[Added Sanjiva to the list]

Hi All,

IMO this composite application model is really important for the future of
Stratos and it will become the foundation for all other features. Therefore
we need to make sure that it is simple, easy to understand, covers all
currently available requirements and easy to extend. At some point we might
need to add extensions to support well known similar specifications such as
CAMP, CloudML and TOSCA.

At present I do not see much feedback from the community on this. Shall we
walk through this and suggest refinements? I had some concerns and added
them to the below document [1]. @IsuruH: Is the document up to date?

[1]
https://docs.google.com/a/wso2.com/document/d/1qnArxF8obhbjMLUbPAENQMn94fPSd3AVqO41mxhnJXE/edit#

Thanks


On Thu, Jul 3, 2014 at 12:22 PM, Isuru Haththotuwa <isu...@apache.org>
wrote:

> For the initial implementation for persisting Service Group Definitions,
> the functionality will cover:
>
> 1. Nested Service Groups
> 2. Validation of the availability of referred Service Groups and Cartridges
>
> I have copy-pasted two sample Service Group definitions [1, 2] below.  [2]
> is a nested group.
> [1].
> {
>     "name": "group1",
>     "cartridges": [
>         "mysql", "mongoDB"
>     ],
>     "dependencies": {
>         "killBehaviour": "kill-none"
>     }
> }
>
> [2].
> {
>     "name": "group2",
>     "subGroups": [
>         "group1"
>     ],
>     "cartridges": [
>         "php"
>     ],
>     "dependencies": {
>         "startupOrder": [
>             {
>                 "start": "group.group1",
>                 "after": "cartridge.php"
>             }
>          ],
>         "killBehaviour": "kill-dependents"
>
>     }
> }
>
>
>
>
> On Mon, Jun 2, 2014 at 10:52 AM, Isuru Haththotuwa <isu...@apache.org>
> wrote:
>
>> Hi Devs,
>>
>> This is an addition to the discussion happened in the thread [1]. I have
>> included a very basic sequence diagram to show the flow of how Service
>> Grouping would happen for the initial implementation.
>>
>> ​
>>  composite_app_1.png
>> <https://docs.google.com/a/wso2.com/file/d/0B4pCC9A49FwCRDhqQ0JDRl9tQjA/edit?usp=drive_web>
>> ​
>> Short description of the flow:.
>>
>> 1, 2 & 3. Deploy Components' Definitions that would be included in the
>> top level Composite Application. Typically, a component would map to a
>> single cartridge. For sample JSON definitions of a component, please refer
>> [1].
>>
>> 4. Deploy a Group Definition, which would logically group the relevant
>> components. This would include information on the Startup Order of each
>> component, and how to handle the termination/error situations as well (Kill
>> Behavior).
>>
>> 5. Deploy a Nested Group Definition, which would contain one/more of
>> Components and Groups.
>>
>> 6. Deploy the Composite Application Definition. This would map to the
>> operation 'Subscription' which we have currently, when spinning up a single
>> cartridge instance. As per the discussion that took place in the above
>> mentioned thread, this was decided to be called the 'Composite
>> Application Definition' deployment, rather than a Subscription.
>>
>> For the initial version, we can restrict this Composite Application
>> Definition only to contain information for each group/component, such as
>> aliases, git repositories and relevant info as required, etc., and not
>> allow further grouping at this level.
>>
>> A typical basic Composite Application Definition, in JSON format, would
>> be as follows:
>>
>> {
>>   "name": "group2",
>>   "alias": "<group2_alias>",
>>   "components": [
>>     {
>>       "name": "component2",
>>       "alias": "<component2_alias>",
>>       "repoUrRL": "<repo_url>"
>>     }
>>   ],
>>   "groups": [
>>     {
>>       "name": "group1",
>>       "alias": "group1_alias",
>>       "components": [
>>         {
>>           "name": "component1",
>>           "alias": "<component1_alias>",
>>           "xxx": "<xxx>"
>>         },
>>         {
>>           "name": "component3",
>>           "alias": "<component3_alias>",
>>           "yyy": "<yyy>"
>>         }
>>       ]
>>     }
>>   ]
>> }
>>
>> More information is available in the above mentioned mail thread and in
>> [2]. Please share your feedback on this.
>>
>>
>> [1]. [Discuss] Grouping of services (cartridges)
>> [2].
>> https://docs.google.com/a/wso2.com/document/d/1qnArxF8obhbjMLUbPAENQMn94fPSd3AVqO41mxhnJXE/edit#
>>
>
>


-- 
Imesh Gunaratne

Technical Lead, WSO2
Committer & PPMC Member, Apache Stratos

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