race condition in nsq plugin

[phemmer]

Bug report

telegraf/plugins/inputs/nsq/nsq.go

Lines 66 to 76 in c046232

	func (n *NSQ) Gather(acc telegraf.Accumulator) error {
	var wg sync.WaitGroup
	var outerr error
	for _, e := range n.Endpoints {
	wg.Add(1)
	go func(e string) {
	defer wg.Done()
	outerr = n.gatherEndpoint(e, acc)
	}(e)
	}

func (n *NSQ) Gather(acc telegraf.Accumulator) error {
    var wg sync.WaitGroup
    var outerr error

    for _, e := range n.Endpoints {
        wg.Add(1)
        go func(e string) {
            defer wg.Done()
            outerr = n.gatherEndpoint(e, acc)
        }(e)
    }

outerr is not protected via a mutex.
Additionally, whichever call to n.gatherEndpoint completes last wins writing to outerr. Meaning if one server fails, stores the error in outerr, but then the second server completes successfully, the first error is lost.