Class::DBI::Oracle environment variable issue

mildside has asked for the wisdom of the Perl Monks concerning the following question:

Is it possible to set environment variables for Oracle inside perl for use with Class::DBI::Oracle? I'm getting an error from DynaLoader saying it cant find a library. My code works fine if I set LD_LIBRARY_PATH in my shell and then call the perl program, but I want to know if I can do it inside the perl. I've tried stuff along the lines of:

BEGIN
{
  $ENV{LD_LIBRARY_PATH} .= ":/users/oracle/product/9.2.0/lib";
  $ENV{ORACLE_HOME}    ||= "/users/oracle/product/9.2.0";
}

package MyDatabase::DBI;
use strict;

use base 'Class::DBI::Oracle';

# connect to the database.
MyDatabase::DBI->connection('dbi:Oracle:fred', 'wilma', 'barney');

# more code to follow etc...
[download]

But this does not seem to work. Any ideas?

Thanks, mildside.

Comment on Class::DBI::Oracle environment variable issue Download Code

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Re: Class::DBI::Oracle environment variable issue by herveus (Prior) on Nov 22, 2005 at 14:51 UTC
Howdy! Given your findings, what you need to do in the BEGIN block is something along the following lines: `BEGIN { if ($ENV{LD_LIBRARY_PATH} doesn't contain the necessary thingy and $ENV{ORACLE_HOME} doesn't contain the necessary thingy) { set $ENV as above exec $0, @_; } }` [download] This re-executes the script, but the environment has been changed. Double check the syntax for all the bits; the concept of "diddle %ENV and exec myself" will do the trick. I know I had to do stuff like that with Sybase. yours, Michael	[reply] [d/l]
Re^2: Class::DBI::Oracle environment variable issue by mildside (Friar) on Nov 22, 2005 at 23:01 UTC
Thanks herveus, this has worked a treat! I changed the 'and' to an 'or', and slightly changed the 'exec', but otherwise followed your example pretty closely. My new BEGIN block follows: `BEGIN { if (!defined($ENV{'ORACLE_HOME'}) \|\| !defined($ENV{'LD_LIBRARY_PA +TH'})) { $ENV{'ORACLE_HOME'} = "/users/oracle/product/9.2.0"; $ENV{'LD_LIBRARY_PATH'} = $ENV{'ORACLE_HOME'} . "/lib"; exec($^X, $0, @ARGV); } }` [download] Thanks again, mildside	[reply] [d/l]
Re: Class::DBI::Oracle environment variable issue by VSarkiss (Monsignor) on Nov 22, 2005 at 15:36 UTC
The root of the problem is that by the time your program begins execution, `LD_LIBRARY_PATH` has already been used. Changing it will only affect any child processes, not the program's process itself. Your options are to either do the "exec myself" trick herveus mentions above, or to wrap a second program (Perl, or shell as you're using now) around your main program. Do not rebuke them with harsh words ... but rather lead them gently - with URLs - so that they may learn wisdom.	[reply] [d/l]
Re^2: Class::DBI::Oracle environment variable issue by mildside (Friar) on Nov 22, 2005 at 23:08 UTC
Thanks VSarkiss. I had kind of realised that this was the problem, but had thought maybe there was a way to tell DynaLoader where to look for the library. I even checked the doco and found an array that DynaLoader uses for this purpose, but couldn't get it to do what I want. I suspect that even in this case it is, as you say, too late. In any case, herveus's solution works and I'm happy.	[reply]
Re: Class::DBI::Oracle environment variable issue by ptum (Priest) on Nov 22, 2005 at 05:05 UTC
Are you trying to access environment variables from within a CGI script? Are you using Apache? If "yes" to both of those questions, you need to explicitly pass the environment variables through Apache as described here: http://httpd.apache.org/docs/1.3/env.html. No good deed goes unpunished. -- (attributed to) Oscar Wilde	[reply]
Re^2: Class::DBI::Oracle environment variable issue by mildside (Friar) on Nov 22, 2005 at 05:08 UTC
Thanks for your reply ptum. However, no, this is not a CGI I script, and Apache is not involved.	[reply]