VCL 4.1 and beresp.backend.ip

Geoff Simmons geoff at
Fri Mar 30 15:42:23 UTC 2018

On 03/29/2018 08:24 PM, Hugues Alary wrote:
> VCL 4.1 retired beresp.backend.ip.
> Is there any way in VCL 4.1 to get the IP Address of the backend used?

No. There have been some thoughts about adding something for "get
backend info" in a future version, which would expose the IP address
among other things, but that's not available for now.

> If not, it means I'll need to use VCL 4.0.
> Is there any reason for me to prefer 4.1 over 4.0?

There may or may not be, depending on your needs.

You'll need VCL 4.1 if:

- You're using Unix domain sockets
- You have more than one listen address, and you want to use
  local.socket and/or local.endpoint in VCL to tell them apart.
- You want to use sess.xid.
- You want to selectively disable ESIs in client responses, and
  prefer to use resp.do_esi rather than req.esi for that.

The *.proto variables are read-only in 4.1; if you want to write to
them, you have to stay with 4.0.

beresp.storage_hint is still around in 4.0, not in 4.1, but you should
be using anyway.

AFAIK that's all of it.

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