On Fri, May 09, 2014 at 07:54:33PM -0400, Rajat Chopra wrote: > > No that much. I'm thinking about something. Maps can retrieve the first > > matching prefix using "map_beg". So if you pass "base" to your map, you'll > > have the host+path on input, and take the first matching prefix. Thus, it > > will give you this : > > > > use_backend bk_%[base,map_beg(mapfile)] > > > > The file would contain all the host+path sorted from the longest to the > > shortest (basically just a sort -r) : > > > > domain1/path1/ backend1 > > domain1/path2/ backend2 > > domain1/ backend3 > > domain2/path1/ backend1 > > domain2/ backend4 > > > > The only problem is that the "beg" match needs to iterate over all entries, > > so it will be slower than a tree based lookup, but much faster than running > > 150k rules! > > > > That looks great. > Humble opinion here, or just my discomfort maybe. The map_beg will certainly > solve my current case, but it feels like that a generic user callable > function would offload the myriad other cases that might crop up in the > future. Pretty sure someone will ask for a map_reg down the line - a map with > keys as compiled regexes is compelling.
But it already exists as well. In fact, all the operators you have for the ACLs also exist for the maps. Hmmm I just realized that for whatever reason, map_beg was missing from the map_* table in the doc, which might explain why you didn't find it. Just fixed it. > > And further, I think that with some tweeking, we could make the "beg" match > > use the longest prefix match function of the ebtrees. I remember that > > there's > > something tricky about it related to the string length, but if we need to > > pad > > with a zero or something like this, it might not be a big deal. So maybe in > > the end we could improve the map match to lookup host+uri prefixes faster > > than we do today. > > > > That would be great for URL or Location rewriting! > > > > May I ask about the ETA on this? It's too early for me to know, I need to go down deep into the ebtrees first to see if longest match is compatible with strings storage-wise, then I need to study how patterns are built as trees to see how to do that as well. Possibly it's just one or two days of work once I understand everything. Regards, Willy
