AdguardTeam/AdGuardHome · error

json duration is nil

Error message

json duration is nil

What it means

updConfMgr constructs a fresh configuration manager with configmgr.New(ctx, s.confMgrConf); if construction fails the error is wrapped as 'creating config manager'. This is the underlying cause surfaced by Refresh's 'updating configuration manager' error and points at config loading/validation problems rather than service startup.

Source

Thrown at internal/aghhttp/json.go:43

// type check
var _ json.Marshaler = JSONDuration(0)

// MarshalJSON implements the json.Marshaler interface for JSONDuration.  err is
// always nil.
func (d JSONDuration) MarshalJSON() (b []byte, err error) {
	msec := float64(time.Duration(d)) / nsecPerMsec
	b = strconv.AppendFloat(nil, msec, 'f', -1, 64)

	return b, nil
}

// type check
var _ json.Unmarshaler = (*JSONDuration)(nil)

// UnmarshalJSON implements the json.Marshaler interface for *JSONDuration.
func (d *JSONDuration) UnmarshalJSON(b []byte) (err error) {
	if d == nil {
		return fmt.Errorf("json duration is nil")
	}

	msec, err := strconv.ParseFloat(string(b), 64)
	if err != nil {
		return fmt.Errorf("parsing json time: %w", err)
	}

	*d = JSONDuration(int64(msec * nsecPerMsec))

	return nil
}

// JSONTime is a time.Time that can be decoded from JSON and encoded into JSON
// according to our API conventions.
type JSONTime time.Time

// type check
var _ json.Marshaler = JSONTime{}

View on GitHub (pinned to b41aefbe51)

Solutions

1. Look at the wrapped error from configmgr.New for the specific file/key at fault
2. Validate the config file against the current version's schema (check docs/changelog for removed keys)
3. Ensure the config path passed in confMgrConf exists and is readable by the service user
4. Recreate or restore the config file from backup

// Ensure config file is readable and parses before Refresh
if _, err := os.Stat(confPath); err != nil { return err }
if data, err := os.ReadFile(confPath); err != nil { return err } else if !yaml.IsV3Compatible(data) { /* validate */ }

if err := srv.updConfMgr(ctx); err != nil {
    return fmt.Errorf("config manager rebuild failed: %w", errors.Unwrap(err))
}

When it happens

Trigger: Calling Refresh (which calls updConfMgr) when configmgr.New fails: unreadable/missing config file, schema-invalid YAML, or an environment (working directory, env vars) that makes config discovery fail.

Common situations: Config file deleted or renamed while the service runs; config contains keys removed in a newer version; the process's working directory changed so relative config paths break.

Related errors

• duplicated values: %v
• unmarshalling json data into aghalg.NullBool: bad value %q
• networksetup failed to set dns servers: %w
• found no dns servers in %s
• writing conf: %w

AI-assisted analysis of AdguardTeam/AdGuardHome@b41aefbe51 (2026-08-27). Data as JSON: /api/errors/591c44e0bc491569. Report an issue: GitHub.