Charm series in bundles (Was Re: Juju 2.0 and local charm deployment)

[Ian Booth]

If the charm store charm defines a series in the URL, then we will consider it
an error to specify a different series using the attribute. But charm store URLs
are not required to have a series, so we can use the attribute in that case. It
also allows users to easily switch between store and local charms during
development just by replacing "./" with "cs:"

     nova-compute:
       series: xenial
       charm: ./nova-compute

     nova-compute:
       series: xenial
       charm: cs:nova-compute


On 10/03/16 12:21, Rick Harding wrote:
> I'm not sure we want to make this attribute apply to charmstore charms.
> We've an established practice of the charmstore url being the series
> information. It gives the user a chance to have conflicting information if
> the charmstore url is cs:trusty/nova-compute and the series attribute is
> set to xenial. I think we should toss an error to a bundle that has series:
> specified for a charmstore based charm value (or non-local value whichever
> way you want to think about it)
> 
> On Wed, Mar 9, 2016 at 6:29 PM Ian Booth <ian.booth at canonical.com> wrote:
> 
>> One additional enhancement we need for bundles concerns specifying series
>> for
>> multi-series charms, in particular local charms now that the local repo
>> will be
>> going away.
>>
>> Consider:
>>
>> A new multi-series charm may have a URL which does not specify the series.
>> In
>> that case, the series used will be the default specified in the charm
>> metadata
>> or the latest LTS. But we want to allow people to choose their own series
>> also.
>>
>> So we need a new (optional) Series attribute in the bundle metadata.
>>
>> bundle.yaml
>>   series: trusty
>>   services:
>>     nova-compute:
>>       series: xenial <------ new
>>       charm: ./nova-compute
>>       num_units: 2
>>
>> or with a charm store charm
>>
>> bundle.yaml
>>   series: trusty
>>   services:
>>     nova-compute:
>>       series: xenial    <------ new
>>       charm: cs:nova-compute
>>       num_units: 2
>>
>>
>> Note: the global series in the bundle still applies if series is not
>> otherwise
>> known.
>> The new series attribute is per charm.
>>
>> So in the case above, cs:nova-compute may ordinarily be deployed on trusty
>> (the
>> default series in that charm's metadata). But the bundle requires the
>> xenial
>> version. With the charm store URL, we can currently use
>> cs:xenial/nova-compute
>> but that's not the case for local charms deployed out of a directory. We
>> need a
>> way to allow the series to be specified in that latter case.
>>
>> We'll look to make the changes in core initially and can followup later
>> with the
>> GUI etc. The attribute is optional and only really affects bundles with
>> local
>> charms.
>>
>>
>>
>> On 09/03/16 09:53, Ian Booth wrote:
>>> So to clarify what we'll do. We'll support the same syntax in bundle
>> files as we
>>> do for deploy.
>>>
>>> Deploys charm store charms:
>>>
>>> $ juju deploy cs:wordpress
>>> $ juju deploy wordpress
>>>
>>> Deploys a local charm from a directory:
>>>
>>> $ juju deploy ./charms/wordpress
>>> $ juju deploy ./wordpress
>>>
>>> So below deploys a local nova-compute charm in a directory co-located
>> with the
>>> bundle.yaml file.
>>>
>>>  series: trusty
>>>  services:
>>>    nova-compute:
>>>      charm: ./nova-compute
>>>      num_units: 2
>>>
>>> This one deploys a charm store charm:
>>>
>>>  series: trusty
>>>  services:
>>>    nova-compute:
>>>    charm: nova-compute
>>>    num_units: 2
>>>
>>>
>>>
>>> On 09/03/16 03:59, Rick Harding wrote:
>>>> Long term we want to have a pattern when the bundle is a directory with
>>>> local charms in a directory next to the bundles.yaml file. We could not
>> do
>>>> this cleanly before the multi-series charms that are just getting out
>> the
>>>> door. I think that bundles with local charms will be suboptimal until we
>>>> can get those bits to line up.
>>>>
>>>> I don't think we want to be doing the file based urls, but to build a
>>>> pattern that's reusable and makes sense across systems. Creating a
>> standard
>>>> pattern I think is the best path forward.
>>>>
>>>> On Tue, Mar 8, 2016 at 12:26 PM Martin Packman <
>> martin.packman at canonical.com>
>>>> wrote:
>>>>
>>>>> On 05/03/2016, Ian Booth <ian.booth at canonical.com> wrote:
>>>>>>>
>>>>>>> How will bundles work which reference local charms? Will this work as
>>>>>>> expected where nova-compute is a directory at the same level as a
>> bundle
>>>>>>> file?
>>>>>>>
>>>>>>> ```
>>>>>>> series: trusty
>>>>>>> services:
>>>>>>>   nova-compute:
>>>>>>>     charm: ./nova-compute
>>>>>>>     num_units: 2
>>>>>>> ```
>>>>>>>
>>>>>>
>>>>>> The above will work but not until a tweak is made to bundle
>> deployment to
>>>>>> interpret a path on disk rather than a url. It's a small change. This
>>>>> would
>>>>>> be done as part of the work to remove the local repo support.
>>>>>
>>>>> Can we keep interpreting the the reference in the bundle as a url, but
>>>>> start supporting file urls? That seems neater than treating the cs:
>>>>> prefix as magic not-a-filename.
>>>>>
>>>>> The catch is that there's no sane way of referencing locations outside
>>>>> a base url.
>>>>>
>>>>>     charm: file:nova-compute
>>>>>
>>>>> Works as a reference to a dir inside the base location, but:
>>>>>
>>>>>     charm: file:../nova-compute
>>>>>
>>>>> Will not work as a reference to a sibling directory. And absolute file
>>>>> paths are pretty useless across machines.
>>>>>
>>>>> Martin
>>>>>
>>>>> --
>>>>> Juju-dev mailing list
>>>>> Juju-dev at lists.ubuntu.com
>>>>> Modify settings or unsubscribe at:
>>>>> https://lists.ubuntu.com/mailman/listinfo/juju-dev
>>>>>
>>>>
>>>>
>>>>
>>
>