x-pack/filebeat/input/awss3 ; Fix nil hit panic when a getter is invoked on input metric

x-pack/filebeat/docs/inputs/input-aws-s3.asciidoc

@@ -797,7 +797,7 @@ observe the activity of the input.
 | `sqs_messages_inflight_gauge`             | Number of SQS messages inflight (gauge).
 | `sqs_messages_returned_total`             | Number of SQS message returned to queue (happens on errors implicitly after visibility timeout passes).
 | `sqs_messages_deleted_total`              | Number of SQS messages deleted.
-| `sqs_messages_waiting_gauge`              | Number of SQS messages waiting in the SQS queue (gauge). The value is refreshed every minute via data from GetQueueAttributes. A value of (0) indicates `no messages waiting` but a value 0f (-1) indicates `metrics not collected/error collecting metrics `
+| `sqs_messages_waiting_gauge`              | Number of SQS messages waiting in the SQS queue (gauge). The value is refreshed every minute via data from https://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_GetQueueAttributes.html<GetQueueAttributes>. A value of `-1` indicates the metric is uninitialized or could not be collected due to an error.
 | `sqs_worker_utilization`                  | Rate of SQS worker utilization over previous 5 seconds. 0 indicates idle, 1 indicates all workers utilized.
 | `sqs_message_processing_time`             | Histogram of the elapsed SQS processing times in nanoseconds (time of receipt to time of delete/return).
 | `sqs_lag_time`                            | Histogram of the difference between the SQS SentTimestamp attribute and the time when the SQS message was received expressed in nanoseconds.

x-pack/filebeat/input/awss3/input.go

@@ -411,6 +411,10 @@ func getProviderFromDomain(endpoint string, ProviderOverride string) string {
 func pollSqsWaitingMetric(ctx context.Context, receiver *sqsReader) {
 	t := time.NewTicker(time.Minute)
 	defer t.Stop()
+	// Initialize the metric to 0 at the start of the one minute time interval to avoid
+	// giving misleading metric value -1 even though SQS messages are processed.
+	// The value will be updated every minute
+	receiver.metrics.sqsMessagesWaiting.Set(int64(0))
 	for {
 		select {
 		case <-ctx.Done():

x-pack/filebeat/input/awss3/sqs.go

@@ -79,9 +79,6 @@ func (r *sqsReader) Receive(ctx context.Context) error {
 		// Process each SQS message asynchronously with a goroutine.
 		r.log.Debugf("Received %v SQS messages.", len(msgs))
 		r.metrics.sqsMessagesReceivedTotal.Add(uint64(len(msgs)))
-		// Initialize the sqs_message_waiting_guage to 0 to indicate that that SQS messages are received.
-		// PollSqsWaitingMetric shall reassign the value if there are messages waiting or if there is an error in processing the messages.
-		r.metrics.sqsMessagesWaiting.Set(int64(0))
 		workerWg.Add(len(msgs))
 
 		for _, msg := range msgs {