[stgt] Machine readable output for tgtadm --lld [driver] --op show --mode target

[Dr. Volker Jaenisch]

Hi Chris!

Thanks for your support.

Chris Webb schrieb:
> "Dr. Volker Jaenisch" <volker.jaenisch at inqbus.de> writes:
>
>   
>> We are coding a fencing daemon for the stgt target in python/zope3/grok.
>>     
>
> We use stgt as part of a infrastructure management system too, and would
> find more regular and parseable output invaluable. However, our system is
> written in shell and C, so JSON would be as bad for us as the current 'human
> readable' form: it's just not a very 'system-level' format choice.
>   
JSON you may easily use from within C (And some dozens of other languages).
Please have a look at http://json.org where you will find to 5 JSON 
libraries for C.

But I agree that  some other output views are needed. E.G. someone only 
likes to have the information
"What initiators are currently connectet to target foo". Then he should 
get a simple list of the initiators.

>> killer:/home/volker/workspace/tgt-0.9.6/usr# ./tgtadm --lld iscsi --op
>> show --mode target
>> {'1':
>>    {'class' : 'target'
>>      'name' : 'de.inqbus.storage:vmigration'
> How about just a straight list of
>
>   de.inqbus.storage:vmigration iscsi ready
>   [...]
>
> for --op show-brief --mode target, which is a small change given where
> you've stopped coding :-) and can be trivially parsed in any language
> including C and shell, so it'll be more widely useful to administrators.
>   
If you like to get the whole status picture as one big chunk there will 
have to be more than just a simple list since there are some 1:N 
relations which do not fit into one list.
For instance we need the ACL information as well as the intitiators over 
all targets at once.
This is only possible with a data structure that can handle hirachically 
organized data.
Beside XML which may be an overkill I know only JSON as a common and 
standard following and easily parseable exchange format.

This is the actual state of coding

{'1':
    {'name' : 'de.inqbus.storage:vmigration',
    'Driver' :'iscsi',
    'State' : 'ready',
    'nexus' : {
        '1': {
            'Initiator': iqn.1993-08.org.debian:01:d48cfa3cdf83,
            'Connection': 0,
            'ip' : '127.0.0.1'
            }
        }
    'luns' : {
        '0': {
            'Type': controller,
            'SCSI ID': 'IET     00010000',
            'SCSI SN': 'beaf10',
            'Size': '0 MB',
            'Online': 'Yes',
            'Removable media': 'No',
            'Backing store': 'No backing store'
        }
        '1': {
            'Type': disk,
            'SCSI ID': 'IET     00010001',
            'SCSI SN': 'beaf11',
            'Size': '250059 MB',
            'Online': 'Yes',
            'Removable media': 'No',
            'Backing store': '/dev/sda'
        }
    }               <<< here we are now
    Account information:
    ACL information:
        127.0.0.0/24



Best Regards,

Volker

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   Dr.  Volker Jaenisch      http://www.inqbus.de
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