krbcontext 0.1

A Kerberos context manager

krbcontext does the initialization of credential cache (ticket file) in a kerberos-related context. It provides a context manager that allows developers to put codes, which needs kerberos environment, into a kerberos context.

One important thing is that you should configure /etc/krb5.conf correctly before doing anything with Kerberos.

krbcontext will initialize the credential cache when be invoked each time.

You can use krbcontext with a regular Kerberos user or a service Keytab file. When you work as a regular user, krbcontext prompts you to enter password of your Kerberos account. Whatever in which way, krbcontext accepts a set of default values and specified values.

There are several concept you must know before using krbcontext, principal of user and service, service Keytab file, and credential cache (ticket file). Therefore, the arguments passed to krbcontext are mapped to these concepts.

Usage

Arguments

using_keytab

Specify whether using the service Keytab to initialize the credential cache. Default is False.

kwargs

Specify necessary argument for initializing credential cache. You can pass:

• principal: user principal or service principal

• keytab_file: absolute path of Keytab file

• ccache_file: absolute path of credential cache

Basic

krbcontext can be used as a normal context manager simply.

>>> with krbcontext():
...     # your code here
...     pass

As a regular user

>>> with krbcontext():
...     pass

This is the most simplest way. It uses default values. It gets current effective user name rather than login name, and initialize the default credential cache, /tmp/krb5cc_xxx, where xxx is the current user ID returned by os.getuid method.

Specifying custom values

>>> with krbcontext(principal='[e-mail]',
...                 ccache_file='/tmp/krb5cc_my'):
...     pass
...
>>> with krbcontext(principal='qcxhome',
...                 ccache_file='/tmp/krb5cc_my'):
...     pass

Using service Keytab

>>> with krbcontext(using_keytab=True,
...                 principal='HTTP/[e-mail]'):
...     pass

You can also use default values here except the using_keytab and principal. The default Keytab locates /etc/krb5.keytab, and default credential cache locates /tmp/krb5cc_xxx, like above.

>>> with krbcontext(using_keytab=True,
...                 principal='HTTP/[e-mail]'):
...                 keytab_file='/etc/httpd/conf/httpd.keytab',
...                 ccache_file='/tmp/krb5cc_pid_appname'):
...     pass

If you have another Keytab that is be elsewhere and a credential cache for special purpose, you may pass the keytab_file and ccache_file.