Add Start() function to DockerLogs input plugin (#6157)

plugins/inputs/docker_log/docker_log.go

@@ -68,6 +68,8 @@ const (
 
 var (
 	containerStates = []string{"created", "restarting", "running", "removing", "paused", "exited", "dead"}
+	// ensure *DockerLogs implements telegaf.ServiceInput
+	_ telegraf.ServiceInput = (*DockerLogs)(nil)
 )
 
 type DockerLogs struct {
@@ -380,6 +382,12 @@ func tailMultiplexed(
 	return err
 }
 
+// Start is a noop which is required for a *DockerLogs to implement
+// the telegraf.ServiceInput interface
+func (d *DockerLogs) Start(telegraf.Accumulator) error {
+	return nil
+}
+
 func (d *DockerLogs) Stop() {
 	d.cancelTails()
 	d.wg.Wait()