fix: break from infinite loop when txn receipt not retrieved

cmd/loadtest/output.go

@@ -105,12 +105,15 @@ func printBlockSummary(c *ethclient.Client, bs map[uint64]blockSummary, startNon
 		p.Printf("Transactions per sec: %v\n", number.Decimal(tps))
 		p.Printf("Gas Per Second: %v\n", number.Decimal(gaspersec))
 		p.Printf("Latencies - Min: %v\tMedian: %v\tMax: %v\n", number.Decimal(minLatency.Seconds()), number.Decimal(medianLatency.Seconds()), number.Decimal(maxLatency.Seconds()))
-		p.Printf("Mean Blocktime: %vs\n", number.Decimal(meanBlocktime))
-		p.Printf("Median Blocktime: %vs\n", number.Decimal(medianBlocktime))
-		p.Printf("Minimum Blocktime: %vs\n", number.Decimal(minBlocktime))
-		p.Printf("Maximum Blocktime: %vs\n", number.Decimal(maxBlocktime))
-		p.Printf("Blocktime Standard Deviation: %vs\n", number.Decimal(stddevBlocktime))
-		p.Printf("Blocktime Variance: %vs\n", number.Decimal(varianceBlocktime))
+		// Blocktime related metrics can only be calculated when there are at least two blocks
+		if len(bs) > 1 {
+			p.Printf("Mean Blocktime: %vs\n", number.Decimal(meanBlocktime))
+			p.Printf("Median Blocktime: %vs\n", number.Decimal(medianBlocktime))
+			p.Printf("Minimum Blocktime: %vs\n", number.Decimal(minBlocktime))
+			p.Printf("Maximum Blocktime: %vs\n", number.Decimal(maxBlocktime))
+			p.Printf("Blocktime Standard Deviation: %vs\n", number.Decimal(stddevBlocktime))
+			p.Printf("Blocktime Variance: %vs\n", number.Decimal(varianceBlocktime))
+		}
 	} else if summaryOutputMode == "json" {
 		summaryOutput := SummaryOutput{}
 		summaryOutput.Summaries = jsonSummaryList

util/util.go

@@ -161,14 +161,36 @@ func GetReceipts(ctx context.Context, rawBlocks []*json.RawMessage, c *ethrpc.Cl
 			}
 			break
 		}
-
-		err := c.BatchCallContext(ctx, blms[start:end])
-		if err != nil {
-			log.Error().Err(err).Str("randtx", txHashes[0]).Uint64("start", start).Uint64("end", end).Msg("RPC issue fetching receipts")
-			return nil, err
-		}
-		start = end
-		if last {
+		// go-ethereum's BatchCallContext fails when the number of txns are over 100, because it attempts to unmarshal a single json source object into a slice if the number of txns go over 100.
+		// A workaround could be to implement our own unmarshal function for batch calls to unmarshal the single json object into a custom type (non-slice), but the below method has been chosen.
+		// When the number of txns go over 100 and forms a slice, this logic will batch call in units of 100 txns. This will successfully unmarshal the json source object.
+		if end <= 100 {
+			err := c.BatchCallContext(ctx, blms[start:end])
+			if err != nil {
+				log.Error().Err(err).Str("randtx", txHashes[0]).Uint64("start", start).Uint64("end", end).Msg("RPC issue fetching receipts")
+				break
+			}
+			start = end
+			if last {
+				break
+			}
+		} else {
+			for index := uint64(0); index <= end; index = index + 100 {
+				// Check for the final section of the slice, and also check end is not equal to index, because this will send another already sent BatchCall otherwise.
+				if end < index+100 && end != index {
+					err := c.BatchCallContext(ctx, blms[index:end])
+					if err != nil {
+						log.Error().Err(err).Str("randtx", txHashes[0]).Uint64("start", start).Uint64("end", end).Msg("RPC issue fetching receipts")
+						break
+					}
+					break
+				}
+				err := c.BatchCallContext(ctx, blms[index:index+100])
+				if err != nil {
+					log.Error().Err(err).Str("randtx", txHashes[0]).Uint64("start", start).Uint64("end", end).Msg("RPC issue fetching receipts")
+					break
+				}
+			}
 			break
 		}
 	}
@@ -182,6 +204,10 @@ func GetReceipts(ctx context.Context, rawBlocks []*json.RawMessage, c *ethrpc.Cl
 		}
 		receipts = append(receipts, b.Result.(*json.RawMessage))
 	}
+	if len(receipts) == 0 {
+		log.Error().Msg("No receipts have been fetched")
+		return nil, nil
+	}
 	log.Info().Int("hashes", len(txHashes)).Int("receipts", len(receipts)).Msg("Fetched tx receipts")
 	return receipts, nil
 }