| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | package selectorcore |
| 4 | |
| 5 | import ( |
| 6 | "fmt" |
| 7 | "slices" |
| 8 | "strings" |
| 9 | ) |
| 10 | |
| 11 | // Meta contains selector metadata needed by template compilers/engines. |
| 12 | type Meta struct { |
| 13 | MetricNames []string |
| 14 | ConstrainedLabelKeys []string |
| 15 | } |
| 16 | |
| 17 | // Compiled is a selector with stable metadata. |
| 18 | type Compiled interface { |
| 19 | Selector |
| 20 | Meta() Meta |
| 21 | } |
| 22 | |
| 23 | type compiledSelector struct { |
| 24 | Selector |
| 25 | meta Meta |
| 26 | } |
| 27 | |
| 28 | func (c compiledSelector) Meta() Meta { |
| 29 | return Meta{ |
| 30 | MetricNames: append([]string(nil), c.meta.MetricNames...), |
| 31 | ConstrainedLabelKeys: append([]string(nil), c.meta.ConstrainedLabelKeys...), |
| 32 | } |
| 33 | } |
| 34 | |
| 35 | // ParseCompiled parses a selector expression and returns matcher + metadata. |
| 36 | func ParseCompiled(expr string) (Compiled, error) { |
| 37 | expanded := unsugarExpr(expr) |
| 38 | terms, err := splitSelectorTerms(expanded) |
| 39 | if err != nil { |
| 40 | return nil, err |
| 41 | } |
| 42 | if len(terms) == 0 { |
| 43 | return nil, fmt.Errorf("invalid selector syntax: %q", expr) |
| 44 | } |
| 45 | |
| 46 | parts := make([]Selector, 0, len(terms)) |
| 47 | metricNames := map[string]struct{}{} |
| 48 | keys := map[string]struct{}{} |
| 49 | |
| 50 | for _, term := range terms { |
| 51 | sel, err := parseSelector(term) |
| 52 | if err != nil { |
| 53 | return nil, err |
| 54 | } |
| 55 | parts = append(parts, sel) |
| 56 | |
| 57 | sub := reLV.FindStringSubmatch(strings.TrimSpace(term)) |
| 58 | if sub == nil { |
| 59 | return nil, fmt.Errorf("invalid selector syntax: %q", term) |
| 60 | } |
| 61 | name, op, pattern := sub[1], sub[2], strings.Trim(sub[3], "\"") |
| 62 | if name == MetricNameLabel { |
| 63 | for _, mn := range metricNameCandidates(op, pattern) { |
| 64 | metricNames[mn] = struct{}{} |
| 65 | } |
| 66 | continue |
| 67 | } |
| 68 | keys[name] = struct{}{} |
| 69 | } |
| 70 | |
| 71 | out := compiledSelector{Selector: parts[0]} |
| 72 | if len(parts) > 1 { |
| 73 | out.Selector = And(parts[0], parts[1], parts[2:]...) |
| 74 | } |
| 75 | out.meta = Meta{ |
| 76 | MetricNames: mapKeysSorted(metricNames), |
| 77 | ConstrainedLabelKeys: mapKeysSorted(keys), |
| 78 | } |
| 79 | return out, nil |
| 80 | } |
| 81 | |
| 82 | func metricNameCandidates(op, pattern string) []string { |
| 83 | switch op { |
| 84 | case OpEqual: |
| 85 | return []string{pattern} |
| 86 | case OpSimplePatterns: |
| 87 | if strings.ContainsAny(pattern, "*?[]") { |
| 88 | return nil |
| 89 | } |
| 90 | return []string{pattern} |
| 91 | default: |
| 92 | return nil |
| 93 | } |
| 94 | } |
| 95 | |
| 96 | func mapKeysSorted(set map[string]struct{}) []string { |
| 97 | out := make([]string, 0, len(set)) |
| 98 | for key := range set { |
| 99 | out = append(out, key) |
| 100 | } |
| 101 | slices.Sort(out) |
| 102 | return out |
| 103 | } |