Added before_save to MiqTask to initialize MiqTask#started_on when task become active

[yrudman]

Before:
MiqTask#started_on was not set if state attribute updated directly (like task.update_attributes(:state => MiqTask::STATE_ACTIVE))
related BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1536126

After:
Added before_save callback to initialize #started_on when state set to "Active"

@miq-bot add-label core, technical debt

\cc @gtanzillo @jameswnl

[agrare]

@yrudman so this will set started_on to be essentially equal to created_on which isn't very useful.
Could the UI show created_on like it used to and we can work on setting a useful started_on when the first queue item in the task is delivered (future release)?

[Fryguy]

Perhaps ensure_started as a method name? started is an adjective, and a verb reads nicer.

[Fryguy]

LGTM... Just change the method name.

[yrudman]

@agrare created_on populated when record created,
started_on would be populated only when task become active (delivered by queue worker and recipient will update state attribute to "Active").

We do show data previously displayed in Started column, only column re-named to Queued

[agrare]

@yrudman 👍 I missed the if state == STATE_ACTIVE part and thought you were setting started_on on first save

[yrudman]

@miq-bot add-label gaprindashvili/yes

[miq-bot]

Checked commits yrudman/manageiq@a56d3b7~...0c8969b with ruby 2.3.3, rubocop 0.52.0, haml-lint 0.20.0, and yamllint 1.10.0
2 files checked, 0 offenses detected
Everything looks fine. 👍

[yrudman]

@Fryguy method name changed, ready for merge

[simaishi]

Gaprindashvili backport details:

$ git log -1
commit 4e25d98d2fcc0a6222ee484b401d846010a1b6e3
Author: Jason Frey <[email protected]>
Date:   Mon Jan 22 16:08:40 2018 -0500

    Merge pull request #16863 from yrudman/added-before-safe-to-miq-task-to-initialize-strted_on
    
    Added before_save to MiqTask to initialize MiqTask#started_on when task become active
    (cherry picked from commit d992f980a857db789c8aa8b3636bf1b6559ca539)