Re: [PATCH v2] upload-pack: add tracing for fetches

[Jeff King <peff@peff.net>]

On Tue, Oct 17, 2023 at 09:12:47PM +0000, Robert Coup via GitGitGadget wrote:

> Information on how users are accessing hosted repositories can be
> helpful to server operators. For example, being able to broadly
> differentiate between fetches and initial clones; the use of shallow
> repository features; or partial clone filters.
> 
> a29263c (fetch-pack: add tracing for negotiation rounds, 2022-08-02)
> added some information on have counts to fetch-pack itself to help
> diagnose negotiation; but from a git-upload-pack (server) perspective,
> there's no means of accessing such information without using
> GIT_TRACE_PACKET to examine the protocol packets.
> 
> Improve this by emitting a Trace2 JSON event from upload-pack with
> summary information on the contents of a fetch request.
> 
> * haves, wants, and want-ref counts can help determine (broadly) between
>   fetches and clones, and the use of single-branch, etc.
> * shallow clone depth, tip counts, and deepening options.
> * any partial clone filter type.
> 
> Signed-off-by: Robert Coup <robert@coup.net.nz>
> ---
>     upload-pack: add tracing for fetches
>     
>     
>     Changes since V1
>     ================
>     
>      * Don't generate the JSON event unless Trace2 is active.
>      * Code style fix.

Thanks, the first bullet point there addressed my only concern.

The rest looks good to me overall. I think it is a useful feature to
have (as Taylor mentioned, GitHub has something similar via custom
code), but it has been long enough since I have operated a server that I
don't have opinions on what specific items should or should not be
included. :)

-Peff