feat(config): add support for log filters

Signed-off-by: Xe Iaso <me@xeiaso.net>

lib/policy/config/logging.go

@@ -0,0 +1,49 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+)
+
+type Logging struct {
+	Filters []LogFilter `json:"filters,omitempty" yaml:"filters,omitempty"`
+}
+
+func (l *Logging) Valid() error {
+	var errs []error
+
+	for _, lf := range l.Filters {
+		if err := lf.Valid(); err != nil {
+			errs = append(errs, err)
+		}
+	}
+
+	if len(errs) != 0 {
+		return errors.Join(errs...)
+	}
+
+	return nil
+}
+
+type LogFilter struct {
+	Name       string           `json:"name" yaml:"name"`
+	Expression ExpressionOrList `json:"expression" yaml:"expression"`
+}
+
+func (lf LogFilter) Valid() error {
+	var errs []error
+
+	if lf.Name == "" {
+		errs = append(errs, fmt.Errorf("%w: log filter has no name", ErrMissingValue))
+	}
+
+	if err := lf.Expression.Valid(); err != nil {
+		errs = append(errs, err)
+	}
+
+	if len(errs) != 0 {
+		return fmt.Errorf("log filter %q is not valid: %w", lf.Name, errors.Join(errs...))
+	}
+
+	return nil
+}