Ruby IO on brand new xserve with Leopard Server

Rails
1

Hi

I’m using princexml pdf generation in one of our apps and bump into
this very weird problem. On our ubuntu box and local machines
(MacBook Pro) pdfs are generated flawlessly. On the production xserve
(running the rails app in production mode on a mongrel cluster), a
2.8 GHz Quad-Core Intel Xeon, strange things start happening. The
following sections give back nil values in production, but valid
values in development (script/console, …) even on the xserve itself:

 @exe_path = `which prince`.chomp

 # Actually call the prince command, and pass the entire data

stream back.
pdf = IO.popen(path, “w+”)
pdf.puts(string)
pdf.close_write
pdf.gets(nil)

When i call the commands manually from the console, they work, giving
back a valid PDF file. In production mode, both are nil, bombing the
application. It’s almost as if the ruby code is too fast to wait for
the system call result. I’ve tried just about everything possible,
even going as far as putting delays between each command, with no
result whatsoever.

Has anyone experiences similar issues either on leopard server
(default ruby bundled with the system) or an xserve?

Thanks in advance

Peter

2

On Feb 3, 2008, at 6:43 AM, Peter De Berdt wrote:

@exe_path = `which prince`.chomp

# Actually call the prince command, and pass the entire data

stream back.
pdf = IO.popen(path, “w+”)
pdf.puts(string)
pdf.close_write
pdf.gets(nil)

I don’t know if this was a transcription problem or if this is the
actual code you run, but I can’t see how it would work on any
platform. You set @exe_path but then don’t use it in IO.popen().

Another thing to look at is permissions. Does the process owner on the
xserve have permissions to WRITE to the specified path? It might be
failing silently on the xserve.

cr

3

On 03 Feb 2008, at 17:39, Chuck R. wrote:

# Actually call the prince command, and pass the entire data

stream back.
pdf = IO.popen(path, “w+”)
pdf.puts(string)
pdf.close_write
pdf.gets(nil)

I don’t know if this was a transcription problem or if this is the
actual code you run, but I can’t see how it would work on any
platform. You set @exe_path but then don’t use it in IO.popen().

Those are two sections of code. Here’s the complete code:
http://sublog.subimage.com/articles/2007/05/29/html-css-to-pdf-using-
ruby-on-rails

The prince class can be seen here: Parked at Loopia

Another thing to look at is permissions. Does the process owner on the
xserve have permissions to WRITE to the specified path? It might be
failing silently on the xserve.

It doesn’t write anything, it just writes a command to the command
line as far as I see. (Well, it does, to STDIN). Unless I’m missing
something in the prince class.

Best regards

Peter De Berdt