Re: Plans for a library for btrfs?

[Goffredo Baroncelli <kreijack@inwind.it>]

On 2015-05-29 16:31, Roman Mamedov wrote:
> On Wed, 27 May 2015 14:31:28 +0200
> Stef Bon <stefbon@gmail.com> wrote:
> 
>> This program, which I've called fuse-backup, creates backup subvolumes
>> and snapshots by calling an extrenal script, which does something
>> like:
>>
>> btrfs subvolume snapshot -r %PathToBackup%/ %PathToSnapshot%
>>
>> This works perfect, but are there any plans to do this with a library?
> 
> If this works perfect, then what is the rationale for needing a library?

The problem in calling another executable, is that is very difficult to parse the program output.
For "btrfs sub snap" it is easy; but what about "btrfs fi df" or "btrfs fi show" ?

> Do you see a clear reason aside from any vague "it's supposed to be that way".
> In the Unix land it is perfectly normal for programs to call other
> self-contained programs to do their self-contained jobs:

Right, but now btrfs is a collection of tools; I don't think that it could e considered a "self-contained programs"... Other programs (eg systemd, udev) rewrite some code in order to avoid to call an external executable. This leads to code duplication with all the associated problems...

> http://www.catb.org/esr/writings/taoup/html/ch01s06.html#id2877684
> Not everything must to be a library linked into your main executable, some
> separation and calling external programs to do stuff such as mkfs or snapshot
> management seems perfectly fine and even better from the debug-ability
> standpoint.





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