[jira] [Commented] (BROOKLYN-322) On rebind, entity temporarily (incorrectly) reports serviceUp=false

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/BROOKLYN-322?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15405916#comment-15405916 ] 

ASF GitHub Bot commented on BROOKLYN-322:
-----------------------------------------

GitHub user aledsage opened a pull request:

    https://github.com/apache/brooklyn-server/pull/286

    BROOKLYN-322: feeds don’t poll if entity unmanaged

    Fixes https://issues.apache.org/jira/browse/BROOKLYN-322. See the description in that jira issue.

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/aledsage/brooklyn-server brooklyn-322

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/brooklyn-server/pull/286.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #286
    
----
commit 952f017b36f86017dd42aa99f0c9f91ea6443e21
Author: Aled Sage <al...@gmail.com>
Date:   2016-08-03T13:26:06Z

    code tidy: SoftwareProcess tests

commit ac155de48e4871e3f33f15881576c2526c11705c
Author: Aled Sage <al...@gmail.com>
Date:   2016-08-03T13:26:38Z

    BROOKLYN-322: feeds don’t poll if entity unmanaged

----


> On rebind, entity temporarily (incorrectly) reports serviceUp=false
> -------------------------------------------------------------------
>
>                 Key: BROOKLYN-322
>                 URL: https://issues.apache.org/jira/browse/BROOKLYN-322
>             Project: Brooklyn
>          Issue Type: Bug
>            Reporter: Aled Sage
>
> With Brooklyn 0.10.0-SNAPSHOT (but also with older versions, I presume)...
> When rebinding to many entities, some software processes temporarily show serviceUp=false before going back to showing the correct serviceUp=true.
> The problem is with the polling of their feeds. It starts polling immediately, rather than waiting for the entity to be managed. This can cause some feeds to throw an exception (e.g. when {{SoftwareProcessImpl.connectServiceUpIsRunning}} calls {{driver.isRunning()}}, and that tries to execute an ssh command). The exception causes the feed to set it to whatever value the {{onException}} tells it to use.
> It is more likely to happen when there are many entities, because the entities will be unmanaged for longer.
> The solution is to not poll when the entity is not managed.
> This is a simple fix in ((Poller}}.
> It might cause problems for those trying to use a Poller to poll just once: it might skip that single poll because the entity is unmanaged. I think we can ignore that. I don't know of any use-cases doing that. Also, I suspect that it might be a good thing! On rebind we don't necessarily want to do that single poll again, and when the feed is first registered we'd hope that it is done when the entity is managed (if done in {{SoftwareProcess.connectSensors()}}, but not if done in the entity's init method).
> We could revisit this in the future, so that if the entity is unmanaged (but e think it will soon be managed), then we reschedule it for when the entity is actually managed.



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