vcl broken after upgrade from 4.1 to 5.0

[Stefan Priebe - Profihost AG]

Hello,

Am 07.08.2018 um 20:10 schrieb Dridi Boukelmoune:
> On Tue, Aug 7, 2018 at 3:27 PM, Stefan Priebe - Profihost AG
> <s.priebe at profihost.ag> wrote:
>> Hello,
>>
>> our varnish vcl is broken after upgrading from 4.1 to 5.0 but i can't
>> find any documentation hint and i also do not find any solution.
>>
>> The old varnish conf uses std.collect to concatenate alls Set-Cookies
>> header from the backend.
>>
>> Then does a lot of "magic" using regsuball.
>>
>> At the end it uses the following Code to split the header into multiple
>> headers again:
>>
>> rebsuball(cookies, ", ", {"
>> Set-Cookies: "})
>>
>> { allows \n / new lines so every new line starts with Set-Cookies: do
>> have multiple Set-Cookies headers.
> 
> Wow, that's like evil clever!

Not my code ;-) I'm just the person who should fix it.

>> This does not seem to work anymore with 5.0 the Set-Cookies Header is
>> still a one line. I was also not able to find the opposite of
>> std.collect to split the line again into multiple headers.
> 
> That's a nice trick, and technically illegal although, well... Good
> job for such a hack!
> 
> Some time after 4.1 std.collect grew support for an optional separator
> other than ", " especially for brain-dead cookie use cases. FYI
> cookies are such a mess because they contain a date formatted with a
> comma followed by a space, but not quoted, so they can't be split like
> other headers such as the Accept* headers.
> 
> To add insult to the injury, HTTP/2 requires cookies to be individual
> headers nevertheless [1] to help HPACK compression effectiveness.
> Since 5.0 is the first release with experimental h2 support, we may
> have tightened headers handling and broken your (illegal but oh so
> clever) hack.

Yes i know but we can't change the backend application so we need to
mess with their cookie stuff inside varnish ;-( and the vendor just says
use varnish 4.1 we don't support 5.X - most probably because the hack
isn't working anymore.

> I don't have time to look [2] closer now, but it would indeed be nice
> to have the reciprocal operation to std.collect, so you could use a
> safe [3] separator to collect, make your changes and then split using
> the same separator.
> 
>     std.collect(beresp.http.set-cookie, "~SEP~");
>     /* do stuff to beresp.http.set-cookie */
>     std.split(beresp.http.set-cookie, "~SEP~");

Yes but i'm sorry i'm unable to provide code. Is there any way to use
something like a loop or recursion? In that case i would be able to
modify a single set-cookie header like we need it.

I also wasn't able to solve it by mod_headers.

Thanks!

Greets,
Stefan