circolog

A syslog daemon implementing circular buffer, in-memory storage.

This is useful when you want to keep some (heavy detailed) log available, but you don't want to log too many things to disk.

On your "main" syslog, send some message to this one!

Integration examples

In these examples I'll refer to the usage of UNIX sockets. They are more secure than TCP/UDP sockets because they have file permissions, they can be "masked" using mount namespaces, etc. However, circlogd supports udp/tcp sockets easily, so that should not be an issue.

syslog-ng

To integrate into syslog-ng, put this in /etc/syslog-ng/conf.d/circolog.conf

destination d_circolog {
        unix-dgram("/run/circolog-syslog.sock"
                   flags(syslog-protocol)
                  );
};
log { source(s_src); destination(d_circolog); };

and run circologd -syslogd-socket /run/circolog-syslog.sock -query-socket /run/circolog-query.sock

Client

curl might be enough of a client for most uses.

curl --unix-socket /run/circolog-query.sock localhost/

will give you everything that circologd has in memory

If you want to "follow" (as in tail -f) you need to use the websocket interface. However, I don't know of any websocket client supporting UNIX domain socket, so you have two options:

1. wait until I write a proper circolog-tail client implementing it all
2. Use circologd with -query-addr 127.0.0.1:9080, add some iptables rule to prevent non-root to access that port, and run ws ws://localhost:9080/ws. You'll get all the "backlog", and will follow new log messages.