director: Add mail_host.ip_str This avoids having to use net_ip2addr() all the time to convert it into a string.

director: Make director_consistent_hashing=yes mandatory

director: Log vhost count changes and HOST-UP/DOWN

director: Keep per-tag directory

director: Code cleanup - Reorder includes This is required to enable typedef of user_free_hook

director: const mail_host in mail_host_get_tag

global: unsigned int:1 -> bool:1 perl -i -pe 's/unsigned int ([^,:;]+):1;/bool $1:1;/' **/*.[ch]

director: Fixed backend selection when multiple tags were used. The previous algorithm was causing an uneven load for backends. This change breaks compatibility with older director servers that were using tags because of the different selection algorithm. The new director code refuses to run within a cluster with old directors if tags are used.

director: Code cleanup - rename tag to tag_name in mail_host_*() parameters. In preparation for the following changes.

director: Code cleanup - access host->tag via mail_host_get_tag() In preparation for the following changes.

director: Code cleanup - make most mail_host_*() list parameters unnecessary.

director: Remember backends' hostnames and send them in login reply. This allows login processes to verify the remote server's hostname in SSL certificate.

director: Added mail_hosts_hash(), which identifies the current mail_hosts configuration.

director: Don't become desynced if two directors change the same backend in incompatible ways. This would have caused "User hash .. is being redirected to two hosts" errors, which wouldn't easily go away as the directors have a different view of what hosts currently exist.

director: Added "up" vs "down" states and doveadm director up/down commands. These commands are intended to be used by automated watchdogs that detect if backends are up or down. This way the vhost count doesn't get forgotten after server goes down. It also means that admin can manually take down a server by setting its vhost count to 0 without the watchdog automatically bringing it back up.

director: Added support for backend cluster "tags". This allows using a single director ring for multiple backend clusters. By default everything has an empty tag. A passdb lookup can return "director_tag" field containing the wanted tag name. If there aren't any backend servers with the wanted tag, it's treated the same as if there aren't any backend servers available (= wait for 30 secs for a backend and then return temporary failure). Tags can be added to configuration by adding @tag suffix to IPs/hosts. For example: director_mail_servers = 10.0.0.100-10.0.0.110@name1 10.0.0.120@name2 "doveadm director add" can also add tags either with @tag suffix or with -t parameter. "doveadm director status user@domain" requires giving the user's correct tag with -t parameter or the results won't be correct (empty tag's results are shown). Tags can't currently be changed for an existing host without removing it first.

director: Added director_consistent_hashing setting. This should have been the default since the beginning. I didn't thik it was worth the trouble originally because in theory it shouldn't matter much if users jump between multiple backends. But this makes caching behavior worse, especially for systems which are using local cache files.

Renamed network.[ch] to net.[ch]. The function prefixes already started with net_ instead of network_. And icecap wants to use network.h for other purpose. :)

doveadm director status user: Show more ways of what user's potential hosts are. --HG-- branch : HEAD

director: Code cleanup - keep mail hosts in a struct rather than in static variables. --HG-- branch : HEAD

Added initial implementation of a director process (for NFS users). There are still some unimplemented features and bugs. Also changing mail server list doesn't yet make sure that other directors won't assign the same user to a different server at the same time. --HG-- branch : HEAD