[ogsa-wg] Re: [cddlm] Basic POSIX Component & template draft

[Steve Loughran]

Hiro Kishimoto wrote:
> Hi Steve,
> 
> Your file & filesystem components are very good. They are what
> I am looking for. 

I'd say they are a start. What is important is to have things that are 
generally useful yet at a high enough level to avoid a deployment 
descriptor evolving into a workflow script listing every single pre-and 
post- staging operation that takes place. The TempDir component example 
is a good one -it not only creates a temporary directory, it cleans it 
up on closedown. You could imagine an extension which added purging of 
files over 72 hours old to keep transient directories from overflowing 
on a long-running deployment. The higher level the components are, the 
more useful declarative deployment becomes. Otherwise you are writing 
shell scripts in XML, which is nearly the worst of all possible worlds.

The other goal is to integrate with all the other work, not, as Dave 
Berry indirectly hints, try and repeat the work. I'd envisage staging 
components that set up paths to stuff in ACS repositories or other data 
sources. Its not the job of the deployment descriptor to say how that 
stuff gets close, only that at deployment time, the deployed program 
needs to know the path to where the stuff they want is. All we need is 
re-usable components that make use of all the file system/staging/data 
stuff being done to set things up right at deploy time, clean up when 
terminating, and to check for valid configurations and health at deploy 
time.

>One more question I have in my mind is how to
> set user-id, group-id, and permissions to deployed files.
> 

For Java implementations, you wait for Java 6 or execute chmod programs. 
Most irritatingly, Java operations to copy a file inherit back to the 
current defaults, not those of the source file. Over in Ant-land, this 
is a continous source of support calls, right up there with "no easy way 
to work with symlinks" and file case sensitivity problems in terms of 
where Java-on-portable-filesystem's limitations poke through.

-Steve