diff --git a/libpod/events/journal_linux.go b/libpod/events/journal_linux.go index 16ef6504f2..4986502a27 100644 --- a/libpod/events/journal_linux.go +++ b/libpod/events/journal_linux.go @@ -112,57 +112,16 @@ func (e EventJournalD) Read(ctx context.Context, options ReadOptions) error { } } - // the api requires a next|prev before getting a cursor - if _, err := j.Next(); err != nil { - return fmt.Errorf("failed to move journal cursor to next entry: %w", err) - } - - prevCursor, err := j.GetCursor() - if err != nil { - return fmt.Errorf("failed to get journal cursor: %w", err) - } for { - select { - case <-ctx.Done(): - // the consumer has cancelled - return nil - default: - // fallthrough - } - - if _, err := j.Next(); err != nil { - return fmt.Errorf("failed to move journal cursor to next entry: %w", err) - } - newCursor, err := j.GetCursor() + entry, err := getNextEntry(ctx, j, options.Stream, untilTime) if err != nil { - return fmt.Errorf("failed to get journal cursor: %w", err) + return err } - if prevCursor == newCursor { - if !options.Stream || (len(options.Until) > 0 && time.Now().After(untilTime)) { - break - } - - // j.Wait() is blocking, this would cause the goroutine to hang forever - // if no more journal entries are generated and thus if the client - // has closed the connection in the meantime to leak memory. - // Waiting only 5 seconds makes sure we can check if the client closed in the - // meantime at least every 5 seconds. - t := 5 * time.Second - if len(options.Until) > 0 { - until := time.Until(untilTime) - if until < t { - t = until - } - } - _ = j.Wait(t) - continue + // no entry == we hit the end + if entry == nil { + return nil } - prevCursor = newCursor - entry, err := j.GetEntry() - if err != nil { - return fmt.Errorf("failed to read journal entry: %w", err) - } newEvent, err := newEventFromJournalEntry(entry) if err != nil { // We can't decode this event. @@ -177,7 +136,6 @@ func (e EventJournalD) Read(ctx context.Context, options ReadOptions) error { options.EventChannel <- newEvent } } - return nil } func newEventFromJournalEntry(entry *sdjournal.JournalEntry) (*Event, error) { @@ -238,3 +196,51 @@ func newEventFromJournalEntry(entry *sdjournal.JournalEntry) (*Event, error) { func (e EventJournalD) String() string { return Journald.String() } + +// getNextEntry returns the next entry in the journal. If the end of the +// journal is reached and stream is not set or the current time is after +// the until time this function return nil,nil. +func getNextEntry(ctx context.Context, j *sdjournal.Journal, stream bool, untilTime time.Time) (*sdjournal.JournalEntry, error) { + for { + select { + case <-ctx.Done(): + // the consumer has cancelled + return nil, nil + default: + // fallthrough + } + // the api requires a next|prev before reading the event + ret, err := j.Next() + if err != nil { + return nil, fmt.Errorf("failed to move journal cursor to next entry: %w", err) + } + // ret == 0 equals EOF, see sd_journal_next(3) + if ret == 0 { + if !stream || (!untilTime.IsZero() && time.Now().After(untilTime)) { + // we hit the end and should not keep streaming + return nil, nil + } + // keep waiting for the next entry + // j.Wait() is blocking, this would cause the goroutine to hang forever + // if no more journal entries are generated and thus if the client + // has closed the connection in the meantime to leak memory. + // Waiting only 5 seconds makes sure we can check if the client closed in the + // meantime at least every 5 seconds. + t := 5 * time.Second + if !untilTime.IsZero() { + until := time.Until(untilTime) + if until < t { + t = until + } + } + _ = j.Wait(t) + continue + } + + entry, err := j.GetEntry() + if err != nil { + return nil, fmt.Errorf("failed to read journal entry: %w", err) + } + return entry, nil + } +}