[systemd-devel] remote journal enhancements

[Zbigniew Jędrzejewski-Szmek]

On Wed, Dec 18, 2013 at 08:44:36AM +0100, Holger Winkelmann [TP] wrote:
> Hi all,
> 
> we are following the discussion initiated by Cecil about systemd
> journal for a while. The last couple of weeks we have developed
> a Erlang adapter for the journal to allow structured native logging.
> Therefore we have developed a ejournald [1] backend for the Erlang
> logging framework lager [2]. ejournald also got a Erlang wrapper
> to query the journal for log entries and emit messages for new
> arriving messages.
> 
> By writing distributed applications we will look further for log
> aggregation in the style of the systems-journal-gateway.
> Regarding this I would like to know about the idea and plans of
> the systemd community. Following the emails about logger optimization
> Lennart mentioned something about kdbus transports for logging (on
> kdbus systems) further systemd has usually dubs APIs for introspection
> but the journal is access directly by journalctl and the corresponding
> C-API.
Yes, that's not going to change. Kdbus might be used for *sending* messages,
because it makes sends metadata about the sender and removes the need
for the (very slow and racy) querying of process attributes through
/proc. OTOH *reading* is going to stay independent of journald. In
some cases that would be even impossible, e.g. when journald is
running within a container, and we are looking at the logs from
outside.

> Are there any plans/ideas to give the journald a D-Bus/kdbus API for querying
> the journal? Or should reading/querying the journal totally decoupled
> from journald in a daemon like systems-journal-gateway?
> 
> If we work on a separate journal-gateway do you have any ideas/requirement
> about the API this should expose, again like D-Bus for local communication
> and i.e. HTTP, JSON-RPC, AMQP etc. for remote communication? Should we
> include any access control which honors the underlying journal fils ACLs
> or should we have ACLs for given fields on the journal?

Not directly related, but I intend to dig out my send-messages-over-http [1]
patches and adapt them to sd-event and resend during the christmas break.

Zbyszek

[1] http://lists.freedesktop.org/archives/systemd-devel/2012-November/007427.html