Log backend name/ip

[Cédric Jeanneret]

Hello,

I have a specific varnishncsa format, and I'm wanting to log the backend
used, especially when the request hits some director (either round_robin
or hash).

I think there would be two places in the VCL in order to log this
information:
* in vcl_backend_response
* in vcl_backend_error

Is this correct? If so, I seem to be unable to get the backend using, in
both cases, beresp.backend.ip

Here's how I do my stuff:

sub vcl_backend_response {
 std.log("backend_used:" + beresp.backend.ip);
 [… some other things…]
}
sub vcl_backend_error {
 std.log("backend_used:" + beresp.backend.ip);
 [… some other things…]
}

Then I fetch the entry using
"varnish.backend_name":"%{VCL_Log:backend_used}x"

in my varnishncsa formatted string (output as a JSON, there are many
other fields in there, of course).

Is this correct? Did I missed anything in order to ensure I actually get
the backend IP?

Thanks!

Cheers,

C.