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<chapter id="plpython">

<title>PL/Python - Python Procedural Language</title>

<para>

This chapter is not fully developed yet.

</para>

<para>

The current version of PL/Python functions as a trusted language only;

access to the filesystem and other local resources are disabled.

Specifically, PL/Python uses the Python restricted execution environment,

further restricts it to prevent the use of the file open call, and

allows only modules from a specific list to be imported. Presently,

that list includes: array, bisect, binascii, calendar, cmath, codecs,

errno, marshal, math, md5, mpz, operator, pcre, pickle, random, re,

regex, sre, sha, string, StringIO, struct, time, whrandom, and zlib.

</para>

<para>

There is discussion on creating an untrusted language variant for a

future release.

</para>

<para>

In the current version, any postgresql error encountered while running

a PL/Python function will result in the immediate termination of that

function by the backend. It is not possible to trap error conditions

using Python try ... catch constructs. For example, a syntax error in

an SQL statement passed to the plpy.execute() call will terminate the

function. This behavior may be changed in a future release.

</para>

</note>

<sect1 id="plpython-install">