diff options
| -rw-r--r-- | net/resolvers/service.lua | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/net/resolvers/service.lua b/net/resolvers/service.lua new file mode 100644 index 00000000..736a838b --- /dev/null +++ b/net/resolvers/service.lua @@ -0,0 +1,57 @@ +local adns = require "net.adns"; +local basic = require "net.resolvers.basic"; + +local methods = {}; +local resolver_mt = { __index = methods }; + +-- Find the next target to connect to, and +-- pass it to cb() +function methods:next(cb) + if self.targets then + if #self.targets == 0 then + cb(nil); + return; + end + local next_target = table.remove(self.targets, 1); + self.resolver = basic.new(unpack(next_target, 1, 4)); + self.resolver:next(function (...) + if ... == nil then + self:next(cb); + else + cb(...); + end + end); + return; + end + + local targets = {}; + local function ready() + self.targets = targets; + self:next(cb); + end + + -- Resolve DNS to target list + local dns_resolver = adns.resolver(); + dns_resolver:lookup(function (answer) + if answer then + table.sort(answer, function (a, b) return a.priority > b.priority end); + for _, record in ipairs(answer) do + table.insert(targets, { record.srv.target, record.srv.port, self.conn_type, self.extra }); + end + end + ready(); + end, "_" .. self.service .. "._" .. self.conn_type .. "." .. self.domain, "SRV", "IN"); +end + +local function new(domain, service, conn_type, extra) + return setmetatable({ + domain = domain; + service = service; + conn_type = conn_type or "tcp"; + extra = extra; + }, resolver_mt); +end + +return { + new = new; +}; |