Forum Discussion
Twirrim_94896
Nimbostratus
Nimbostratusstruggling to create irules
I'm using python 2.6.6 and pycontrol 2.0.1 to connect to our load balancer and configure it. I'm trying to make a rough start at creating a standard provisioning script for any new subdomains that are set up. I like python/pycontrol in general it's proving fairly easy and simple to get things rolling (particularly in comparison to the usual PITA that seems to go with Perl & APIs), I'm able to pull all sorts of data from the LBs with ease.
I'm going to keep hacking away at this and will update if I manage to solve this in case it's useful to others. The examples I've been able to find so far don't seem to show python creating irules.
!/usr/bin/python
Import pycontrol and connect to loadbalancer
import pycontrol.pycontrol as pc
myLTM = pc.BIGIP(
hostname = 'serv.er.addre.ss',
username = 'admin',
password = 'password',
fromurl=True,
wsdls = ['LocalLB.Rule'])
Provide rl as a shortcut to the rules service
rl=myLTM.LocalLB.Rule
Query the user for the domain
appname = raw_input("Enter new application/subdomain name:")
Generate the content of the new iRule
irules_content = []
irules_content.append(u' Rule generated for %s' % appname)
irules_content.append(u'when HTTP_REQUEST {')
irules_content.append(u' Check if Host header is %s.ourdomain.com' % appname)
irules_content.append(u' if {[HTTP::host] eq "%s.ourdomain.com"}{' % appname)
irules_content.append(u' use %s pool' % appname)
irules_content.append(u' pool %s_pool' % appname)
irules_content.append(u' }')
irules_content.append(u'}')
Combine it all into a single \n separated string
irules_content = '\n'.join(irules_content)
Define the name for the iRule
irule_name = appname+"_redirect"
Print to screen
print irule_name
print irules_content
Attempt to create rule
rl.create(rule_name = irule_name, rules = irules_content)
Double check for sanity
double_check = rl.query_rule(rule_names = [irules_name])
print "\nCreated iRule:\n"
print double_check[0].rule_definitionWhilst rl.create appears to work, no exception is reported, double_check fails telling me the requested rule wasn't found. I don't see any way to commit changes to the interface. I'm sure it's the "rules = " bit that is wrong, if I use rule_definition that I'd expect to use there, it fails telling me rules wasn't there:
"WebFault: Server raised fault: 'Could not find element by name: rules'"
edit: Really not keen on this forum software.. just doesn't want to accept code tags around the code, seems to expect me to prepend [ code ] to every line?! (minus the spaces)
Twirrim_94896Bah.. after struggling with this for a good while today, inspiration struck just after posting this..
Need to define a dictionary (dict) object and pass that to the iRule create command:
Attempt to create rule irule_def = dict(rule_name=irule_name,rule_definition = irules_content) rl.create(rules=[irule_def])
L4L7_53191Nicely done. If you've not gone through it up until now, you may want to go through the typefactory screencast that I did a while back to help get folks up to speed on how pycontrol/suds handles types. You've discovered, as have a couple of other folks, that Suds will take a normal python data structure and try to do the right thing with it. IIRC, this isn't completely consistent though, especially with nested types. So I always use the typefactory, which is much more explicit...
Anyhow, here's an example that may be useful for you (done via an iPython interactive shell session). It may save you a few lines of code.
Thanks for the post and I look forward to hearing more about your project!In [18]: r.create.params Out[18]: [(rules, u'LocalLB.Rule.RuleDefinitionSequence')] This is the data structure we need to pass into the create call. Let's create the LocalLB.RuleDefinition object... In [19]: r_def = r.typefactory.create('LocalLB.Rule.RuleDefinition') In [20]: print r_def (LocalLB.Rule.RuleDefinition){ rule_name = None rule_definition = None } This shows us what attributes we need to tickle to pass in the call. Let's do that now... In [21]: r_def.rule_name = 'YOYO_pyControl' The name of the rule. Now we'll actually add the iRule code. In [22]: raw_code = ''' ....: when HTTP_REQUEST { ....: log local0. "Python - I can fly!!" ....: }''' Now we'll add this to our object's rule_definition attribute... In [23]: r_def.rule_definition = raw_code Now we'll add it to BigIP... In [24]: r.create(rules = [r_def]) Notice to create a 'sequence' I just treat it like a list. Let's see if it saved! In [25]: r.get_list() Out[25]: [ _sys_APM_activesync, _sys_auth_ssl_cc_ldap, _sys_auth_krbdelegate, _sys_https_redirect, YOYO_pyControl, _sys_auth_ssl_crldp, _sys_auth_ssl_ocsp, nextgen-test, connection-limit, nextgen-dg-acl]
-Matt Cauthorn