| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | package selectorcore |
| 4 | |
| 5 | import ( |
| 6 | "fmt" |
| 7 | "regexp" |
| 8 | "strings" |
| 9 | |
| 10 | "github.com/netdata/netdata/go/plugins/pkg/matcher" |
| 11 | ) |
| 12 | |
| 13 | var ( |
| 14 | reLV = regexp.MustCompile(`^(?P<label_name>[a-zA-Z0-9_]+)(?P<op>=~|!~|=\*|!\*|=|!=)"(?P<pattern>.+)"$`) |
| 15 | ) |
| 16 | |
| 17 | // Parse parses one selector expression. |
| 18 | func Parse(expr string) (Selector, error) { |
| 19 | terms, err := splitSelectorTerms(unsugarExpr(expr)) |
| 20 | if err != nil { |
| 21 | return nil, err |
| 22 | } |
| 23 | |
| 24 | srs := make([]Selector, 0, len(terms)) |
| 25 | for _, term := range terms { |
| 26 | sr, err := parseSelector(term) |
| 27 | if err != nil { |
| 28 | return nil, err |
| 29 | } |
| 30 | srs = append(srs, sr) |
| 31 | } |
| 32 | |
| 33 | switch len(srs) { |
| 34 | case 0: |
| 35 | return nil, nil |
| 36 | case 1: |
| 37 | return srs[0], nil |
| 38 | default: |
| 39 | return And(srs[0], srs[1], srs[2:]...), nil |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | func parseSelector(line string) (Selector, error) { |
| 44 | sub := reLV.FindStringSubmatch(strings.TrimSpace(line)) |
| 45 | if sub == nil { |
| 46 | return nil, fmt.Errorf("invalid selector syntax: '%s'", line) |
| 47 | } |
| 48 | |
| 49 | name, op, pattern := sub[1], sub[2], strings.Trim(sub[3], "\"") |
| 50 | |
| 51 | var m matcher.Matcher |
| 52 | var err error |
| 53 | |
| 54 | switch op { |
| 55 | case OpEqual, OpNegEqual: |
| 56 | m, err = matcher.NewStringMatcher(pattern, true, true) |
| 57 | case OpRegexp, OpNegRegexp: |
| 58 | m, err = matcher.NewRegExpMatcher(pattern) |
| 59 | case OpSimplePatterns, OpNegSimplePatterns: |
| 60 | m, err = matcher.NewSimplePatternsMatcher(pattern) |
| 61 | default: |
| 62 | err = fmt.Errorf("unknown matching operator: %s", op) |
| 63 | } |
| 64 | if err != nil { |
| 65 | return nil, err |
| 66 | } |
| 67 | |
| 68 | sr := labelSelector{name: name, m: m} |
| 69 | if strings.HasPrefix(op, "!") { |
| 70 | return Not(sr), nil |
| 71 | } |
| 72 | return sr, nil |
| 73 | } |
| 74 | |
| 75 | func unsugarExpr(expr string) string { |
| 76 | // name => __name__=*"name" |
| 77 | // name{label="value"} => __name__=*"name",label="value" |
| 78 | // {label="value"} => label="value" |
| 79 | expr = strings.TrimSpace(expr) |
| 80 | if expr == "" { |
| 81 | return "" |
| 82 | } |
| 83 | |
| 84 | switch idx := strings.IndexByte(expr, '{'); { |
| 85 | case idx == -1: |
| 86 | expr = fmt.Sprintf(`%s%s"%s"`, |
| 87 | MetricNameLabel, |
| 88 | OpSimplePatterns, |
| 89 | strings.TrimSpace(expr), |
| 90 | ) |
| 91 | case idx == 0: |
| 92 | expr = strings.Trim(expr, "{}") |
| 93 | default: |
| 94 | expr = fmt.Sprintf(`%s%s"%s",%s`, |
| 95 | MetricNameLabel, |
| 96 | OpSimplePatterns, |
| 97 | strings.TrimSpace(expr[:idx]), |
| 98 | strings.Trim(expr[idx:], "{}"), |
| 99 | ) |
| 100 | } |
| 101 | return expr |
| 102 | } |
| 103 | |
| 104 | func splitSelectorTerms(expr string) ([]string, error) { |
| 105 | expr = strings.TrimSpace(expr) |
| 106 | if expr == "" { |
| 107 | return nil, nil |
| 108 | } |
| 109 | |
| 110 | var ( |
| 111 | terms []string |
| 112 | buf strings.Builder |
| 113 | inQuotes bool |
| 114 | escapePending bool |
| 115 | seenComma bool |
| 116 | ) |
| 117 | |
| 118 | for _, r := range expr { |
| 119 | switch { |
| 120 | case escapePending: |
| 121 | escapePending = false |
| 122 | buf.WriteRune(r) |
| 123 | case r == '\\': |
| 124 | escapePending = true |
| 125 | buf.WriteRune(r) |
| 126 | case r == '"': |
| 127 | inQuotes = !inQuotes |
| 128 | buf.WriteRune(r) |
| 129 | case r == ',' && !inQuotes: |
| 130 | seenComma = true |
| 131 | part := strings.TrimSpace(buf.String()) |
| 132 | if part == "" { |
| 133 | return nil, fmt.Errorf("invalid selector syntax: empty matcher around comma") |
| 134 | } |
| 135 | terms = append(terms, part) |
| 136 | buf.Reset() |
| 137 | default: |
| 138 | buf.WriteRune(r) |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | if inQuotes { |
| 143 | return nil, fmt.Errorf("invalid selector syntax: unterminated quote") |
| 144 | } |
| 145 | |
| 146 | last := strings.TrimSpace(buf.String()) |
| 147 | if last == "" { |
| 148 | if seenComma { |
| 149 | return nil, fmt.Errorf("invalid selector syntax: trailing comma") |
| 150 | } |
| 151 | return nil, nil |
| 152 | } |
| 153 | terms = append(terms, last) |
| 154 | return terms, nil |
| 155 | } |