mirror of https://github.com/nealey/spongy
88 lines
1.4 KiB
Go
88 lines
1.4 KiB
Go
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package logfile
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import (
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"fmt"
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"os"
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"time"
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)
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type Logfile struct {
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file *os.File
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name string
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nlines int
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maxlines int
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}
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func NewLogfile(maxlines int) (*Logfile) {
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return &Logfile{nil, "", 0, maxlines}
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}
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func (lf *Logfile) Close() {
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if lf.file != nil {
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lf.writeln("EXIT")
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lf.file.Close()
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}
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}
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func (lf *Logfile) writeln(s string) error {
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_, err := fmt.Fprintf(lf.file, "%d %s\n", time.Now().Unix(), s)
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if err == nil {
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lf.nlines += 1
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}
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return err
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}
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func (lf *Logfile) rotate() error {
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fn := fmt.Sprintf("%s.log", time.Now().UTC().Format(time.RFC3339))
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newf, err := os.OpenFile(fn, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0666)
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if err != nil {
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return err
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}
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if lf.file == nil {
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// Set lf.file just so we can write out NEXTLOG.
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// If this fails, that's okay
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lf.file, _ = os.OpenFile("current", os.O_WRONLY|os.O_APPEND, 0666)
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}
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if lf.file != nil {
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// Note location of new log
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logmsg := fmt.Sprintf(". NEXTLOG %s", fn)
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lf.writeln(logmsg)
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// All done with the current log
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lf.file.Close()
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}
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// Point to new log file
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lf.file = newf
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// Record symlink to new log
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os.Remove("current")
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os.Symlink(fn, "current")
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logmsg := fmt.Sprintf(". PREVLOG %s", lf.name)
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lf.writeln(logmsg)
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lf.name = fn
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return nil
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}
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func (lf *Logfile) Log(s string) error {
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if lf.file == nil {
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lf.rotate()
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}
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err := lf.writeln(s)
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if err == nil {
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return err
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}
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if lf.nlines >= lf.maxlines {
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return lf.rotate()
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}
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return nil
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}
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