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Ed_Summers's avatar
Ed_Summers
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Jan 19, 2017

F5 Python SDK: How to get virtual server availability?

Due to my limited Python and SDK experience I am finding it difficult to easily obtain the availability state of a virtual server. Given a 'virtual' object, what is the best/easiest way to return the...
devops
iControlREST
LTM
python
sdk
stats
Hannes_Rapp's avatar
Hannes_Rapp
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Jan 19, 2017

Great to see more people opting to use the SDK!

You can work with the output normally, as with any dict-type, using 

dict.get('something')
. Add in a set of square-brackets, if the extracted value is yet another key-value pair, and if you're looking for a very specific match: 
dict.get('something')['something']
.

Note: In the for-loop, I'm using 

virtual.name
- this extraction works without use of 
.get('name')
because 'name' is a 1st-level extraction - no nesting is involved. For the same reason, I can do 
state = stats.entries...
in my function, instead of 
state = stats.get('entries')...

f5-sdk v2.2.0 ; py3.4.3 ; 11.5.4

from f5.bigip import ManagementRoot

def get_vs_state(vs_name):
    virtual_s = API_ROOT.tm.ltm.virtuals.virtual.load(name=vs_name)
    stats = virtual_s.stats.load()
    state = stats.entries.get('status.availabilityState')['description']
    return state

API_ROOT = ManagementRoot("bip-01", "admin", "admin")
VIRTUALS = API_ROOT.tm.ltm.virtuals.get_collection()

 EXAMPLE OF USE:
 Print AvailabilityState of all Virtual Servers
for virtual in VIRTUALS:
    print("Name: '%s' AvailabilityState: '%s'" % (virtual.name, get_vs_state(virtual.name)))
  • Ed_Summers's avatar
    Ed_Summers
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    Jan 19, 2017

    Thank you for your help and patience! Much appreciated...

    Not sure if there is a difference in the data structures between our versions: F5 SDK v2.0.2 BIGIP 12.1.1 Python 3.3.2

    When I run the stats.entries.get method you outlined above, I get a return of 'None'. However there is a value for status.availibilityState buried in nested dicts for stats.entries.

    Here's a test I ran in interactive shell (I have a module that obtains a token and base object of 'mgmt'):

    >>> virtuals = mgmt.tm.ltm.virtuals.virtual.load(name='my_virtual_name')
>>> stats = virtuals.stats.load()
>>> state = stats.entries.get('status.availabilityState')['description']
Traceback (most recent call last):
  File "", line 1, in 
TypeError: 'NoneType' object is not subscriptable
>>> stats.entries
{'https://localhost/mgmt/tm/ltm/virtual/my_virtual_name/~Common~my_virtual_name/stats': {'nestedStats': {'selfLink': 'https://localhost/mgmt/tm/ltm/virtual/my_virtual_name/~Common~my_virtual_name/stats?ver=12.1.1', 'kind': 'tm:ltm:virtual:virtualstats', 'entries': {'totRequests': {'value': 0}, 'status.statusReason': {'description': 'The virtual server is available'}, 'csMinConnDur': {'value': 0}, 'fiveMinAvgUsageRatio': {'value': 0}, 'syncookie.syncookies': {'value': 0}, 'csMeanConnDur': {'value': 0}, 'tmName': {'description': '/Common/my_virtual_name'}, 'clientside.slowKilled': {'value': 0}, 'syncookie.hwSyncookies': {'value': 0}, 'ephemeral.bitsOut': {'value': 0}, 'syncookie.rejects': {'value': 0}, 'ephemeral.curConns': {'value': 0}, 'clientside.pktsOut': {'value': 0}, 'syncookie.syncacheCurr': {'value': 0}, 'clientside.bitsIn': {'value': 0}, 'ephemeral.pktsOut': {'value': 0}, 'destination': {'description': '192.168.1.1:443'}, 'syncookieStatus': {'description': 'not-activated'}, 'syncookie.hwsyncookieInstance': {'value': 0}, 'syncookie.swsyncookieInstance': {'value': 0}, 'clientside.evictedConns': {'value': 0}, 'clientside.curConns': {'value': 0}, 'clientside.totConns': {'value': 0}, 'clientside.bitsOut': {'value': 0}, 'oneMinAvgUsageRatio': {'value': 0}, 'ephemeral.totConns': {'value': 0}, 'syncookie.accepts': {'value': 0}, 'status.availabilityState': {'description': 'available'}, 'syncookie.syncacheOver': {'value': 0}, 'syncookie.hwAccepts': {'value': 0}, 'ephemeral.bitsIn': {'value': 0}, 'status.enabledState': {'description': 'enabled'}, 'ephemeral.evictedConns': {'value': 0}, 'fiveSecAvgUsageRatio': {'value': 0}, 'clientside.maxConns': {'value': 0}, 'csMaxConnDur': {'value': 0}, 'ephemeral.pktsIn': {'value': 0}, 'ephemeral.slowKilled': {'value': 0}, 'clientside.pktsIn': {'value': 0}, 'ephemeral.maxConns': {'value': 0}, 'cmpEnabled': {'description': 'enabled'}, 'cmpEnableMode': {'description': 'all-cpus'}}}}}

