| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | package matcher |
| 4 | |
| 5 | import ( |
| 6 | "errors" |
| 7 | "fmt" |
| 8 | "regexp" |
| 9 | ) |
| 10 | |
| 11 | type ( |
| 12 | // Matcher is an interface that wraps MatchString method. |
| 13 | Matcher interface { |
| 14 | // Match performs match against given []byte |
| 15 | Match(b []byte) bool |
| 16 | // MatchString performs match against given string |
| 17 | MatchString(string) bool |
| 18 | } |
| 19 | |
| 20 | // Format matcher format |
| 21 | Format string |
| 22 | ) |
| 23 | |
| 24 | const ( |
| 25 | // FmtString is a string match format. |
| 26 | FmtString Format = "string" |
| 27 | // FmtGlob is a glob match format. |
| 28 | FmtGlob Format = "glob" |
| 29 | // FmtRegExp is a regex match format. |
| 30 | FmtRegExp Format = "regexp" |
| 31 | // FmtSimplePattern is a simple pattern match format |
| 32 | // https://docs.netdata.cloud/libnetdata/simple_pattern/ |
| 33 | FmtSimplePattern Format = "simple_patterns" |
| 34 | |
| 35 | // Separator is a separator between match format and expression. |
| 36 | Separator = ":" |
| 37 | ) |
| 38 | |
| 39 | const ( |
| 40 | symString = "=" |
| 41 | symGlob = "*" |
| 42 | symRegExp = "~" |
| 43 | ) |
| 44 | |
| 45 | var ( |
| 46 | reShortSyntax = regexp.MustCompile(`(?s)^(!)?(.)\s*(.*)$`) |
| 47 | reLongSyntax = regexp.MustCompile(`(?s)^(!)?([^:]+):(.*)$`) |
| 48 | |
| 49 | errNotShortSyntax = errors.New("not short syntax") |
| 50 | ) |
| 51 | |
| 52 | // Must is a helper that wraps a call to a function returning (Matcher, error) and panics if the error is non-nil. |
| 53 | // It is intended for use in variable initializations such as |
| 54 | // |
| 55 | // var m = matcher.Must(matcher.New(matcher.FmtString, "hello world")) |
| 56 | func Must(m Matcher, err error) Matcher { |
| 57 | if err != nil { |
| 58 | panic(err) |
| 59 | } |
| 60 | return m |
| 61 | } |
| 62 | |
| 63 | // New create a matcher |
| 64 | func New(format Format, expr string) (Matcher, error) { |
| 65 | switch format { |
| 66 | case FmtString: |
| 67 | return NewStringMatcher(expr, true, true) |
| 68 | case FmtGlob: |
| 69 | return NewGlobMatcher(expr) |
| 70 | case FmtRegExp: |
| 71 | return NewRegExpMatcher(expr) |
| 72 | case FmtSimplePattern: |
| 73 | return NewSimplePatternsMatcher(expr) |
| 74 | default: |
| 75 | return nil, fmt.Errorf("unsupported matcher format: '%s'", format) |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | // Parse parses line and returns appropriate matcher based on matched format. |
| 80 | // |
| 81 | // Short Syntax |
| 82 | // |
| 83 | // <line> ::= [ <not> ] <format> <space> <expr> |
| 84 | // <not> ::= '!' |
| 85 | // negative expression |
| 86 | // <format> ::= [ '=', '~', '*' ] |
| 87 | // '=' means string match |
| 88 | // '~' means regexp match |
| 89 | // '*' means glob match |
| 90 | // <space> ::= { ' ' | '\t' | '\n' | '\n' | '\r' } |
| 91 | // <expr> ::= any string |
| 92 | // |
| 93 | // Long Syntax |
| 94 | // |
| 95 | // <line> ::= [ <not> ] <format> <separator> <expr> |
| 96 | // <format> ::= [ 'string' | 'glob' | 'regexp' | 'simple_patterns' ] |
| 97 | // <not> ::= '!' |
| 98 | // negative expression |
| 99 | // <separator> ::= ':' |
| 100 | // <expr> ::= any string |
| 101 | func Parse(line string) (Matcher, error) { |
| 102 | matcher, err := parseShortFormat(line) |
| 103 | if err == nil { |
| 104 | return matcher, nil |
| 105 | } |
| 106 | return parseLongSyntax(line) |
| 107 | } |
| 108 | |
| 109 | func parseShortFormat(line string) (Matcher, error) { |
| 110 | m := reShortSyntax.FindStringSubmatch(line) |
| 111 | if m == nil { |
| 112 | return nil, errNotShortSyntax |
| 113 | } |
| 114 | var format Format |
| 115 | switch m[2] { |
| 116 | case symString: |
| 117 | format = FmtString |
| 118 | case symGlob: |
| 119 | format = FmtGlob |
| 120 | case symRegExp: |
| 121 | format = FmtRegExp |
| 122 | default: |
| 123 | return nil, fmt.Errorf("invalid short syntax: unknown symbol '%s'", m[2]) |
| 124 | } |
| 125 | expr := m[3] |
| 126 | matcher, err := New(format, expr) |
| 127 | if err != nil { |
| 128 | return nil, err |
| 129 | } |
| 130 | if m[1] != "" { |
| 131 | matcher = Not(matcher) |
| 132 | } |
| 133 | return matcher, nil |
| 134 | } |
| 135 | |
| 136 | func parseLongSyntax(line string) (Matcher, error) { |
| 137 | m := reLongSyntax.FindStringSubmatch(line) |
| 138 | if m == nil { |
| 139 | return nil, fmt.Errorf("invalid syntax") |
| 140 | } |
| 141 | matcher, err := New(Format(m[2]), m[3]) |
| 142 | if err != nil { |
| 143 | return nil, err |
| 144 | } |
| 145 | if m[1] != "" { |
| 146 | matcher = Not(matcher) |
| 147 | } |
| 148 | return matcher, nil |
| 149 | } |