pyControl Log and Exception

Hubertus: A nice trick is to pass the 'tracefile' keyword argument when you build the object. For example:

 

 

import sys

 

import pycontrol.pyControl as pc

 

b = pc.BIGIP(hostname = '192.168.1.245', username = 'admin', password = 'admin', wsdl_files = ['System.Statistics'], tracefile = sys.stdout)

 

 

....which will produce a dump of requests/responses to stdout so you can see what is going on (I'm using the iPython shell here):

 

 

In [4]: b.System_Statistics.get_version()

 

_________________________________ Fri Jun 06 08:18:08 2008 REQUEST:

 

xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" SO

 

AP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"> ader> on>

 

_________________________________ Fri Jun 06 08:18:09 2008 RESPONSE:

 

200

 

OK

 

-------

 

Date: Fri, 06 Jun 2008 12:18:08 GMT

 

Server: Apache

 

Set-Cookie: BIGIPAuthCookie=DD94709528BB1C83D08F3088D4043F4742891F4F; path=/;

 

SOAPServer: EasySoap++/0.6

 

Transfer-Encoding: chunked

 

Content-Type: text/xml; charset="UTF-8"

 

 

xmlns:E="http://schemas.xmlsoap.org/soap/envelope/"

 

xmlns:A="http://schemas.xmlsoap.org/soap/encoding/"

 

xmlns:s="http://www.w3.org/2001/XMLSchema-instance"

 

xmlns:y="http://www.w3.org/2001/XMLSchema"

 

xmlns:iControl="urn:iControl"

 

E:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">

 

 

xmlns:m="urn:iControl:System/Statistics">

 

s:type="y:string">BIG-IP_v9.4.2

 

 

 

 

 

Out[4]: {'return': 'BIG-IP_v9.4.2'}

 

 

You can also specify a specific log file to dump to if you wish - this isn't limited to sys.stdout (although it's probably the most useful thing for debugging). From time to time you'll get the odd error, which I've forced as an example:

 

 

Let's find a getter that wants a specific argument structure, and intentionally pass in a bad value. A handy trick is to print out the special attribute "_h" for the getter method. This will tell you what the input and output params are:

 

 

In [8]: print b.System_Statistics.get_virtual_compression_statistics._h

 

 

InParams Count: 1

 

device_names: Common.StringSequence

 

OutParams Count: 1

 

return: System.Statistics.VirtualCompressionStatistics

 

 

So the get_virtual_compression_statistics() method expects an argument of device_names. Passing in a plain old string to this should generate a type mismatch (any parameter that ends in a plural, such as 'device_names' expects a list at a minimum):

 

 

In [10]: b.System_Statistics.get_virtual_compression_statistics(device_names = 'hello')

 

 

_________________________________ Fri Jun 06 08:22:57 2008 RESPONSE:

 

500

 

Internal Server Error

 

-------

 

Date: Fri, 06 Jun 2008 12:22:57 GMT

 

Server: Apache

 

Set-Cookie: BIGIPAuthCookie=DD94709528BB1C83D08F3088D4043F4742891F4F; path=/;

 

SOAPServer: EasySoap++/0.6

 

Connection: close

 

Transfer-Encoding: chunked

 

Content-Type: text/xml; charset="UTF-8"

 

 

xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"

 

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

 

xmlns:xsd="http://www.w3.org/2001/XMLSchema">

 

 

 

xsi:type="xsd:string">SOAP-ENV:Server

 

xsi:type="xsd:string">Exception caught in System::Statistics::get_virtual_compression_s

 

tatistics()

 

Exception: Common::NotImplemented

 

 

 

 

 

 

EvaluateException: Type mismatch (http://www.w3.org/2001/XMLSchema namespace) (got string wanted QName)

 

[Element trace: /SOAP-ENV:Envelope/SOAP-ENV:Body/SOAP-ENV:Fault/faultcode]

 

 

When you see the "got string wanted QName" error, it almost always means you've generated a 500 ISE and that you've not passed in the correct structure - I know this error well!

 

 

Anyhow, handling these exceptions with a try: is probably the best way, since about all you'll get is the QName error which is fairly useless but conforms to the spec according to the ZSI folks...

 

 

I hope this is useful. At some point I'll try and do a write-up on debugging and give examples of some of the common data structures that get passed into various calls.

 

 

-Matt

If you want to get the appropriate exceptions from the box, instead of the "generic" QNAME error, you can have that with a small change in the ZSI library.

 

 

In the ZSI folder (in the site-packages directory, or inside the appropriate .egg file), just edit the fault.py file, and look for the FaultType.typecode definition. Within it, where it reads "QName(pname='faultcode')", change it to "String(pname='faultcode')". Save it and you should be able to get the expected "FaultException" instead of the dreaded EvaluateException.