add auth support

internal/settings/settings.go

@@ -1,6 +1,7 @@
 package settings
 
 import (
+	"encoding/base64"
 	"errors"
 	"fmt"
 	"log/slog"
@@ -18,6 +19,20 @@ var (
 	postgresKVPasswordPattern          = regexp.MustCompile(`(?i)(\bpassword\s*=\s*)(?:'[^']*'|"[^"]*"|[^\s]+)`)
 )
 
+const (
+	authModeDisabled = "disabled"
+	authModeOptional = "optional"
+	authModeRequired = "required"
+
+	authRoleAdmin  = "admin"
+	authRoleViewer = "viewer"
+
+	defaultAuthTokenLifespanMinutes = 120
+	defaultAuthJWTIssuer            = "vctp"
+	defaultAuthJWTAudience          = "vctp-api"
+	defaultAuthClockSkewSeconds     = 60
+)
+
 type Settings struct {
 	SettingsPath string
 	Logger       *slog.Logger
@@ -50,6 +65,21 @@ type SettingsYML struct {
 		VcenterPassword                  string               `yaml:"vcenter_password"`
 		VcenterInsecure                  bool                 `yaml:"vcenter_insecure"`
 		EnableLegacyAPI                  bool                 `yaml:"enable_legacy_api"`
+		AuthEnabled                      bool                 `yaml:"auth_enabled"`
+		AuthMode                         string               `yaml:"auth_mode"`
+		AuthJWTSigningKey                string               `yaml:"auth_jwt_signing_key"`
+		AuthTokenLifespanMinutes         int                  `yaml:"auth_token_lifespan_minutes"`
+		AuthJWTIssuer                    string               `yaml:"auth_jwt_issuer"`
+		AuthJWTAudience                  string               `yaml:"auth_jwt_audience"`
+		AuthClockSkewSeconds             int                  `yaml:"auth_clock_skew_seconds"`
+		AuthGroupRoleMappings            map[string]string    `yaml:"auth_group_role_mappings"`
+		LDAPGroups                       []string             `yaml:"ldap_groups"`
+		LDAPBindAddress                  string               `yaml:"ldap_bind_address"`
+		LDAPBaseDN                       string               `yaml:"ldap_base_dn"`
+		LDAPTrustCertFile                string               `yaml:"ldap_trust_cert_file"`
+		LDAPDisableValidation            bool                 `yaml:"ldap_disable_validation"`
+		LDAPInsecure                     bool                 `yaml:"ldap_insecure"`
+		EnablePprof                      bool                 `yaml:"enable_pprof"`
 		VcenterEventPollingSeconds       int                  `yaml:"vcenter_event_polling_seconds"`
 		VcenterInventoryPollingSeconds   int                  `yaml:"vcenter_inventory_polling_seconds"`
 		VcenterInventorySnapshotSeconds  int                  `yaml:"vcenter_inventory_snapshot_seconds"`
@@ -112,6 +142,9 @@ func (s *Settings) ReadYMLSettings() error {
 	if err := d.Decode(&settings); err != nil {
 		return fmt.Errorf("unable to decode settings file : '%s'", err)
 	}
+	if err := applyDefaultsAndValidateSettings(&settings); err != nil {
+		return fmt.Errorf("invalid settings file: %w", err)
+	}
 
