[chef] Re: Re: Question - only if your configuration files are changed

[Mike < >]

If you're interested in the internals, here's the code (for Chef 11,
although I don't think it changed significantly  since Chef 10).

https://github.com/opscode/chef/blob/master/lib/chef/provider/template.rb#L51-L76
https://github.com/opscode/chef/blob/master/lib/chef/provider/file.rb#L275-L302

The 'template' provider inherits the 'file' provider and uses the
'backup' method from 'file'.

-M

On Thu, Feb 7, 2013 at 9:19 AM, Spike Grobstein
<
 >
 wrote:
> Interesting.
>
> So how do the internals of this work? Does chef generate a new output file 
> in a temp folder, compare the new file to the old file, then if they 
> differ, update and notify?
>
> I was always under the impression that this would notify every single time, 
> so I was incredibly apprehensive about doing this on our postgres and redis 
> production servers.
>
> Thanks for the info. You've seriously just simplified my life.
>
>
>
> ...spike
>
> On Feb 7, 2013, at 9:06 AM, Mike wrote:
>
>> +1 to Thom.
>>
>> Spike - Since Chef keeps some backups around of previous version in
>> /var/cache/chef typically (you can also see the filename in a chef run
>> with debug where something changes), there's no need to timestamp your
>> file.
>> Also, leveraging filesytem mtime to see when a file was changed is useful.
>>
>> If you were statically entering a date/time of an Operator change -
>> say, add "2013-02-07 Mike added a new gadget" to your file as a
>> changelog, that might be useful, but also might be more effort than
>> it's worth - that stuff typically lives in our source control history
>> anyways.
>>
>> -M
>>
>> On Thu, Feb 7, 2013 at 9:03 AM, Thom May 
>> <
 >
>>  wrote:
>>> note that if you put a timestamp in the template, you'll get a 
>>> notification
>>> every time, since chef will update the timestamp every time it runs.
>>>
>>>
>>> On Thu, Feb 7, 2013 at 1:33 PM, Spike Grobstein 
>>> <
 >
>>> wrote:
>>>>
>>>> I've often wondered this myself. I currently keep one backup of the 
>>>> config
>>>> and restart only if the current and the backup differ, but its incredibly
>>>> hacky and doesn't work if you put a "configured by chef" time stamp at 
>>>> the
>>>> top.
>>>>
>>>> It doesn't appear that that recipe only restarts if the file is changed.
>>>> Or am I missing something?
>>>>
>>>>
>>>>
>>>> ...spike
>>>> (Sent via handheld, please pardon spelling errors)
>>>>
>>>> On Feb 7, 2013, at 8:18 AM, Mike 
>>>> <
 >
>>>>  wrote:
>>>>
>>>>> See here, from the opsocde ntp cookbook:
>>>>>
>>>>> https://github.com/opscode-cookbooks/ntp/blob/master/recipes/default.rb#L44-L50
>>>>>
>>>>> On Thu, Feb 7, 2013 at 6:50 AM, Alex Vitola 
>>>>> <
 >
>>>>> wrote:
>>>>>> How do I restarting a service only if your configuration files are
>>>>>> changed
>>>>>>
>>>>>>
>>>>>> Example: ntp service
>>>
>>>
>