plugin/trace: make zipkin and datadog reporters log errors using CoreDNS logger (#5452)

plugin/trace/logger.go

@@ -0,0 +1,20 @@
+package trace
+
+import (
+	clog "github.com/coredns/coredns/plugin/pkg/log"
+)
+
+// loggerAdapter is a simple adapter around plugin logger made to implement io.Writer and ddtrace.Logger interface
+// in order to log errors from span reporters as warnings
+type loggerAdapter struct {
+	clog.P
+}
+
+func (l *loggerAdapter) Write(p []byte) (n int, err error) {
+	l.P.Warning(string(p))
+	return len(p), nil
+}
+
+func (l *loggerAdapter) Log(msg string) {
+	l.P.Warning(msg)
+}