    I'm not sure if your version is the same, but it appears the stats are nested three levels deep, first key being a link, second 'nestedStats', then 'entries'. If I follow the entire path I do get the value:

    >>> print(stats.entries.get('https://localhost/mgmt/tm/ltm/virtual/my_virtual_name/~Common~my_virtual_name/stats')['nestedStats']['entries']['status.availabilityState']['description'])
    available

    Am I running something incorrectly or are the returned structures different between our versions? I can run through the nest like you mentioned and get the value, though the first key (formatted as a URL) throws me off as I'm not sure if there is an elegant way to reference it. I could get it by listing the keys for that level of dict but that seems kludge-y.

  • Hannes_Rapp's avatar
    Hannes_Rapp
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    Jan 19, 2017

    Code was tested on BigIP 11.5.4. Will update answer for 12.1.1 in 15 min.

     

  • Hannes_Rapp's avatar
    Hannes_Rapp
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    Jan 19, 2017

    You're right. The response structure of virtual stats is different in 12.1.1, and it's absolutely dreadful. Best I could offer now is a hack so that this insignificant part at the beginning would be cut out 

    {'https://localhost/mgmt/tm/ltm/virtual/my_virtual_name/~Common~my_virtual_name/stats': {'nestedStats': {
    , then everything will work exactly the same as in my 11.5.4 sample, but it's kind of a dirty approach.

    Will look further into cleaner solutions tomorrow.

  • Ed_Summers's avatar
    Ed_Summers
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    Jan 19, 2017

    Thanks! I feel better if only because it wasn't me being totally dim. :)

     

    Everything other than the first key is static so I can look past those. The first key is dynamic...I can do an ugly hack for it. I don't like it but it will work for now.

     

    Thanks so much for your time and testing! If you do happen across anything elegant I'm all ears!

     

  • Hannes_Rapp's avatar
    Hannes_Rapp
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    Jan 20, 2017

    For Jason's reference:

    entries =

    {'https://localhost/mgmt/tm/ltm/virtual/my_virtual_name/~Common~my_virtual_name/stats': {'nestedStats': {'selfLink': 'https://localhost/mgmt/tm/ltm/virtual/my_virtual_name/~Common~my_virtual_name/stats?ver=12.1.1', 'kind': 'tm:ltm:virtual:virtualstats', 'entries': {'totRequests': {'value': 0}, 'status.statusReason': {'description': 'The virtual server is available'}, 'csMinConnDur': {'value': 0}, 'fiveMinAvgUsageRatio': {'value': 0}, 'syncookie.syncookies': {'value': 0}, 'csMeanConnDur': {'value': 0}, 'tmName': {'description': '/Common/my_virtual_name'}, 'clientside.slowKilled': {'value': 0}, 'syncookie.hwSyncookies': {'value': 0}, 'ephemeral.bitsOut': {'value': 0}, 'syncookie.rejects': {'value': 0}, 'ephemeral.curConns': {'value': 0}, 'clientside.pktsOut': {'value': 0}, 'syncookie.syncacheCurr': {'value': 0}, 'clientside.bitsIn': {'value': 0}, 'ephemeral.pktsOut': {'value': 0}, 'destination': {'description': '192.168.1.1:443'}, 'syncookieStatus': {'description': 'not-activated'}, 'syncookie.hwsyncookieInstance': {'value': 0}, 'syncookie.swsyncookieInstance': {'value': 0}, 'clientside.evictedConns': {'value': 0}, 'clientside.curConns': {'value': 0}, 'clientside.totConns': {'value': 0}, 'clientside.bitsOut': {'value': 0}, 'oneMinAvgUsageRatio': {'value': 0}, 'ephemeral.totConns': {'value': 0}, 'syncookie.accepts': {'value': 0}, 'status.availabilityState': {'description': 'available'}, 'syncookie.syncacheOver': {'value': 0}, 'syncookie.hwAccepts': {'value': 0}, 'ephemeral.bitsIn': {'value': 0}, 'status.enabledState': {'description': 'enabled'}, 'ephemeral.evictedConns': {'value': 0}, 'fiveSecAvgUsageRatio': {'value': 0}, 'clientside.maxConns': {'value': 0}, 'csMaxConnDur': {'value': 0}, 'ephemeral.pktsIn': {'value': 0}, 'ephemeral.slowKilled': {'value': 0}, 'clientside.pktsIn': {'value': 0}, 'ephemeral.maxConns': {'value': 0}, 'cmpEnabled': {'description': 'enabled'}, 'cmpEnableMode': {'description': 'all-cpus'}}}}}

    Challenge:

    Please extract ['status.availabilityState']['description'] from the entries dictionary in an elegant/re-usable way. You may also instead modify the request input to come up with a less-bulky output (if there's a better way)