Adding upstream version 1.34.4.

Signed-off-by: Daniel Baumann <daniel@debian.org>

logger/handler.go

@@ -0,0 +1,142 @@
+package logger
+
+import (
+	"container/list"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/influxdata/telegraf"
+)
+
+type entry struct {
+	timestamp  time.Time
+	level      telegraf.LogLevel
+	prefix     string
+	attributes map[string]interface{}
+	args       []interface{}
+}
+
+type handler struct {
+	level    telegraf.LogLevel
+	timezone *time.Location
+
+	impl      sink
+	earlysink *log.Logger
+	earlylogs *list.List
+	sync.Mutex
+}
+
+func defaultHandler() *handler {
+	return &handler{
+		level:     telegraf.Info,
+		timezone:  time.UTC,
+		earlysink: log.New(os.Stderr, "", 0),
+		earlylogs: list.New(),
+	}
+}
+
+func redirectHandler(w io.Writer) *handler {
+	return &handler{
+		level:     99,
+		timezone:  time.UTC,
+		impl:      &redirectLogger{writer: w},
+		earlysink: log.New(w, "", 0),
+		earlylogs: list.New(),
+	}
+}
+
+func (h *handler) switchSink(impl sink, level telegraf.LogLevel, tz *time.Location, skipEarlyLogs bool) {
+	// Setup the new sink etc
+	h.impl = impl
+	h.level = level
+	h.timezone = tz
+
+	// Use the new logger to output the early log-messages
+	h.Lock()
+	if !skipEarlyLogs && h.earlylogs.Len() > 0 {
+		current := h.earlylogs.Front()
+		for current != nil {
+			e := current.Value.(*entry)
+			h.impl.Print(e.level, e.timestamp.In(h.timezone), e.prefix, e.attributes, e.args...)
+			next := current.Next()
+			h.earlylogs.Remove(current)
+			current = next
+		}
+	}
+	h.Unlock()
+}
+
+func (h *handler) add(level telegraf.LogLevel, ts time.Time, prefix string, attr map[string]interface{}, args ...interface{}) *entry {
+	e := &entry{
+		timestamp:  ts,
+		level:      level,
+		prefix:     prefix,
+		attributes: attr,
+		args:       args,
+	}
+
+	h.Lock()
+	h.earlylogs.PushBack(e)
+	h.Unlock()
+
+	return e
+}
+
+func (h *handler) close() error {
+	if h.impl == nil {
+		return nil
+	}
+
+	h.Lock()
+	current := h.earlylogs.Front()
+	for current != nil {
+		h.earlylogs.Remove(current)
+		current = h.earlylogs.Front()
+	}
+	h.Unlock()
+
+	if l, ok := h.impl.(io.Closer); ok {
+		return l.Close()
+	}
+
+	return nil
+}
+
+// Logger to redirect the logs to an arbitrary writer
+type redirectLogger struct {
+	writer io.Writer
+}
+
+func (l *redirectLogger) Print(level telegraf.LogLevel, ts time.Time, prefix string, attr map[string]interface{}, args ...interface{}) {
+	var attrMsg string
+	if len(attr) > 0 {
+		var parts []string
+		for k, v := range attr {
+			parts = append(parts, fmt.Sprintf("%s=%v", k, v))
+		}
+		attrMsg = "(" + strings.Join(parts, ",") + ")"
+	}
+
+	msg := []interface{}{ts.In(time.UTC).Format(time.RFC3339), level.Indicator()}
+	if prefix+attrMsg != "" {
+		msg = append(msg, prefix+attrMsg)
+	}
+	msg = append(msg, args...)
+
+	fmt.Fprintln(l.writer, msg...)
+}
+
+func (l *redirectLogger) Close() error {
+	if l.writer == os.Stderr {
+		return nil
+	}
+	if closer, ok := l.writer.(io.Closer); ok {
+		return closer.Close()
+	}
+	return nil
+}