I have a similar question (importing cx_Oracle, but not related to
cron). I would like to use solution #2 below and it does not work. If
I set LD_LIBRARY_PATH before running python, it works. If I try to set
it via os.environ, it does not work.
I have tried this in an interactive Python shell. I can print the
value of os.environ["LD_LIBRARY_PATH"] and it is correct, but the
import fails. The cx_Oracle.so file is found, but when it tries to
load the necessary Oracle library (libclntsh.so.9.0), I get the
message:
ImportError: libclntsh.so.9.0: cannot open shared object file: No
such file or directory
Is there something else I have to do when changing os.environ before
trying the import?
Well, all the oracle stuff is installed in /usr/lib/oracle on my computers
(or /usr/share/oracle ... depends when and how I installed it),
but I also always make the symbolic links in /usr/lib too.
I guess once Python is started (and the C level library loader) you can't
change LD_LIBRARY_PATH anymore.
What I ussually set in os.environ is ORACLE_HOME because the oracle library
still needs to find some additional files too.
BTW cx_Oracle seems to only need /usr/lib/libnnz10.so
and /usr/lib/libclntsh.so.10.1 but I also have these links in /usr/lib:
libclntsh.so -oracle/lib/libclntsh.so*
(this is a link to the .so.10.1 file)
libclntsh.so.10.1 -oracle/lib/libclntsh.so.10.1*
libnnz10.so -oracle/lib/libnnz10.so*
libocci.so -oracle/lib/libocci.so*
(this is a links to the .so.10.1 file
libocci.so.10.1 -oracle/lib/libocci.so.10.1*
libociei.so -oracle/lib/libociei.so*
This is with oracle instant client 10 libraries.
>These environment variables are important for running any programs that
use the oracle client libraries. The problem you have is that when you
run the script from cron these environment variables are not set.
Now, there are several ways how to handle this:
1. create a shell script that you call from cron, and it it set the
environment variables and then call you python program
2. modify the environment in your python program (via os.environ) and
then import cx_Oracle
3. modify your system so that no environment variables are neccesseary -
actually this is not possible, but what I have is, symbolic links
in /usr/lib to the libraries in $ORACLE_HOME/lib, thus I don't need the
LD_LIBRARY_PATH variable, and the only other variable I need is the
ORACLE_HOME, which is /usr/share/oracle on my system and it contains
bin/ install/ lib/ network/ ocommon/ oracore/ rdbms/ sqlplus/
--
damjan
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damjan