Initial commit.

internal/configuration/configuration.go

@@ -0,0 +1,54 @@
+package configuration
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+)
+
+var (
+	// ErrConfigurationError can be used to determine if received error was
+	// about invalid configuration.
+	ErrConfigurationError = errors.New("configuration")
+
+	// DomainPostfix is a string that will be added to parsed domain if not already
+	// present. E.g. with DomainPostfix = "example.com" for parsed domain "host-1"
+	// it will be added and parsed domain will be in form "host-1.example.com", but
+	// for parsed domain "host-2.example.com" it won't be added as it is already
+	// present in the very end.
+	DomainPostfix string
+	// HostsFilePath defines a path from which hosts file will be used for parsing.
+	HostsFilePath string
+	// StorageToUse defines storage translator will use for updating data.
+	StorageToUse string
+)
+
+// Initialize initializes configuration subsystem.
+func Initialize() {
+	flag.StringVar(&DomainPostfix, "domain-postfix", "", "Postfix to append to domain. Some storages requires this parameter to be filled.")
+	flag.StringVar(&HostsFilePath, "hosts-file", "", "Path to hosts file to parse.")
+	flag.StringVar(&StorageToUse, "storage", "", "Storage to use. Currently supported: 'powerdns'.")
+
+	initializePowerDNS()
+}
+
+func Parse() {
+	flag.Parse()
+}
+
+// Validate validates configuration data and returns error is something isn't right.
+func Validate() error {
+	if HostsFilePath == "" {
+		return fmt.Errorf("%w: empty hosts file path", ErrConfigurationError)
+	}
+
+	if StorageToUse == "" {
+		return fmt.Errorf("%w: no storage name was provided", ErrConfigurationError)
+	}
+
+	if err := validatePowerDNS(); err != nil {
+		return err
+	}
+
+	return nil
+}

internal/configuration/powerdns.go

@@ -0,0 +1,43 @@
+package configuration
+
+import (
+	"flag"
+	"fmt"
+	"strings"
+)
+
+var (
+	// PowerDNSAPIKey defines API key for PowerDNS HTTP API.
+	PowerDNSAPIKey string
+	// PowerDNSURI defines URL for PowerDNS HTTP API.
+	PowerDNSURI string
+)
+
+func initializePowerDNS() {
+	flag.StringVar(&PowerDNSAPIKey, "powerdns-api-key", "", "API key for PowerDNS HTTP API.")
+	flag.StringVar(&PowerDNSURI, "powerdns-uri", "", "URI for PowerDNS API. Should be in 'proto://ADDR:PORT' form.")
+}
+
+func validatePowerDNS() error {
+	if strings.ToLower(StorageToUse) != "powerdns" {
+		return nil
+	}
+
+	// PowerDNS storage requires DomainSuffix to determine zone name to update.
+	if DomainPostfix == "" {
+		return fmt.Errorf("%w: domain postfix isn't filled which is required by PowerDNS storage", ErrConfigurationError)
+	}
+
+	if PowerDNSAPIKey == "" {
+		return fmt.Errorf("%w: no PowerDNS API key was provided", ErrConfigurationError)
+	}
+
+	if PowerDNSURI == "" {
+		return fmt.Errorf("%w: no PowerDNS HTTP API server URI provided", ErrConfigurationError)
+	}
+
+	// Hack: trim slashes in end.
+	PowerDNSURI = strings.TrimRight(PowerDNSURI, "/")
+
+	return nil
+}