Update to rrdc_create_r2

[alexwennerberg]

I put together some changes on https://github.com/alexwennerberg/rrd -- one of them is update to rrdc_create_r2

I've never worked with go's C bindings before, so I may have some issues. But before I try to clean them up and make a PR, I was thinking about the truncate parameter. With rrdc_create_r2's "no overwrite" parameter, I think it makes truncate obsolete. But this would be a breaking change. Do you think it's worth removing the truncate parameter in favor of no overwrite?

[ziutek]

I'm unsure about the truncate parameter. I can't see it in the code. Do you mean the Create(overwrite bool) method?

[alexwennerberg]

yes, sorry, that is what I meant! Here's the specific line:
https://github.com/alexwennerberg/rrd/blob/master/rrd.go#L109

my branch isn't quite ready to merge in, but I wonder what you think we should do with that parameter? deprecate it and do a version bump, maybe?

[ziutek]

I think Create should stay as it is (maybe rewritten to use the native RRD functionality), with your deprecation comment. It should be annotated that its overwrite parameter has precedence over what was set by the SetNoOverwite method. In my opinion such small change (adding support for one parameter) doesn't justify breaking compatibility.

Another Create-like method say (Create0, Create1, CreateDB, etc.) may be pointed in the deprecation comment as the right way to do things.

[alexwennerberg]

that makes sense. I think i’ll have some time this afternoon to put together a PR