Open Stack

Thanks for the tips Stan.

 > it is stored exactly as it comes from Heat. In theory conversion to
 > string could happen on Heat side, but most likely it just the output 
 > of reporter made it look like this

Did some digging and it actually seems to be a string on heat's end. 
python-cinderclient seems to present volume attachment info as a list:

"""
from cinderclient.v2 import Client
...
for i in cinder.volumes.list():
   print(type(i.attachments))

<type 'list'>
"""

whereas printing the value of outputs from python-heatclient gives:

"""
from heatclient.client import Client
...
s = heat.stacks.get('murano--sjsbdj0xwhrkz2')
pp = pprint.PrettyPrinter(indent=4)
pp.pprint(s.outputs)

[   {   u'description': u'No description given',
         u'output_key': 
u'vol-08aea08f-f553-4f71-b839-bf4637516eaf-attachments',
         u'output_value': u"[{u'server_id': 
u'0f5731c1-da17-4209-a2ef-270c7056f9a3', u'attachment_id': u'88
1a5cea-be9e-4335-ad37-a24d09b36911', u'attached_at': 
u'2017-03-31T14:05:26.000000', u'host_name': None, u'
volume_id': u'6c97f825-32e9-4369-8580-a4a576e67612', u'device': 
u'/dev/vda', u'id': u'6c97f825-32e9-4369-8
580-a4a576e67612'}]"},
<snip>
         u'output_key': u'addresses--ae9a638e712d450a87492ed792025a97',
         u'output_value': [   {   u'OS-EXT-IPS-MAC:mac_addr': 
u'fa:16:3e:f6:26:ab',
                                  u'OS-EXT-IPS:type': u'fixed',
                                  u'addr': u'10.0.61.12',
                                  u'port': 
u'7967a4de-ccc1-49ec-a35c-f4d515e6cc96',
                                  u'version': 4}]},
<snip>
"""

(note the value for 'addresses--ae9a638e712d450a87492ed792025a97' is in 
the correct format)

Changing the schema type of this in heat from STRING to LIST fails to 
validate[0], so somewhere between cinder and heat this is not getting 
deserialised properly.

Anyhow, I think the issue has moved beyond the scope of MuranoPL, so I'm 
just sending this more as a follow up for anyone who happens to be reading.

Thanks again for pointing me in the right direction.

-Paul

[0] 
https://github.com/openstack/heat/blob/master/heat/engine/resources/openstack/cinder/volume.py#L222-L225


On 30/03/17 19:55, Stan Lagun wrote:
> Hi Paul,
>
>> Here both key and value appear to be a string (note, I can't confirm this as the typeinfo function doesn't appear to be available in Instance.yaml for some reason... perhaps I'm using it wrong)
>
> They are not strings. Reporter converts everything that is passed to it
> into string by doing unicode(obj). What you see is the Python string
> representation of lists and dicts, where every unicode string is
> prefixed with "u".
> Typinfo function works on objects (instances of MuranoPL classes), not
> on primitive types like strings, dicts and lists.
>
>> 1) Why is the content of this 'get_attr' coming from heat being stored in the stack outputs as a string,
> it is stored exactly as it comes from Heat. In theory conversion to
> string could happen on Heat side, but most likely it just the output of
> reporter made it look like this
>
>> 2) Is there a way I can cast this to a list of dicts or similar
> structure so it can be iterated as expected?
> It's hard to answer without seeing your code and how you got the results
> that you provided.
>
>>  when I access this from a sample app, I end up with a list of strings,
> shown by $reporter as: ...
>
> Curly braces in the output indicate that this is not a list of strings
> but rather the single dict converted to a string by reporter. So what
> you see is the value of
> that 'vol-7c8ee61f-a444-46a1-ad70-fc6fce6a7b56-attachments' output,
> which sounds like what you're wanted it to be. In MuranoPL you can have
> very detailed contracts: not just [] (any list) but something like
> Contract:
>   - key1: string().notNull()
>     key2: int().notNull()
>
> which is a list of dicts with contract on each dict entry. If you don't
> get contract violation exception, you can be sure that the list contains
> list of dicts with appropriate keys/values rather than list of strings
> or anything else
>
>
> Sincerely yours,
> Stan Lagun
> Principal Software Engineer @ Mirantis
>
> <mailto:slagun at mirantis.com>
>
> On Thu, Mar 30, 2017 at 10:17 AM, Paul Bourke <paul.bourke at oracle.com
> <mailto:paul.bourke at oracle.com>> wrote:
>
>     Hi Stan,
>
>     I had a quick(hopefully) question about MuranoPL that I hope you
>     might be able to help with, Felipe had mentioned you are very
>     knowledgeable in this area. If you don't have time please disregard!
>
>     I'm working on a patch for the Murano core library to make volume
>     attachment info available, which is available at
>     https://review.openstack.org/451909
>     <https://review.openstack.org/451909>. It's mostly working, but I'm
>     having some issues getting the types correct in MuranoPL to make
>     this info consumable by end users.
>
>     The attachment info from a sample run in the stack $outputs looks
>     like this (taken from the dashboard using $reporter)
>
>     u'vol-7c8ee61f-a444-46a1-ad70-fc6fce6a7b56-attachments':
>     u"[{u'server_id': u'2891067b-e7bb-4ab9-a759-9e81096c0682',
>     u'attachment_id': u'7456a4b0-3abd-48a0-a0cb-f3fa0f2706bb',
>     u'attached_at': u'2017-03-30T16:51:57.000000', u'host_name': None,
>     u'volume_id': u'373e4a5a-46b6-4091-82d6-b3dba62d552b', u'device':
>     u'/dev/vda', u'id': u'373e4a5a-46b6-4091-82d6-b3dba62d552b'}]"
>
>     Here both key and value appear to be a string (note, I can't confirm
>     this as the typeinfo function doesn't appear to be available in
>     Instance.yaml for some reason... perhaps I'm using it wrong)
>
>     My goal is to then set this into a property of CinderVolume.yaml,
>     with a Contract of '[]'. However, when I access this from a sample
>     app, I end up with a list of strings, shown by $reporter as:
>
>     (u"[{u'server_id': u'2891067b-e7bb-4ab9-a759-9e81096c0682',
>     u'attachment_id': u'f5bd50ab-4040-4e2b-8b50-790781d9bc37',
>     u'attached_at': u'2017-03-30T16:51:59.000000', u'host_name': None,
>     u'volume_id': u'ed7eb535-9e81-4c97-b063-86936d4ee306', u'device':
>     u'/dev/vdb', u'id': u'ed7eb535-9e81-4c97-b063-86936d4ee306'}]",)
>
>     So my question is:
>
>     1) Why is the content of this 'get_attr' coming from heat being
>     stored in the stack outputs as a string, and
>
>     2) Is there a way I can cast this to a list of dicts or similar
>     structure so it can be iterated as expected?
>
>     Any tips much appreciated.
>
>     Thanks,
>     -Paul
>
>