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Synchronize the cursor returned by followJournal

Make sure that the cursor value returned by followJournal() is the last
of the values returned by its goroutine's calls to drainJournal() by
waiting for it, rather than returning a value that may be superceded by
another if we're singalling the goroutine that it should exit by closing
a pipe.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>
(cherry picked from commit d57c330617)
Signed-off-by: Victor Vieux <victorvieux@gmail.com>
This commit is contained in:
Nalin Dahyabhai 2017-02-22 16:22:00 -05:00 committed by Victor Vieux
parent 52a7b8350a
commit 4730409857

View file

@ -248,6 +248,9 @@ func (s *journald) followJournal(logWatcher *logger.LogWatcher, config logger.Re
s.readers.mu.Lock()
s.readers.readers[logWatcher] = logWatcher
s.readers.mu.Unlock()
newCursor := make(chan *C.char)
go func() {
// Keep copying journal data out until we're notified to stop
// or we hit an error.
@ -268,6 +271,7 @@ func (s *journald) followJournal(logWatcher *logger.LogWatcher, config logger.Re
delete(s.readers.readers, logWatcher)
s.readers.mu.Unlock()
close(logWatcher.Msg)
newCursor <- cursor
}()
// Wait until we're told to stop.
select {
@ -276,6 +280,8 @@ func (s *journald) followJournal(logWatcher *logger.LogWatcher, config logger.Re
C.close(pfd[1])
}
cursor = <-newCursor
return cursor
}