[chef] Re: Re: How to access attributes later in a recipe from where they're set

[Edward Sargisson < >]

Hi Bryan and Vladimir,
I didn't include the contents of the aws_ebs_volume resource as I'm
fairly sure they're not relevant. As Vladimir said, the effect of tha
aws_ebs_volume resource is that the volume id gets saved into
node[:aws][:ebs_volume][:app_db_volume][:volume_id].

Vladimir's idea of setting an default attribute didn't work. The
receip compiled and ran but the resulting file had no value for the
volume_id.
I looked at the ruby_block resource but I can't see that helping
because I need to poke the attribute into a template resource.
What did work was using the attribute directly in the recipe. This
isn't ideal because I wanted to use that template in a number of
places with different volume ids <sigh>.

Thanks a lot for the help.
Cheers,
Edward

On Thu, May 19, 2011 at 11:48 AM, Vladimir Girnet
<
 >
 wrote:
> I run into similar issue some time ago, but I could manage it by defining
> require attribute at role level.
>
> It looks like attribute
> "node[:aws][:ebs_volume][:app_db_volume][:volume_id]" is set/created only
> after resource "aws_ebs_volume" is executed first time.
> But at compile time Chef wants to assign to "volume_id" this attribute,
> which is undefined yet.
>
> I think you may try to define a generic value for this attribute at the
> beginning of the recipe, but I'm not sure that "volume_id" will be
> re-evaluated at aws resource execution.
>
> A better way may be to call attribute directly in template file. Template
> resource will run after aws resource, which will ensure attribute is already
> defined.
>
> Hope this helps.
>
>
> On 5/19/2011 3:48 PM, Edward Sargisson wrote:
>>
>> Hi all,
>> I'm a bit confused about when Ruby gets compiled, how this interacts
>> with attributes and how to get attribute data that is saved early in
>> the recipe to be available later in the recipe.
>>
>> My desired outcome is to have the recipe create a volume from a
>> snapshot, grab the resulting volume id and insert it into the backup
>> script so that new backups can snapshot the new volume.
>>
>> Early in my recipe I have this:
>> aws_ebs_volume "app_db_volume" do
>>   <useful content>
>> end
>>
>> The aws_ebs_volume resource saves the resulting EBS volume id to node
>> data.
>>
>> Later on I have - this is where I grab the volume id that was saved
>> and put it into the snapshot:
>> template "/usr/local/sbin/app_db_snapshot.sh" do
>>   source "snapshot.sh.erb"
>>   mode 0744
>>   owner "root"
>>   group "root"
>>   variables({
>>     :directory =>  "/var/lib/postgresql/8.4/main",
>>     :description =>  "Apps Database QA",
>>     :volume_id =>  node[:aws][:ebs_volume][:app_db_volume][:volume_id]
>>   })
>> end
>>
>> I had this running fine in a node that had already successfully
>> attached to the volume and saved the volume id.. When I ran it on a
>> brand new node I get:
>> FATAL: NoMethodError: undefined method `[]' for nil:NilClass
>> This happens just as soon as the processing gets to the recipe but
>> before it does anything at all.
>>
>> My hyptothesis is that the recipe is being compiled by Ruby and it's
>> not finding the node data and thus the error.
>>
>> So, how do I access node data from earlier in the recipe? Or do I need
>> to break this code into a separate recipe?
>>
>> Thanks in advance,
>> Edward
>
>