Forum: Ruby $LOAD_PATH and different OSes

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Greg W. (Guest)
on 2008-10-22 10:22
Looking for best practice guidance on dealing with differing paths to
libraries & gems amongst OSes.

I can write some reasonably decent Ruby at this point, but still a
padawan when it comes to really understanding the whole *nix ENV thing.

I get that ruby has some default places it looks, and that I can
manually add paths to $LOAD_PATH, but now I'm starting to develop and
deploy on different OSes, and I find that my dev system finds libs and
gems that my server doesn't find.

I can use symlinks to force common paths, or I can put both dev and
server paths into $LOAD_PATHS, but both of these methods are obviously
hokey. I bet there's a better way, and I bet that somehow it involves
paths in etc/profile file, but just not sure how it all goes together.
Is setting path vars in profile on multiple machines really any better
than setting up symlinks? It's still customizing each box (automation is
my friend I know).

I have at least found #!/usr/bin/env ruby to get past hard coded paths
for that.

dev system = OS X 10.4, servers will be 10.4, 10.5, and sometimes Cent
OS variants.

So, any suggestions for the Right Wayâ„¢ ?

-- gw
Martin B. (Guest)
on 2008-10-22 11:45
(Received via mailing list)
I suggest to use rubygems, even if you don't write libraries or plan to
publish your program.

Your layout then should look something like:
.
|-- bin
|-- lib
|   `-- your_project_name
`-- tests

Now, for all executables that are in 'bin' first line of code:

$: << File.expand_path(File.dirname(__FILE__) + '/../lib')

This allows you to run the development code, but once installed it will
use
the installed files from rubygems.

To deploy, just 'gem install your_project.gem' .. your libs will be
found and
the executables are copied in the right place no matter which OS
(assuming
your gemspec file defines 'bindir' and 'executables').

Martin
Greg W. (Guest)
on 2008-10-22 22:31
Martin B. wrote:
> I suggest to use rubygems, even if you don't write libraries or plan to
> publish your program.

I have considered gems (still unsure how to 'serve' them privately), but
since you brought it up, the scenario that prompted this message was
that it was precisely an installed gem that was causing my problems --
the mysql one.

I installed it on a fresh server and discovered that it was not
automatically being found (but it was being found on my dev box). I
output $LOAD_PATH and AFAICT there were no paths that pointed to any GEM
folders, so I am having to do that manually in my app code.

My own libraries I am not having any problems with, it was the
differences in GEM paths between the OSes that was causing my problem.

-- gw
Michael G. (Guest)
on 2008-10-22 23:04
(Received via mailing list)
On Wed, Oct 22, 2008 at 2:30 PM, Greg W. <removed_email_address@domain.invalid>
wrote:
> automatically being found (but it was being found on my dev box). I
> output $LOAD_PATH and AFAICT there were no paths that pointed to any GEM
> folders, so I am having to do that manually in my app code.
>
Make sure you're doing "require 'rubygems'" at the top of your script
in question.

You could also check the environment variable RUBYOPT, you can use it
to automatically require rubygems.

RUBYOPT='rubygems'

HTH,
Michael G.
Greg W. (Guest)
on 2008-10-22 23:18
Michael G. wrote:
> On Wed, Oct 22, 2008 at 2:30 PM, Greg W. <removed_email_address@domain.invalid>
> wrote:
>> automatically being found (but it was being found on my dev box). I
>> output $LOAD_PATH and AFAICT there were no paths that pointed to any GEM
>> folders, so I am having to do that manually in my app code.
>>
> Make sure you're doing "require 'rubygems'" at the top of your script
> in question.

Aha! That puts some pieces together. Thanks.

-- gw
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