 	// Avoid logging sensitive fields (e.g., credentials).
 	redacted := settings
@@ -119,6 +152,9 @@ func (s *Settings) ReadYMLSettings() error {
 	if redacted.Settings.EncryptionKey != "" {
 		redacted.Settings.EncryptionKey = "REDACTED"
 	}
+	if redacted.Settings.AuthJWTSigningKey != "" {
+		redacted.Settings.AuthJWTSigningKey = "REDACTED"
+	}
 	if redacted.Settings.DatabaseURL != "" {
 		redacted.Settings.DatabaseURL = redactDatabaseURL(redacted.Settings.DatabaseURL)
 	}
@@ -189,3 +225,140 @@ func secureSettingsFileMode(mode os.FileMode) os.FileMode {
 	secured |= 0o600
 	return secured
 }
+
+func applyDefaultsAndValidateSettings(cfg *SettingsYML) error {
+	if cfg == nil {
+		return errors.New("settings config is nil")
+	}
+	s := &cfg.Settings
+
+	s.AuthMode = strings.ToLower(strings.TrimSpace(s.AuthMode))
+	if s.AuthMode == "" {
+		s.AuthMode = authModeDisabled
+	}
+	if s.AuthTokenLifespanMinutes == 0 {
+		s.AuthTokenLifespanMinutes = defaultAuthTokenLifespanMinutes
+	}
+	s.AuthJWTIssuer = strings.TrimSpace(s.AuthJWTIssuer)
+	if s.AuthJWTIssuer == "" {
+		s.AuthJWTIssuer = defaultAuthJWTIssuer
+	}
+	s.AuthJWTAudience = strings.TrimSpace(s.AuthJWTAudience)
+	if s.AuthJWTAudience == "" {
+		s.AuthJWTAudience = defaultAuthJWTAudience
+	}
+	if s.AuthClockSkewSeconds == 0 {
+		s.AuthClockSkewSeconds = defaultAuthClockSkewSeconds
+	}
+	s.AuthJWTSigningKey = strings.TrimSpace(s.AuthJWTSigningKey)
+	s.LDAPBindAddress = strings.TrimSpace(s.LDAPBindAddress)
+	s.LDAPBaseDN = strings.TrimSpace(s.LDAPBaseDN)
+	s.LDAPTrustCertFile = strings.TrimSpace(s.LDAPTrustCertFile)
+	s.LDAPGroups = compactTrimmedStrings(s.LDAPGroups)
+
+	if !isValidAuthMode(s.AuthMode) {
+		return fmt.Errorf("settings.auth_mode must be one of %q, %q, %q", authModeDisabled, authModeOptional, authModeRequired)
+	}
+	if s.AuthTokenLifespanMinutes <= 0 {
+		return errors.New("settings.auth_token_lifespan_minutes must be greater than 0")
+	}
+	if s.AuthClockSkewSeconds < 0 {
+		return errors.New("settings.auth_clock_skew_seconds must be >= 0")
+	}
+
+	if len(s.AuthGroupRoleMappings) > 0 {
+		normalized := make(map[string]string, len(s.AuthGroupRoleMappings))
+		for groupDN, role := range s.AuthGroupRoleMappings {
+			groupDN = strings.TrimSpace(groupDN)
+			role = strings.ToLower(strings.TrimSpace(role))
+			if groupDN == "" {
+				return errors.New("settings.auth_group_role_mappings contains an empty group DN key")
+			}
+			if !isValidAuthRole(role) {
+				return fmt.Errorf("settings.auth_group_role_mappings[%q] has unsupported role %q", groupDN, role)
+			}
+			normalized[groupDN] = role
+		}
+		s.AuthGroupRoleMappings = normalized
+	}
+
+	if !s.AuthEnabled {
+		return nil
+	}
+	if s.AuthMode == authModeDisabled {
+		return errors.New("settings.auth_mode must be optional or required when settings.auth_enabled=true")
+	}
+	if s.AuthJWTSigningKey == "" {
+		return errors.New("settings.auth_jwt_signing_key is required when settings.auth_enabled=true")
+	}
+	decodedKey, err := decodeBase64(s.AuthJWTSigningKey)
+	if err != nil {
+		return errors.New("settings.auth_jwt_signing_key must be valid base64")
+	}
+	if len(decodedKey) == 0 {
+		return errors.New("settings.auth_jwt_signing_key cannot decode to an empty value")
+	}
+	if s.LDAPBindAddress == "" {
+		return errors.New("settings.ldap_bind_address is required when settings.auth_enabled=true")
+	}
+	if s.LDAPBaseDN == "" {
+		return errors.New("settings.ldap_base_dn is required when settings.auth_enabled=true")
+	}
+	if len(s.AuthGroupRoleMappings) == 0 {
+		return errors.New("settings.auth_group_role_mappings must define at least one mapping when settings.auth_enabled=true")
+	}
+
+	return nil
+}
+
+func isValidAuthMode(mode string) bool {
+	switch mode {
+	case authModeDisabled, authModeOptional, authModeRequired:
+		return true
+	default:
+		return false
+	}
+}
+
+func isValidAuthRole(role string) bool {
+	switch role {
+	case authRoleAdmin, authRoleViewer:
+		return true
+	default:
+		return false
+	}
+}
+
+func decodeBase64(value string) ([]byte, error) {
+	encodings := []*base64.Encoding{
+		base64.StdEncoding,
+		base64.RawStdEncoding,
+		base64.URLEncoding,
+		base64.RawURLEncoding,
+	}
+	for _, encoding := range encodings {
+		decoded, err := encoding.DecodeString(value)
+		if err == nil {
+			return decoded, nil
+		}
+	}
+	return nil, errors.New("invalid base64 encoding")
+}
+
+func compactTrimmedStrings(values []string) []string {
+	if len(values) == 0 {
+		return nil
+	}
+	out := make([]string, 0, len(values))
+	for _, value := range values {
+		trimmed := strings.TrimSpace(value)
+		if trimmed == "" {
+			continue
+		}
+		out = append(out, trimmed)
+	}
+	if len(out) == 0 {
+		return nil
+	}
+	return out
+}