The latest release of Varnish Cache (6.1.0) is now available on Section, bringing about several new features and stability improvements, albeit minor in the words of Poul-Henning Kamp.
Section made this version of Varnish Cache available within our platform 2hrs after the source code release, further highlighting the speed and flexibility of the Section Edge Platform.
Notable Varnish Cache 6.1.0 Updates
- Since new users often forget to vcl.discard their old VCLs, they have added a warning when you have more than 100 VCLs loaded. There are parameters to set the threshold and decide what happens when it is exceeded (ignore/warn/error).
req.http.Hostis now mandatory and requests are handled without it on the fast DoS avoidance path.
req.gracehad been previously removed, but has been reintroduced, since there are use cases that cannot be solved without it. Similarly,
req.ttlused to be deprecated and is now fully supported again.
- The evaluation of the
beresp.keeptimer has changed a bit. keep sets a lifetime in the cache in addition to TTL for objects that can be validated by a 304 “Not Modified” response from the backend to a conditional request (with If-None-Match or If-Modified-Since). If an expired object is also out of grace time, then
vcl_hitwill no longer be called, so it is impossible to deliver the “keep” object in this case.
beresp.filtersvariable is readable and writable in
vcl_backend_response. This is a space-separated list of modules called VFPs, for “Varnish fetch processors”, that may be applied to a backend response body as it is being fetched.
obj.hitshas been fixed to return the correct value in
vcl_hit(it had been 0 in
Hostheader in client requests is mandatory for HTTP/1.1, as proscribed by the HTTP standard. If it is missing, then
builtin.vclcauses a synthetic 400 “Bad request” response to be returned.
Next Scheduled Varnish Cache Release
According to Poul-Henning, the next Varnish Cache release will take place March 15th 2019, and later this year they will decide whether that version will become 6.2 or 7.0.
If you need assistance upgrading to Varnish Cache 6.1 in your Section account, we’re here to help. Get in touch