Re: [BuildStream] Buildbox-casd logs

[Benjamin Schubert <contact benschubert me>]

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Wednesday, 11 September 2019 10:39, Jürg Billeter <j bitron ch> wrote:

> On Wed, 2019-09-11 at 08:04 +0100, Daniel Silverstone via buildstream-list wrote:
>
> > On Tue, Sep 10, 2019 at 17:12:18 +0000, Benjamin Schubert wrote:
> >
> > > I therefore would propose to save its output to
> > > 'XDG_CONFIG_HOME/buildstream/buildbox-casd.log'. We would always append to
> > > this file, and not erase it.
> >
> > This has the potential to become large and surprising to users. Given it
> > is not configuration nor valuable except in the case of diagnosis, I'd
> > argue that it more properly belongs in $XDG_CACHE_HOME/buildstream
> > somewhere.
>
> I agree, $XDG_CACHE_HOME is a better location.

Oups my bad, that's what I wanted to mean. We agree here

> > Also, I'd be tempted to rotate that log somehow, but I appreciate that
> > might be out of scope for bst itself.
>
> I almost suggested storing each session log as a separate file in CAS,
> relying on existing expiry, but that's not exactly helpful to debug CAS
> issues.
>
> Storing it as simple file probably makes sense, however, I'm also
> worried about the log growing without limits. If we're not supporting
> full log rotation, could we at least use a very simple approach to
> avoid unlimited log file growth? E.g., on startup check the current
> size of the log file and if it's above a certain threshold, delete or
> rename it (or cut off the oldest part).

Storing in CASD itself is indeed probably not acceptable.
What about a rotation? We keep the last 10 logs of CASD (last 10 sessions)
On startup, before we launch CASD, we rename each file buildbox-casd.log.X+1,
and remove any that is X>=10?

Would that address all the problems?