haproxy/dev/haring/README

This needs to be built from the top makefile, for example :

  make dev/haring/haring
DEV: haring: add a simple utility to read file-backed rings With the ability to back a memory ring into an mmapped file, it makes sense to be able to dump these files. That's what this utility does. The entire ring is dumped to stdout. It's well suited to large dumps, it converts roughly 6 GB of logs per second. The utility is really meant for developers at the moment. It might evolve into a more general tool but at the moment it's still possible that it might need to be run under gdb to process certain crash dumps. Also at the moment it must not be used on a ring being actively written to or it will dump garbage. The code is made so that we can envision later to attach to a live ring and dump live contents, but this requires that the utility is built with the exact same options (threads etc), and that the file is opened read-write. For now these parts have been commented out, waiting for a reasonably balanced and non-intrusive solution to be found (e.g. signals must be intercepted so that the tool cannot leave the ring with a watcher present). If it is detected that the memory layout of the ring struct differs, a warning is emitted. At the end, if an error occurs, a warning is printed as well (this does happen when the process is not cleanly stopped, but it indicates the end was reached). 2022-08-12 05:23:59 -04:00			`This needs to be built from the top makefile, for example :`

			`make dev/haring/haring`