[Pkg-postgresql-public] Bug#891687: postgresql-common: dsfwew

[Christoph Berg]

Re: Daniel Kahn Gillmor 2018-02-28 <151977883437.31585.3826803256327598913.reportbug at alice.fifthhorseman.net>
> In particular, a user .service named "exampled" which keeps its
> state in `~/.config/example`.  An `exampled.service` unit might be
> configured with:
> 
>     Requires=pgcluster at example.service
>     After=pgcluster at example.service
> 
> So that if the user service is ever started, the cluster will be
> created on demand (in `~/.config/example/data`) and the "example"
> database will be ready for use (via unix-domain sockets in
> `$XDG_RUNTIME_DIR/example/`) before the user service is started.

Hi Daniel,

this is very interesting, especially Type=notify. I haven't yet had
time to look closely at the patches - my first question would be if we
could integrate the idea more tightly with the existing postgresql@
services which are already capable of launching clusters for different
users (though currently hardcoded to /etc/postgresql/*). The cluster
machinery itself (pg_ctlcluster and friends) can operate on different
roots if PG_CLUSTER_CONF_ROOT is set. Maybe that can be incorporated
to work better together.

One thing I have been thinking about was to replace pg_ctlcluster with
something more systemd-specific, including Type=notify operation. This
looks about what you have here.

Christoph