vcl_error with streaming

Artur Bergman sky at
Thu Jan 12 18:34:18 CET 2012

Why can't vcl_error/vcl_synth go through deliver?

We have a fair amount of stuff in deliver that would have to be replicated.


On Jan 12, 2012, at 3:58 AM, Tollef Fog Heen wrote:

> We have talked a bit about how vcl_error interacts with streaming, and
> the idea so far has been to remove vcl_error and add a synthetic
> capability to vcl_deliver.  Last night, phk had an idea and he and I had
> a chat about how we could go about not getting rid of vcl_error and its
> implications.  Further, we had a bit of discussion in the office this
> morning about this and some sort of consensus emerged.
> - vcl_error stays, but delivers directly and does not pass vcl_deliver.
>  vcl_error is an error handler and should not be used for redirects and
>  similar
> - vcl_synth is added, for any kind of synthetic content, typically
>  redirects.  The default vcl_synth can include the necessary couple of
>  lines to handle redirects directly, so you can then just do
>  return(synth(301, "")); wherever you want to
>  redirect.
> Both vcl_error and vcl_synth terminate and does not go through
> vcl_deliver, vcl_fetch or any other place.
> Does this sound roughly sane (and could Kristian and Martin please
> correct any inaccuracies)?
> -- 
> Tollef Fog Heen
> Technical lead, Varnish Software
> t: +47 21 98 92 64
> _______________________________________________
> varnish-dev mailing list
> varnish-dev at

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