 13 tomcat jars getting rebuilt. Rather than
replacing all of the tomcat jars with my local build I have
verified that replacing just the 4 changed jars appears to work
fine. I'm hoping this hybrid solution keeps most of the official
tomcat image and our local changes. I haven't noticed any
problems. Assuming the source is mostly identical (apart from our
changes) does anybody know of a reason that I should definitely not
take this approach?
Joe
Jeff Genender wrote:
Ultimately, we probably would need to somehow build a "patch"
directory
or lib directory where we can ensure the URLClassLoader picks that up
before all other classes. I think this is probably a good idea to
have
as well, so that we could release "service paks" or patches. I
would be
interested in others' thoughts on this, but I think this would be
a nice
feature to have.
Right now I think your only choices are to either hard set a
classpath
to be sure the patches get picked up first or build a hacked Tomcat
version, or rebuild Tomcat. Dain or David Jencks may be able to
verify
if the classpath solution would work or not as I have not dug into
the
new G classloaders to know if this would even be possible.
The best solution right now may be to just build TC. I am a little
confused as to why the TC guys say not to build the Tomcat from
source
(after its hacked). It seems like just an ant build script, so I
don't
understand why this is being discouraged. This way you can
replace the
Tomcat jars in the repo and you are good to go.
Jeff
Joe Bohn wrote:
Jeff,
I am working with a user that is moving some applications from
tomcat to
geronimo. Due to some problems they have had to modify tomcat
source.
I was chatting with jasonb on the tomcat irc channel and he
recommended
that we only build the classes rather than rebuilding all of
tomcat. He
discouraged rebuilding all of tomcat because there are many
permutations
that can result in different build images and we should run with
as much
of the official tomcat build as possible to avoid problems. He also
indicated that Tomcat's directory structure provides a place to put
these "patch classes" in CATALINA_HOME/server/classes .
Is there a similar place that we can put classes when tomcat is
running
under geronimo to have them picked up? Adding the tomcat classes
to our
new sharedlib doesn't seem to be the right place because it would
require a dependency from the tomcat config on sharelib. The net
result
would be that all tomcat apps would potentially pick up user classes
added in sharedlib even if the user only intended these classes
for some
subset of the apps.
Joe
--
Joe Bohn
joe.bohn at earthlink.net
"He is no fool who gives what he cannot keep, to gain what he
cannot lose." -- Jim Elliot
