Hi Patrick, On Thu, Oct 06, 2016 at 01:37:35PM -0400, Patrick Hemmer wrote: > While working with the `http-request set-var` (and a few other places, > but primarily here), it would be very useful to be able to use haproxy > format strings to define the variable. > > For example > http-request set-var(txn.foo) fmt(%ci:%cp:%Ts) > Or even > http-request set-var(txn.foo) fmt(%ci:%cp:%Ts),crc32() > > I don't currently see a way to do this, but I could be missing something. > If it's not possible, any chance of getting it added?
I agree we're missing this. I've been willing to concatenate certain fields without being able to do so. The only way to do it right now is to pass via headers which is a pain. I remember contemplating this option a few months ago and finding some technical difficulties with it, related to the error processing during the parsing but I don't remember exactly which ones unfortunately. Probably that should be studied again. We also wanted to work on some converters dealing with a stack allowing an RPN-like syntax for complex data processing. It would remain compatible with what we currently have but offer wider possibilities and cover all use cases supported by the fmt string in addition to some cases where the fmt does not work (eg: binary lookups in tables). We'd then have some strcat() or whatever converters to append the last two strings for example. I believe that this option was also what managed to put the fmt string much lower in the priority queue. Unfortunately everyone willing to work on this has been lacking time and now we have neither of them :-( Thierry, are you still interested in working on the RPN system and more importantly do you think you'll have enough time before the end of this month ? Thanks, Willy
