[chef] Re: Re: idempotent lwrp behaviour

[Peter Wilcsinszky < >]

Hi Greg!

I'm trying to make things a bit more clear: The package resource does exactly what it needs to do, I have problems with the download resource right before it. The download resource uses remote_file to download a file to a temporary location to make that file (.deb) available for my package resource. No matter if the package resource is not updated because the package was already installed, if the download resource downloads the file again it will fire notifications and my outer services will be restarted needlessly.

Thanks for the pointer, but I was already aware of that stuff (the updated? method is deprecated now). I was just saying, that you can do updated_by_last_action(true) because this value will not be changed if the resource does not change, but you cannot set it to false, because if the resource changes it will definitely update it to true. And if I'm right this method should not have an option to set it to false (at least not a public one) because it is confusing.

My current problem is, that I have to use my handrolled method to get the package state before declaring my resources. Should I try to get this information by loading the current resource at first?

On Wed, Sep 10, 2014 at 1:26 AM, Greg Zapp < " target="_blank"> > wrote:

Hi Pepov,

I'll be honest that I'm having a hard time determining exactly where you're issue is based on what's posted but.. The package resource should not be "updated_by_last_action" if the package is already installed and up to date.  This slide deck has a slide on "Nested Resources" that might be applicable to what you are doing(and if not def worth knowing) http://www.slideshare.net/geekbri/lwrp-presentation .  It involves running the nested resources in a new context and then checking that context to see if resources have been updated or not.  It's a bit gross IMHO, and there may be a better way of doing it, but it's fairly straight forward.

I hope that helps and apologise if it does not :)

-Greg

On Wed, Sep 10, 2014 at 12:31 AM, Peter Wilcsinszky < " target="_blank"> > wrote:

Hi all!

I've run into a problem, when I was trying to implement an lwrp, that does something like the artifact_package resource in https://github.com/RiotGames/artifact-cookbook

The simplified base of the lwrp looks like:

use_inline_resources

action :install

    custom_artifact_download_lwrp ...

    package ...

end

I wanted to test its idempotency, to make sure no notification will be propagated when the package is already installed. If any of the inner resources inside the custom_artifact_download_lwrp resource was modified (the file has been removed from the cache - we want to do periodic cleanup there) the notification was sent out even if the package was already installed. I wanted to force "mute" it somehow, because I want to avoid restarting services needlessly. I've naively tried:

c = custom_artifact_download_lwrp

c.updated_by_last_action(false)

But after digging into the code I've realised I can not do this, since this code runs before the resource collection is converged. So if a resource gets modified the updated flag will be true and I cannot do anything about it. Is there a way to do this?

Anyways, after reading the lwrp docs more closely, I've realized that I should do a conditional before declaring any of my resources, so ended up in doing this:

def skip_install?(name, version)

status = `dpkg -s #{name}`

status.lines.any? { |l| /^Status: install ok installed/.match l } &&

status.lines.any? { |l| /^Version: #{version}$/.match l }

end

action :install

    unless skip_install?()

        custom_artifact_download_lwrp ...

        package ...

    end

end

I'm wondering if there is a more appropriate way of checking package availability, and wheter I've ended up doing this right or missing something?

Thanks,

pepov