Initial commit

vendor/github.com/hyperhq/hypercli/daemon/logger/logger.go

@@ -0,0 +1,87 @@
+// Package logger defines interfaces that logger drivers implement to
+// log messages.
+//
+// The other half of a logger driver is the implementation of the
+// factory, which holds the contextual instance information that
+// allows multiple loggers of the same type to perform different
+// actions, such as logging to different locations.
+package logger
+
+import (
+	"errors"
+	"time"
+
+	"github.com/hyperhq/hypercli/pkg/jsonlog"
+)
+
+// ErrReadLogsNotSupported is returned when the logger does not support reading logs.
+var ErrReadLogsNotSupported = errors.New("configured logging reader does not support reading")
+
+const (
+	// TimeFormat is the time format used for timestamps sent to log readers.
+	TimeFormat           = jsonlog.RFC3339NanoFixed
+	logWatcherBufferSize = 4096
+)
+
+// Message is datastructure that represents record from some container.
+type Message struct {
+	ContainerID string
+	Line        []byte
+	Source      string
+	Timestamp   time.Time
+}
+
+// Logger is the interface for docker logging drivers.
+type Logger interface {
+	Log(*Message) error
+	Name() string
+	Close() error
+}
+
+// ReadConfig is the configuration passed into ReadLogs.
+type ReadConfig struct {
+	Since  time.Time
+	Tail   int
+	Follow bool
+}
+
+// LogReader is the interface for reading log messages for loggers that support reading.
+type LogReader interface {
+	// Read logs from underlying logging backend
+	ReadLogs(ReadConfig) *LogWatcher
+}
+
+// LogWatcher is used when consuming logs read from the LogReader interface.
+type LogWatcher struct {
+	// For sending log messages to a reader.
+	Msg chan *Message
+	// For sending error messages that occur while while reading logs.
+	Err           chan error
+	closeNotifier chan struct{}
+}
+
+// NewLogWatcher returns a new LogWatcher.
+func NewLogWatcher() *LogWatcher {
+	return &LogWatcher{
+		Msg:           make(chan *Message, logWatcherBufferSize),
+		Err:           make(chan error, 1),
+		closeNotifier: make(chan struct{}),
+	}
+}
+
+// Close notifies the underlying log reader to stop.
+func (w *LogWatcher) Close() {
+	// only close if not already closed
+	select {
+	case <-w.closeNotifier:
+	default:
+		close(w.closeNotifier)
+	}
+}
+
+// WatchClose returns a channel receiver that receives notification
+// when the watcher has been closed. This should only be called from
+// one goroutine.
+func (w *LogWatcher) WatchClose() <-chan struct{} {
+	return w.closeNotifier
+}