Varnish version 6.0.9 [[ https://github.com/varnishcache/varnish-cache/blob/6.0/doc/changes.rst#varnish-cache-609-2021-11-24 | is out ]]. The new version includes the following changes:
- Increase the default stack size to 64k. (3617)
- Correctly reset the received SIGHUP flag in libvarnishapi when no handling function for this signal is registered. (3437)
- Make it possible to set the sess.timeout_idle VCL variable also when using VCL syntax version 4.0. (3564)
- New varnishstat counter MAIN.esi_req. This increments for each ESI subrequest that is made.
- The CLI command vcl.show -v now outputs the builtin VCL source last, after any included VCL sources files.
- Improve the ability of log utilities to detect log overruns. (3716)
- Add an option to configure to use libunwind for the stack backtrace in the panic output. (3717)
- A bug in vmod_blob for base64 decoding with a length argument and non-padding decoding has been fixed (3378)
- The socket option inheritance checks now correctly identifies situations where UDS and TCP listening sockets behave differently, and are no longer subject to the order the inheritance checks happens to be executed (3732).
- IPv6 listen endpoint address strings are now printed using brackets.
Among the changes, [[https://github.com/varnishcache/varnish-cache/pull/3717 | libunwind support for back-traces ]] seems particularly interesting. It requires some minor packaging change. I think just adding libunwind to `Build-Depends` should be sufficient for the build system to autmoatically use it or at worst we'll have to pass `--with-unwind` to `configure`.