Yeah, I kinda thought that it would be difficult to implement idempotency.
I’m not sure the build_if_missing would work, because of resource ordering. If I understand you correctly, you are suggesting something like this:
docker_image "myimage do
action :build_if_missing
end
remote_directory “/tmp/mydockercontext” do
notifies :build, “docker_image[myimage]”
end
But with this order, the docker image would be built before the context is set up.
Reversing the order of the resources would break the notification, because you cannot notify resources that come later in the recipe. Or am I mistaken about that?
Kevin Keane
The NetTech
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-----Original message-----
From: Sean OMeara someara@chef.io
Sent: Tuesday 1st September 2015 1:09
To: chef@lists.opscode.com
Subject: [chef] Re: docker cookbook and idempotency
Hi Kevin
Unfortunately, :build will perform work on every chef-client run. There isn’t really a way to “check” to see if the image contents are out of date given the inputs.
I’d have your build context notify a docker_image with the :build_if_missing action set.
-s
On Tue, Sep 1, 2015 at 12:21 AM, Kevin Keane Subscription <subscription@kkeane.com mailto:subscription@kkeane.com > wrote:
I love the docker cookbook - thanks to those who created and maintain it!
That said, there are a few things I’m trying to understand better. Specifically, how does idempotency work with the docker_image :build action? Does this rebuild the image on every chef run, or only when the build context has changed?
Currently, I am using a notification to rebuild the image when the build context has changed. But this is unsatisfactory because when the context is already up to date but the image is outdated or missing, it will not trigger a rebuild.
How do I solve this?
Kevin Keane
The NetTech
http://www.4nettech.com http://www.4nettech.com
Our values: Privacy, Liberty, Justice