| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | package logs |
| 4 | |
| 5 | import ( |
| 6 | "bufio" |
| 7 | "errors" |
| 8 | "fmt" |
| 9 | "io" |
| 10 | "regexp" |
| 11 | "slices" |
| 12 | ) |
| 13 | |
| 14 | type ( |
| 15 | RegExpConfig struct { |
| 16 | Pattern string `yaml:"pattern" json:"pattern"` |
| 17 | } |
| 18 | |
| 19 | RegExpParser struct { |
| 20 | r *bufio.Reader |
| 21 | pattern *regexp.Regexp |
| 22 | } |
| 23 | ) |
| 24 | |
| 25 | func NewRegExpParser(config RegExpConfig, in io.Reader) (*RegExpParser, error) { |
| 26 | if config.Pattern == "" { |
| 27 | return nil, errors.New("empty pattern") |
| 28 | } |
| 29 | |
| 30 | pattern, err := regexp.Compile(config.Pattern) |
| 31 | if err != nil { |
| 32 | return nil, fmt.Errorf("compile: %w", err) |
| 33 | } |
| 34 | |
| 35 | if hasNamed := slices.ContainsFunc(pattern.SubexpNames(), func(s string) bool { return s != "" }); !hasNamed { |
| 36 | return nil, errors.New("pattern has no named subgroups") |
| 37 | } |
| 38 | |
| 39 | p := &RegExpParser{ |
| 40 | r: bufio.NewReader(in), |
| 41 | pattern: pattern, |
| 42 | } |
| 43 | return p, nil |
| 44 | } |
| 45 | |
| 46 | func (p *RegExpParser) ReadLine(line LogLine) error { |
| 47 | row, err := p.r.ReadSlice('\n') |
| 48 | if err != nil && len(row) == 0 { |
| 49 | return err |
| 50 | } |
| 51 | if len(row) > 0 && row[len(row)-1] == '\n' { |
| 52 | row = row[:len(row)-1] |
| 53 | } |
| 54 | return p.Parse(row, line) |
| 55 | } |
| 56 | |
| 57 | func (p *RegExpParser) Parse(row []byte, line LogLine) error { |
| 58 | match := p.pattern.FindSubmatch(row) |
| 59 | if len(match) == 0 { |
| 60 | return &ParseError{msg: "regexp parse: unmatched line"} |
| 61 | } |
| 62 | |
| 63 | for i, name := range p.pattern.SubexpNames() { |
| 64 | if name == "" || match[i] == nil { |
| 65 | continue |
| 66 | } |
| 67 | err := line.Assign(name, string(match[i])) |
| 68 | if err != nil { |
| 69 | return &ParseError{msg: fmt.Sprintf("regexp parse: %v", err), err: err} |
| 70 | } |
| 71 | } |
| 72 | return nil |
| 73 | } |
| 74 | |
| 75 | func (p RegExpParser) Info() string { |
| 76 | return fmt.Sprintf("regexp: %s", p.pattern) |
| 77 | } |