[systemd-devel] Looking for experiences formalizing an API for journal messages

[Lennart Poettering]

On Wed, 29.07.15 15:02, Anne Mulhern (amulhern at redhat.com) wrote:

> > systemd of courses uses its on its own, and we tried to document
> > the fields we use in systemd.journal-fields(7), though it might be
> > slightly incomplete.
> > 
> > But yes, this is indeed API, and deserves complete documentation, like
> > any C API, any D-Bus API or a any REST API would need too.
> > 
> > Lennart
> > 
> > --
> > Lennart Poettering, Red Hat
> > 
> 
> What I'm wondering about is the existence of some processes (not systemd), that have an
> agreement on a set of key-value pairs that they communicate with
> through the journal.

There are multiple bindings for the journal logging API on github for
various languages. It might be worth searching for users of these
APIs, as well as our C API.

libvirt talks the journal logging protocol natively btw, it might be a
codebase to check for this.

> It seems like, even though there is a mechanism for adding additional key/value pairs,
> regular expression matching is still kind of the norm.

Well, yes, regexp searching is definitely more popular. But do note
that the journal will implicitly append a big number of structured
fields, such as user, process, MAC, unit information, so each record
will have a good number of metadata fields already without clients
sending the metadata themselves. 

Lennart

-- 
Lennart Poettering, Red Hat