Set limits for VM and Template names and descriptions

[masayag]

RHV enforce the following limits:

• VM name to 255 characters
• VM description to 255 characters
• Template name to 40 characters (it will be extended to 255 in ovirt-engine-4.2)
• Template description to 255 characters

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1529052

The UI enforces the limits on insertion for the name and description fields:

[masayag]

@miq-bot assign @gmcculloug

[masayag]

@miq-bot add_labels gaprindashvili/yes, bug

[gmcculloug]

What is the timeframe for the ovirt-engine-4.2 changes? Should we just use the higher value now? Are we going to remember to increase it once it is updated?

[Fryguy]

Do these changes apply to all supported versions of RHV?

[masayag]

@gmcculloug ovirt-engine-4.2 is already available upstream. However, if we increase the limit, the 'publish vm as template' might fail for ovirt-engine-4.1 (if the user will set a name longer than 40 chars).

That's why I thought to set the shorter limit of 4.1 which will work for both versions.

@Fryguy the limits which are specified in this PR are supported by all ovirt-engine versions (they were defined in the early days of ovirt-engine-3.x), except of the template name limit that was recently increased (in 4.2).

[gmcculloug]

@masayag I'm always a little concerned about enforcing these types of limits in the provisioning dialogs as admins can make modifications to the name value from automate. Like adding enumeration to the name value, but I do realized we need to start somewhere.

Two thoughts:

1. If you want to enforce this limit based on the provider level of the targeted environment you could create an validation method in the backend. For example: https://github.com/ManageIQ/manageiq/blob/master/app/models/miq_provision_virt_workflow/dialog_field_validation.rb. Users would still be able to disable this by modifying the dialog if they wanted/needed to.
2. This bug is internally reported and I would probably opt for using the larger template length value. If a user needed to smaller limit they could reduce the value in the dialog.

[masayag]

@gmcculloug I'd prefer the second option. I've updated the PR accordingly.

[miq-bot]

Checked commit masayag@1f2a123 with ruby 2.3.3, rubocop 0.47.1, haml-lint 0.20.0, and yamllint 1.10.0
0 files checked, 0 offenses detected
Everything looks fine. ⭐

[simaishi]

Gaprindashvili backport details:

$ git log -1
commit 0ae390bc3049e2121a125b8b48dc49eb659a514f
Author: Greg McCullough <[email protected]>
Date:   Thu Jan 4 09:40:55 2018 -0500

    Merge pull request #16736 from masayag/vm_template_limits
    
    Set limits for VM and Template names and descriptions
    (cherry picked from commit bf689eba47174db57344d593e53bb3cf28677c95)
    
    Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1531292