func()

in confgenerator/filter/internal/ast/ast.go [441:487]

• 32 lines of code
• 10 McCabe index (conditional complexity)

func (r Restriction) FluentConfig(tag, key string) ([]fluentbit.Component, string) {
	lhs, _ := r.LHS.LuaAccessor(false)
	rhsQuoted := LuaQuote(r.RHS)
	rhsRegex := escapeWhitespaceFluentBit(r.RHS)

	// TODO: Add support for numeric comparisons

	var expr string

	switch r.Operator {
	case "GLOBAL", "<", "<=", ">", ">=":
		panic(fmt.Errorf("unimplemented operator: %s", r.Operator))
	case ":":
		// substring match, case insensitive
		expr = fmt.Sprintf(`(string.find(string.lower(tostring(v)), string.lower(%s), 1, false) ~= nil)`, rhsQuoted)
	case "=~", "!~":
		// regex match, case sensitive

		// TODO: Re-implement using Lua once regex is supported. Lua has been shown to perform better
		// than the next/modify/lift pattern used here, but we are unable to use Lua for now since
		// it does not yet support regex.

		c := modify(tag, key)
		lhsRA, err := r.LHS.RecordAccessor()
		if err != nil {
			panic(fmt.Errorf("LHS %v couldn't parse: %w", r.LHS, err))
		}
		if r.Operator == "=~" {
			c.Config["Condition"] = cond("Key_value_matches", lhsRA, rhsRegex)
		} else {
			c.OrderedConfig = append(c.OrderedConfig, [2]string{"Condition", cond("Key_value_does_not_match", lhsRA, rhsRegex)})
		}
		return []fluentbit.Component{c}, fmt.Sprintf(`(record[%s] ~= nil)`, LuaQuote(key))
	case "=":
		// equality, case insensitive
		expr = fmt.Sprintf(`(string.lower(tostring(v)) == string.lower(%s))`, rhsQuoted)
	case "!=":
		// inequality, case insensitive
		expr = fmt.Sprintf(`(string.lower(tostring(v)) ~= string.lower(%s))`, rhsQuoted)
	}
	if expr != "" {
		// All comparisons involving a missing field are false
		return nil, fmt.Sprintf(`(function(v) if v == nil then return false end return %s end)(%s)`, expr, lhs)
	}
	// This is all the supported operators.
	panic(fmt.Errorf("unknown operator: %s", r.Operator))
}