Created
February 11, 2020 08:01
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| package main | |
| import ( | |
| "bufio" | |
| "os" | |
| "strings" | |
| "fmt" | |
| "time" | |
| "io" | |
| ) | |
| func main() { | |
| if len(os.Args) < 2 { | |
| fmt.Println("file name must be specified.") | |
| return | |
| } | |
| filename := os.Args[1] | |
| file, err := os.Open(filename) | |
| if err != nil { | |
| fmt.Printf("failed to open file: %v", err) | |
| return | |
| } | |
| reader := bufio.NewReader(file) | |
| const layout = "02/Jan/2006:15:04:05 -0700" | |
| dateMap := map[string]uint64{} | |
| for { | |
| b, _, err := reader.ReadLine() | |
| if err == io.EOF { | |
| break | |
| } else if err != nil { | |
| panic(err) | |
| } | |
| line := strings.TrimSpace(string(b)) | |
| if line == "" { | |
| continue | |
| } | |
| d := getDate(line) | |
| dt, err := time.Parse(layout, d) | |
| if err != nil { | |
| fmt.Println(line) | |
| panic(err) | |
| } | |
| date := dt.Format("20060102") | |
| if val, ok := dateMap[date]; ok { | |
| dateMap[date] = val + 1 | |
| } else { | |
| dateMap[date] = 1 | |
| } | |
| } | |
| writers := map[string]*bufio.Writer{} | |
| for date := range dateMap { | |
| fname := date + ".log" | |
| fo, err := os.OpenFile(fname, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644) | |
| if err != nil { | |
| panic(err) | |
| } | |
| defer fo.Close() | |
| fw := bufio.NewWriter(fo) | |
| defer fw.Flush() | |
| writers[date] = fw | |
| } | |
| file.Seek(0, 0) | |
| reader = bufio.NewReader(file) | |
| for { | |
| b, _, err := reader.ReadLine() | |
| if err == io.EOF { | |
| break | |
| } else if err != nil { | |
| panic(err) | |
| } | |
| line := strings.TrimSpace(string(b)) | |
| if line == "" { | |
| continue | |
| } | |
| d := getDate(line) | |
| dt, err := time.Parse(layout, d) | |
| if err != nil { | |
| fmt.Println(line) | |
| panic(err) | |
| } | |
| date := dt.Format("20060102") | |
| if w, ok := writers[date]; ok { | |
| w.WriteString(line) | |
| w.WriteString("\n") | |
| } else { | |
| panic("no writer found") | |
| } | |
| } | |
| } | |
| func getDate(line string) string { | |
| begin := strings.IndexRune(line, '[') | |
| if begin == -1 { | |
| return "" | |
| } | |
| end := strings.IndexRune(line[begin+1:], ']') | |
| if end == -1 { | |
| return "" | |
| } | |
| end++ | |
| return line[begin+1 : begin+end] | |
| } |
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