tracing: add opentracing for rack and dyndnsd with configurable jaeger-client support and spanmanager

lib/dyndnsd/database.rb

@@ -21,8 +21,10 @@ module Dyndnsd
     end
 
     def save
-      File.open(@db_file, 'w') { |f| JSON.dump(@db, f) }
-      @db_hash = @db.hash
+      Helper.span('database_save') do |_span|
+        File.open(@db_file, 'w') { |f| JSON.dump(@db, f) }
+        @db_hash = @db.hash
+      end
     end
 
     def changed?

lib/dyndnsd/generator/bind.rb

@@ -10,15 +10,15 @@ module Dyndnsd
         @additional_zone_content = config['additional_zone_content']
       end
 
-      def generate(zone)
+      def generate(db)
         out = []
         out << "$TTL #{@ttl}"
         out << "$ORIGIN #{@domain}."
         out << ''
-        out << "@ IN SOA #{@dns} #{@email_addr} ( #{zone['serial']} 3h 5m 1w 1h )"
+        out << "@ IN SOA #{@dns} #{@email_addr} ( #{db['serial']} 3h 5m 1w 1h )"
         out << "@ IN NS #{@dns}"
         out << ''
-        zone['hosts'].each do |hostname, ips|
+        db['hosts'].each do |hostname, ips|
           ips.each do |ip|
             ip = IPAddr.new(ip).native
             type = ip.ipv6? ? 'AAAA' : 'A'

lib/dyndnsd/helper.rb

@@ -17,5 +17,25 @@ module Dyndnsd
     rescue ArgumentError
       return false
     end
+
+    def self.user_allowed?(username, password, users)
+      (users.key? username) && (users[username]['password'] == password)
+    end
+
+    def self.changed?(hostname, myips, hosts)
+      # myips order is always deterministic
+      (!hosts.include? hostname) || (hosts[hostname] != myips)
+    end
+
+    def self.span(operation, &block)
+      span = OpenTracing.start_span(operation)
+      span.set_tag('component', 'dyndnsd')
+      span.set_tag('span.kind', 'server')
+      begin
+        block.call(span)
+      ensure
+        span.finish
+      end
+    end
   end
 end

lib/dyndnsd/updater/command_with_bind_zone.rb

@@ -9,14 +9,19 @@ module Dyndnsd
       end
 
       def update(zone)
-        # write zone file in bind syntax
-        File.open(@zone_file, 'w') { |f| f.write(@generator.generate(zone)) }
-        # call user-defined command
-        pid = fork do
-          exec @command
+        Helper.span('updater_update') do |span|
+          span.set_tag('dyndnsd.updater.name', self.class.name.split('::').last)
+
+          # write zone file in bind syntax
+          File.open(@zone_file, 'w') { |f| f.write(@generator.generate(zone)) }
+          # call user-defined command
+          pid = fork do
+            exec @command
+          end
+
+          # detach so children don't become zombies
+          Process.detach(pid)
         end
-        # detach so children don't become zombies
-        Process.detach(pid)
       end
     end
   end