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From Alex Heneveld <alex.henev...@cloudsoftcorp.com>
Subject Re: Parameterize the start effector
Date Tue, 05 Jan 2016 14:39:27 GMT

yavor-

i like the direction this is going.  thinking aloud however would it be 
better to recommend that install and customize are non-destructive by 
default, with an option for destruction?  that way it does the right 
thing on first launch, and on relaunch, with a way to force it to 
clear.  (for install this is already the case by default; for customize 
it is not but we could advise that best practice is for it to be so.)

and then on start we'd add optional parameters "install.forceClean" and 
"customize.forceClean" which would delete INSTALL_DIR and RUN_DIR .

does that stack up?

--a


On 05/01/2016 14:13, Yavor Yanchev wrote:
> Hi,
>
> I just want to follow up on the previous mail with some more information.
>
> In Brooklyn, most of the entities expose start, stop and restart 
> effectors. Brooklyn docs have a detailed explanation of the current 
> start/stop/restart effectors behavior [1].
> Many users want to start a process/service that has been stopped by 
> them using the stop() effector. Naturally, they are trying to use the 
> start() effector to launch the process, but not the restart() effector 
> as it is outlined in the documentation [1]. Having start() effector 
> executed it goes through the install+customize+launch phases which can 
> be confusing for some of the users. Most of them will expect just the 
> launch phase to be execute without install+customize. It can be rather 
> problematic for some entities such as databases [1].
>
> It will be very helpful to provide our users with a way so they can 
> skip install and customize phases and just launch stopped process via 
> the start() effector.
>
> My intention is to extend the SoftwareProcess' start() effector with a 
> new boolean parameter "skipInstallation" with "false" as its default 
> value.
>
> It can be created as a static class (StartSoftwareParameters) in the 
> SoftwareProcess interface. Such parameter class is currently missing 
> and start parameters are defined via the Startable interface as part 
> of the start effector's body.
> The proposed addition of the new parameter will require a change in 
> the AbstractSoftwareProcessDriver as well. 
> AbstractSoftwareProcessDriver's start() already uses a config with a 
> similar name and meaning (install.skip).
> *install.skip* can omit the install phase, but not the customize. We 
> can slightly change its behavior to skip the customize phase and/or 
> introduce an additional config which controls omitting of the 
> customize phase.
>
> WDYT?
>
> Regards,
> Yavor
>
> [1] 
> https://brooklyn.apache.org/v/latest/concepts/stop-start-restart-behaviour.html
>
> On 01/04/2016 01:11 PM, Yavor Yanchev wrote:
>> Hi All,
>>
>> Happy New Year!
>>
>> Brooklyn uses want to be able to parameterize the start effector so 
>> it behaves like the restart effector when a special parameter is set.
>>
>> What do you think about introducing a new boolean parameter called 
>> "skipInstallation" so the start effector can skip the install and 
>> customize steps and just launch the process?
>>
>> Some time ago, Aled provided a good explanation why we might need 
>> such functionally in a comment regarding PR #792 [1].
>>
>> Regards,
>> Yavor
>>
>> [1] 
>> https://github.com/apache/incubator-brooklyn/pull/792#issuecomment-131797684 
>>
>>
>
>


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