Fwd: [charms.reactive] http relation.available gets called on upgrade-charm hook, gives error.

2015-10-27 Thread Merlijn Sebrechts 
Hi Cory


Thanks for the explanation. Is there a way to override the scope of the
http relation without forking the interface?



Kind regards
Merlijn

2015-10-26 18:21 GMT+01:00 Cory Johns :

> Merlijn,
>
> You'll note that the docs for auto_accessors
> 
> says that it's not a good idea to use with non-GLOBAL scoped relations, for
> this very reason.  The problem is that there's no way which unit's or
> service's host and port you are trying to get, since there could be many.
> If it's true that there should only be a single connected service on this
> relation, then you should switch it to  GLOBAL scope to indicate that.
> Otherwise, you need to be handling the possibility of multiple connected
> units explicitly.
>
> See
> https://github.com/johnsca/juju-relation-mysql/blob/master/provides.py#L74
> for an example of how an interface layer should handle multiple
> conversations.
>
> On Mon, Oct 26, 2015 at 5:58 AM, Merlijn Sebrechts <
> merlijn.sebrec...@gmail.com> wrote:
>
>> Hi all
>>
>>
>> I have the following piece of code that reacts to the
>> httprelation.available hook (called rest2jfed in this case):
>>
>>
>> @when('rest2jfed.available')
>> def setup_rest2jfed(rest2jfed):
>> hostname = rest2jfed.host()
>> port = rest2jfed.port()
>> # Do some stuff with hostname and port
>> hookenv.status_set('active', 'Ready')
>>
>>
>> This piece of code gets called on the upgrade-charm hook. This throws an
>> error because there is not a relationship context.
>>
>>   File "lib/charms/reactive/relations.py", line 88, in __accessor
>> return self.get_remote(field)
>>   File "lib/charms/reactive/relations.py", line 308, in get_remote
>> return self.conversation(scope).get_remote(key, default)
>>   File "lib/charms/reactive/relations.py", line 255, in conversation
>> raise ValueError('Unable to determine default scope: no current hook
>> or global scope')
>>
>> Am I using this relation wrong or is this a bug?
>>
>>
>>
>> Kind regards
>> Merlijn
>>
>> --
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>>
>>
>
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Re: [charms.reactive] http relation.available gets called on upgrade-charm hook, gives error.

2015-10-27 Thread Cory Johns 
Merlijn,

Unfortunately, the correct solution for the issue with the HTTP interface
layer is to change how the requires side works a bit.  I went ahead and
made those changes and moved the repo (with Ben's permission) to
https://github.com/juju-solutions/interface-http (which will also allow
easier PR submissions).  I added a README with example usage but it will
require a bit of change to your code.  I also updated
interfaces.juju.solutions so that the next time you do a `charm build`, you
should get the new version of the interface.

Let me know if you run into any issues with that implementation, and of
course PRs are welcome.

As an aside, I just wanted to note that the http interface protocol is a
good example of one that has suffered for the lack of a standard
implementation like what the interface layer gives us.  When trying to
determine how to implement that side of the relation, it became apparent
that each charm that supports it seems to have added its own extensions to
the protocol (e.g., haproxy accepts entire HA proxy YAML configuration
blocks, Apache2 supports overriding the service grouping, etc.).  I only
implemented the most basic, common use-case as I saw it; if we, as a
community, determine that it needs to support more, we can do so, but
things like the HA proxy config block should really be in a separate
interface protocol (which could be a superset, with a negotiation protocol).

On Tue, Oct 27, 2015 at 5:04 AM, Merlijn Sebrechts <
merlijn.sebrec...@gmail.com> wrote:

> Hi Cory
>
>
> Thanks for the explanation. Is there a way to override the scope of the
> http relation without forking the interface?
>
>
>
> Kind regards
> Merlijn
>
> 2015-10-26 18:21 GMT+01:00 Cory Johns :
>
>> Merlijn,
>>
>> You'll note that the docs for auto_accessors
>> 
>> says that it's not a good idea to use with non-GLOBAL scoped relations, for
>> this very reason.  The problem is that there's no way which unit's or
>> service's host and port you are trying to get, since there could be many.
>> If it's true that there should only be a single connected service on this
>> relation, then you should switch it to  GLOBAL scope to indicate that.
>> Otherwise, you need to be handling the possibility of multiple connected
>> units explicitly.
>>
>> See
>> https://github.com/johnsca/juju-relation-mysql/blob/master/provides.py#L74
>> for an example of how an interface layer should handle multiple
>> conversations.
>>
>> On Mon, Oct 26, 2015 at 5:58 AM, Merlijn Sebrechts <
>> merlijn.sebrec...@gmail.com> wrote:
>>
>>> Hi all
>>>
>>>
>>> I have the following piece of code that reacts to the
>>> httprelation.available hook (called rest2jfed in this case):
>>>
>>>
>>> @when('rest2jfed.available')
>>> def setup_rest2jfed(rest2jfed):
>>> hostname = rest2jfed.host()
>>> port = rest2jfed.port()
>>> # Do some stuff with hostname and port
>>> hookenv.status_set('active', 'Ready')
>>>
>>>
>>> This piece of code gets called on the upgrade-charm hook. This throws an
>>> error because there is not a relationship context.
>>>
>>>   File "lib/charms/reactive/relations.py", line 88, in __accessor
>>> return self.get_remote(field)
>>>   File "lib/charms/reactive/relations.py", line 308, in get_remote
>>> return self.conversation(scope).get_remote(key, default)
>>>   File "lib/charms/reactive/relations.py", line 255, in conversation
>>> raise ValueError('Unable to determine default scope: no current hook
>>> or global scope')
>>>
>>> Am I using this relation wrong or is this a bug?
>>>
>>>
>>>
>>> Kind regards
>>> Merlijn
>>>
>>> --
>>> Juju mailing list
>>> Juju@lists.ubuntu.com
>>> Modify settings or unsubscribe at:
>>> https://lists.ubuntu.com/mailman/listinfo/juju
>>>
>>>
>>
>
>
> --
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>
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[charms.reactive] http relation.available gets called on upgrade-charm hook, gives error.

2015-10-26 Thread Merlijn Sebrechts 
Hi all


I have the following piece of code that reacts to the
httprelation.available hook (called rest2jfed in this case):


@when('rest2jfed.available')
def setup_rest2jfed(rest2jfed):
hostname = rest2jfed.host()
port = rest2jfed.port()
# Do some stuff with hostname and port
hookenv.status_set('active', 'Ready')


This piece of code gets called on the upgrade-charm hook. This throws an
error because there is not a relationship context.

  File "lib/charms/reactive/relations.py", line 88, in __accessor
return self.get_remote(field)
  File "lib/charms/reactive/relations.py", line 308, in get_remote
return self.conversation(scope).get_remote(key, default)
  File "lib/charms/reactive/relations.py", line 255, in conversation
raise ValueError('Unable to determine default scope: no current hook or
global scope')

Am I using this relation wrong or is this a bug?



Kind regards
Merlijn
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