Function Rule

pkg/schema/builder.go:79–120

Rule is a function that generates a rule definition given a name, a map of argument names to attribute types, and an expression string. The expression string is compiled and transformed to a checked expression.

(name string, arguments map[string]base.AttributeType, expression string)

// a map of argument names to attribute types, and an expression string.
// The expression string is compiled and transformed to a checked expression.
func Rule(name string, arguments map[string]base.AttributeType, expression string) *base.RuleDefinition {
	// Initialize an empty slice of environment options.
	var envOptions []cel.EnvOption
	envOptions = append(envOptions, cel.Variable("context", cel.DynType))

	// Iterate through each argument.
	for name, ty := range arguments {
		// Convert the attribute type to CEL type.
		cType, err := utils.GetCelType(ty)
		if err != nil {
			return nil
		}

		// Append a new environment option which represents a variable and its type.
		envOptions = append(envOptions, cel.Variable(name, cType))
	}

	// Create a new CEL environment with the environment options.
	env, err := cel.NewEnv(envOptions...)
	if err != nil {
		return nil
	}

	// Compile the given expression string.
	compiledExp, issues := env.Compile(expression)
	if issues != nil && issues.Err() != nil {
		return nil
	}

	// Convert the compiled expression to a checked expression.
	expr, err := cel.AstToCheckedExpr(compiledExp)
	if err != nil {
		return nil
	}

	// Return a new rule definition with the given name, arguments, and the checked expression.
	return &base.RuleDefinition{
		Name:       name,
		Arguments:  arguments,
		Expression: expr,
	}
}

// Rules - Rules builder
func Rules(defs ...*base.RuleDefinition) []*base.RuleDefinition {