restructure config to allow user credentials to update multiple records

This commit separates user credentials from resource record configs to
allow user credentials to be used for multiple records instead of one.

config.go

@@ -8,18 +8,28 @@ import (
 
 type Config struct {
 	ServerPort uint16     `toml:"port"`
+	Users      []User     `toml:"user"`
 	RRConfigs  []RRConfig `toml:"rrconfig"`
 
+	users     map[string]*User
 	rrconfigs map[string]*RRConfig
 }
 
+type User struct {
+	Username string   `toml:"username"`
+	Password string   `toml:"password"`
+	Records  []string `toml:"records"`
+
+	records map[string]bool
+}
+
 type RRConfig struct {
-	Username   string `toml:"username"`
-	Password   string `toml:"password"`
-	Nameserver string `toml:"nameserver"`
+	Recordname string `toml:"recordname"`
 	Zonename   string `toml:"zonename"`
-	Hostname   string `toml:"hostname"`
-	Tsigkey    string `toml:"tsigkey"`
+	Nameserver string `toml:"nameserver"`
+	Tsigalgo   string `toml:"tsig_algo"`
+	Tsigid     string `toml:"tsig_id"`
+	Tsigkey    string `toml:"tsig_key"`
 	Ttl        int    `toml:"ttl" default:"60"`
 }
 
@@ -37,12 +47,43 @@ func LoadConfig(path string) (*Config, error) {
 		return nil, err
 	}
 
-	cfg.rrconfigs = map[string]*RRConfig{}
-	for _, entry := range cfg.RRConfigs {
-		if _, ok := cfg.rrconfigs[entry.Username]; ok {
-			return nil, fmt.Errorf("Duplicate username detected")
+	// temporary map for preventing duplicate records between users
+	records := make(map[string]bool)
+
+	// populate user map
+	cfg.users = map[string]*User{}
+	for _, user := range cfg.Users {
+		if _, ok := cfg.users[user.Username]; ok {
+			return nil, fmt.Errorf("Duplicate username detected: %s", user.Username)
 		}
-		cfg.rrconfigs[entry.Username] = &entry
+
+		// initialize and populate user.records map
+		user.records = make(map[string]bool)
+		if len(user.Records) <= 0 {
+			return nil, fmt.Errorf("User without records detected: %s", user.Username)
+		}
+		for _, record := range user.Records {
+			// check for duplicate records
+			if records[record] {
+				return nil, fmt.Errorf("Record associated with multiple users detected: %s", record)
+			}
+			// memorize record both in the user as well as in the temporary map
+			user.records[record] = true
+			records[record] = true
+		}
+		cfg.users[user.Username] = &user
+	}
+
+	// populate record map
+	cfg.rrconfigs = map[string]*RRConfig{}
+	for _, record := range cfg.RRConfigs {
+		if !records[record.Recordname] {
+			return nil, fmt.Errorf("Record without associated user detected: %s", record.Recordname)
+		}
+		if _, ok := cfg.rrconfigs[record.Recordname]; ok {
+			return nil, fmt.Errorf("Duplicate record detected: %s", record.Recordname)
+		}
+		cfg.rrconfigs[record.Recordname] = &record
 	}
 	return &cfg, nil
 }