Re: [ebxmlms-develop] Variable interpolation in configuration

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Dear Jason,
OK, we have added your patch to the source tree. Thanks for your effort.
Regards, -Patrick

----- Original Message -----
From: "Jason van Zyl" <ja...@ze...>
To: <ebx...@li...>
Sent: Tuesday, February 04, 2003 4:28 PM
Subject: Re: [ebxmlms-develop] Variable interpolation in configuration

> On Tue, 2003-02-04 at 03:02, Patrick Yee wrote:
> > Hi Jason,
> >
> > Thanks for the suggestion. However, after some discussion, we think the
> > change is not quite necessary because:
> >
> > 1. Hermes deployment is not a day-to-day work. We expect the
configuration
> > will not be changed frequently. So using static values will be adequate
for
> > most of the time.
>
> I have integrated Hermes into our application server which might be
> installed anywhere in the filesystem on machines with various operating
> systems. I need to be able to dynamically configure Hermes because I
> don't know where the installation is going to land. Something like
> "/tmp/hermes" might possibly work on unix machines but it certainly
> wouldn't work on other platforms. In addition, we like to keep all the
> files for our application grouped together. We don't care where they are
> grouped together. Without interpolation I can't provide the type of
> installation that we require. I do not know ahead of time where our
> clients will install our product.
>
> > 2. In the scenario that you suggest, we are only transferring the
> > "hard-wiring" of property values from Hermes's configuraiton file to the
> > application server's configuration files.
>
> We don't hardwire anything. Everything is dynamic. Our application
> server works from the directory where it is installed. We don't know
> where ahead of time but when our container starts up it gathers
> information from the environment and makes that available to all our
> components running in the container.
>
> > There is anyway a file which
> > should "hard-wire" the property values, which is not portable from file
> > system to file system. Under this basis, we believe to "hard-wire" the
value
> > in Hermes property file is acceptable.
>
> You can't make an installer with Hermes in it without variable
> interpolation or some sort of runtime configurability. Variable
> interpolation is a very simple solution to the general problem of
> relocatable applications.
>
> > 3. We need some extra exception handling when trying to interpolating a
> > non-existing system property. In this angle, this makes the
configuration
> > more complicated. Our design philosophy is to keep every behaviour
> > deterministic. Of course, we may not be doing very well, but at least
that
> > is our direction.
>
> I can add any exception handling if I missed something, more than happy
> to make things as robust as possible.
>
> Allow a form of runtime configurability has no down side and is of great
> value to users trying to integrate Hermes into various products. It
> allows Hermes to be used in unforseen circumstances. For example the way
> I have Hermes working now inside our container it could be stopped,
> package up because it's all in a single directory, moved to another
> machine in a completely different path, started up and Hermes would work
> just as it did. This might need to be done because of hardware failure
> or just because someone wants to move it. Providing this kind of
> flexibility, I believe, is well worth any extra work that needs to be
> done internally in Hermes. And I volunteer to do the work :-) For me
> this feature is essential for the operation of our container and
> necessary to satisfy our user requirements.
>
> > What do you think? Let's discuss about this. Thank you for your
continuous
> > input.
>
> Happy to help, you've saved me months of development time so I'll
> contribute however I can.
>
> > Regards, -Patrick
> >
> > ----- Original Message -----
> > From: "Jason van Zyl" <ja...@ze...>
> > To: <ebx...@li...>
> > Sent: Sunday, February 02, 2003 12:45 AM
> > Subject: [ebxmlms-develop] Variable interpolation in configuration
> >
> >
> > > Hi,
> > >
> > > I've added variable interpolation in the XMLProperty.java file so that
I
> > > can more easily integrate Hermes into our application server. The
> > > interpolation only works with system properties with the "ebxmlms"
> > > prefix.
> > >
> > > So I'm setting a system property in our application server with:
> > >
> > >   <system-properties>
> > >     <property name="ebxmlms.basedir" value="${plexus.work}/ebxmlms"/>
> > >   </system-properties>
> > >
> > > And then I can do something like the following in the
> > > msh.properties.xml:
> > >
> > > <?xml version="1.0" encoding="UTF-8"?>
> > > <Property>
> > >   <MSH>
> > >     <Log>
> > >       <!-- "JDK" or "LOG4J" -->
> > >       <UseLogger>LOG4J</UseLogger>
> > >       <!-- empty path: user.home -->
> > >       <LogPath>${ebxmlms.basedir}</LogPath>
> > >       <LogFile>msh.log</LogFile>
> > >       ...
> > >     </Log>
> > >   </MSH>
> > > </Property>
> > >
> > > This makes it very easy for integrators, like myself, to move the
> > > application server around the filesystem and have things completely
> > > self-contained.
> > >
> > > So this means we can deploy Hermes and not have to deal with absolute
> > > paths which is essential for our installation setup.
> > >
> > > You can find the file here:
> > >
> > > http://www.apache.org/~jvanzyl/ebxmlms/XMLProperty.java
> > >
> > > I'll send changes in whatever form you like. Do you prefer patches or
> > > whole files?
> > >
> > >
> > > --
> > > jvz.
> > >
> > > Jason van Zyl
> > > ja...@ze...
> > > http://tambora.zenplex.org
> > >
> > > In short, man creates for himself a new religion of a rational
> > > and technical order to justify his work and to be justified in it.
> > >
> > >   -- Jacques Ellul, The Technological Society
> > >
> > >
> > >
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> >
> >
> >
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> --
> jvz.
>
> Jason van Zyl
> ja...@ze...
> http://tambora.zenplex.org
>
> In short, man creates for himself a new religion of a rational
> and technical order to justify his work and to be justified in it.
>
>   -- Jacques Ellul, The Technological Society
>
>
>
> -------------------------------------------------------
> This SF.NET email is sponsored by:
> SourceForge Enterprise Edition + IBM + LinuxWorld = Something 2 See!
> http://www.vasoftware.com
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