[chef] Re: Re: Lock vs. Snapshot

[Jos Backus < >]

On 9/17/15, 4:20 PM, "Daniel DeLeo" 
<
 
 on behalf of 

 >
 wrote:



>On Thursday, September 17, 2015 at 4:01 PM, Jos Backus wrote:
>> Hi,
>>  
>> https://github.com/chef/chef-dk/blob/master/POLICYFILE_README.md talks ;
>> about ‘lock’, but would ‘snapshot’ not be a better name? After all, it 
>> looks like a snapshot of cookbooks and their metadata (although granted 
>> the _effect_ is to lock machines in the policy group to those cookbooks). 
>> Maybe I misunderstand?  
>>  
>> Jos  
>“lock” and “lockfile" are the terms I’d expect people to be familiar with, 
>as they're used by bundler and berkshelf and probably other tools as well.
>
>To me the term “lock” feels more natural since you generally have 
>dependencies that are floating to some degree (for example, if you specify a 
>dependency in your metadata like “~> 2.0”) and you’re locking that to a 
>specific version. Likewise, “snapshot” feels more like a “freeze frame” of a 
>thing that’s changing naturally, like a nightly build of a project or 
>something. I’m probably heavily biased by the way these terms are used 
>elsewhere, but I suspect most users will have similar experiences with these 
>terms.

While I understand what you are saying, I’d argue that what it is and what it 
does are separate things. It is a snapshot with the effect of locking things 
down (because the ‘chef install/update’ resolves the cookbook versions and 
ultimately picks a single version of each cookbook, which together I’d call a 
snapshot of the state of the cookbook universe). So in that sense you could 
indeed call it a lock based on the effect that it has. But when I look at it, 
I can’t help but see a snapshot. :-)

At any rate, as you and Lamont point out, the consistency gained with other 
software is of course valuable.

Thanks for taking the time to explain, Daniel.

Jos


>
>--  
>Daniel DeLeo
>
>
>