Does there exist an open-source distributed logging library?

Question

I'm talking about a library that would allow me to log events from different machines and would align these events on a "global" time axis with sufficiently high precision.

Actually, I'm asking because I've written such a thing myself in the course of a cluster computing project, I found it terrifically useful, and I was surprised that I couldn't find any analogues.

Therefore, the point is whether something like this exists (and I better contribute to it) or nothing exists (and I better write an open-source analogue of my solution).

Here are the features that I'd expect from such a library:

• Independence on the clock offset between different machines
• Timing precision on the order of at least milliseconds, preferably microseconds
• Scalability to thousands of concurrent logging processes, with at least several megabytes of aggregated logs per second
• Soft real-time operation (t.i. I don't want to collect 200 big logs from 200 machines and then compute clock offsets and merge them - I want to see what happens "live", perhaps with a small lag like 10s)

Answer 1

You could use log4j/log4net targeting a central syslog daemon. log4j has a builtin SyslogAppender, and in log4net you can do it as shown here. log4cpp docs here.

There are Windows implementations of Syslog around if you don't have a Unix system to hand for this.

Answer 2

Facebook's contribution in the matter is called 'Scribe'.

Excerpt:

Scribe is a server for aggregating streaming log data. It is designed to scale to a very large number of nodes and be robust to network and node failures. There is a scribe server running on every node in the system, configured to aggregate messages and send them to a central scribe server (or servers) in larger groups.

...

Scribe is implemented as a thrift service using the non-blocking C++ server. The installation at facebook runs on thousands of machines and reliably delivers tens of billions of messages a day.

The API is Thrift-based, so you have a good platform coverage, but in case you're looking for simple integration for Java you may want to have a look at Digg's log4j appender for Scribe.