| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | package pipeline |
| 4 | |
| 5 | import ( |
| 6 | "errors" |
| 7 | "fmt" |
| 8 | "strings" |
| 9 | |
| 10 | "github.com/netdata/netdata/go/plugins/plugin/agent/discovery/sd/model" |
| 11 | ) |
| 12 | |
| 13 | type selector interface { |
| 14 | matches(model.Tags) bool |
| 15 | } |
| 16 | |
| 17 | type ( |
| 18 | exactSelector string |
| 19 | trueSelector struct{} |
| 20 | negSelector struct{ selector } |
| 21 | orSelector struct{ lhs, rhs selector } |
| 22 | andSelector struct{ lhs, rhs selector } |
| 23 | ) |
| 24 | |
| 25 | func (s exactSelector) matches(tags model.Tags) bool { _, ok := tags[string(s)]; return ok } |
| 26 | func (s trueSelector) matches(model.Tags) bool { return true } |
| 27 | func (s negSelector) matches(tags model.Tags) bool { return !s.selector.matches(tags) } |
| 28 | func (s orSelector) matches(tags model.Tags) bool { return s.lhs.matches(tags) || s.rhs.matches(tags) } |
| 29 | func (s andSelector) matches(tags model.Tags) bool { return s.lhs.matches(tags) && s.rhs.matches(tags) } |
| 30 | |
| 31 | func (s exactSelector) String() string { return "{" + string(s) + "}" } |
| 32 | func (s negSelector) String() string { return "{!" + stringify(s.selector) + "}" } |
| 33 | func (s trueSelector) String() string { return "{*}" } |
| 34 | func (s orSelector) String() string { return "{" + stringify(s.lhs) + "|" + stringify(s.rhs) + "}" } |
| 35 | func (s andSelector) String() string { return "{" + stringify(s.lhs) + ", " + stringify(s.rhs) + "}" } |
| 36 | func stringify(sr selector) string { return strings.Trim(fmt.Sprintf("%s", sr), "{}") } |
| 37 | |
| 38 | func parseSelector(line string) (sr selector, err error) { |
| 39 | words := strings.Fields(line) |
| 40 | if len(words) == 0 { |
| 41 | return trueSelector{}, nil |
| 42 | } |
| 43 | |
| 44 | var srs []selector |
| 45 | for _, word := range words { |
| 46 | if idx := strings.IndexByte(word, '|'); idx > 0 { |
| 47 | sr, err = parseOrSelectorWord(word) |
| 48 | } else { |
| 49 | sr, err = parseSingleSelectorWord(word) |
| 50 | } |
| 51 | if err != nil { |
| 52 | return nil, fmt.Errorf("selector '%s' contains selector '%s' with forbidden symbol", line, word) |
| 53 | } |
| 54 | srs = append(srs, sr) |
| 55 | } |
| 56 | |
| 57 | switch len(srs) { |
| 58 | case 0: |
| 59 | return trueSelector{}, nil |
| 60 | case 1: |
| 61 | return srs[0], nil |
| 62 | default: |
| 63 | return newAndSelector(srs[0], srs[1], srs[2:]...), nil |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | func parseOrSelectorWord(orWord string) (sr selector, err error) { |
| 68 | var srs []selector |
| 69 | for word := range strings.SplitSeq(orWord, "|") { |
| 70 | if sr, err = parseSingleSelectorWord(word); err != nil { |
| 71 | return nil, err |
| 72 | } |
| 73 | srs = append(srs, sr) |
| 74 | } |
| 75 | switch len(srs) { |
| 76 | case 0: |
| 77 | return trueSelector{}, nil |
| 78 | case 1: |
| 79 | return srs[0], nil |
| 80 | default: |
| 81 | return newOrSelector(srs[0], srs[1], srs[2:]...), nil |
| 82 | } |
| 83 | } |
| 84 | |
| 85 | func parseSingleSelectorWord(word string) (selector, error) { |
| 86 | if len(word) == 0 { |
| 87 | return nil, errors.New("empty word") |
| 88 | } |
| 89 | neg := word[0] == '!' |
| 90 | if neg { |
| 91 | word = word[1:] |
| 92 | } |
| 93 | if len(word) == 0 { |
| 94 | return nil, errors.New("empty word") |
| 95 | } |
| 96 | if word != "*" && !isSelectorWordValid(word) { |
| 97 | return nil, errors.New("forbidden symbol") |
| 98 | } |
| 99 | |
| 100 | var sr selector |
| 101 | switch word { |
| 102 | case "*": |
| 103 | sr = trueSelector{} |
| 104 | default: |
| 105 | sr = exactSelector(word) |
| 106 | } |
| 107 | if neg { |
| 108 | return negSelector{sr}, nil |
| 109 | } |
| 110 | return sr, nil |
| 111 | } |
| 112 | |
| 113 | func newAndSelector(lhs, rhs selector, others ...selector) selector { |
| 114 | m := andSelector{lhs: lhs, rhs: rhs} |
| 115 | switch len(others) { |
| 116 | case 0: |
| 117 | return m |
| 118 | default: |
| 119 | return newAndSelector(m, others[0], others[1:]...) |
| 120 | } |
| 121 | } |
| 122 | |
| 123 | func newOrSelector(lhs, rhs selector, others ...selector) selector { |
| 124 | m := orSelector{lhs: lhs, rhs: rhs} |
| 125 | switch len(others) { |
| 126 | case 0: |
| 127 | return m |
| 128 | default: |
| 129 | return newOrSelector(m, others[0], others[1:]...) |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | func isSelectorWordValid(word string) bool { |
| 134 | // valid: |
| 135 | // * |
| 136 | // ^[a-zA-Z][a-zA-Z0-9=_.]*$ |
| 137 | if len(word) == 0 { |
| 138 | return false |
| 139 | } |
| 140 | if word == "*" { |
| 141 | return true |
| 142 | } |
| 143 | for i, b := range word { |
| 144 | switch { |
| 145 | case b >= 'a' && b <= 'z': |
| 146 | case b >= 'A' && b <= 'Z': |
| 147 | case b >= '0' && b <= '9' && i > 0: |
| 148 | case (b == '=' || b == '_' || b == '.') && i > 0: |
| 149 | default: |
| 150 | return false |
| 151 | } |
| 152 | } |
| 153 | return true |
| 154 | } |