SE-67: Add ignore-load option

https://jira.percona.com/browse/SE-67

Add `ignore-load` option, which disables any checks of threshold values

README.md

@@ -27,6 +27,7 @@ Here are main commands/flags:
 | any | dump-qan | Process QAN metrics | - |
 | export | start-ts | Start date-time to limit timeframe (in [RFC3339](https://www.ietf.org/rfc/rfc3339.txt) format) | `2006-01-02T15:04:05Z` (please note that you can't use offset for UTC time)<br>`2006-01-02T15:04:05-07:00` |
 | export | end-ts | End date-time to limit timeframe (in [RFC3339](https://www.ietf.org/rfc/rfc3339.txt) format) | `2006-01-02T15:04:05Z` (please note that you can't use offset for UTC time)<br>`2006-01-02T15:04:05-07:00` |
+| export | ignore-load | Disable checking for load values | - |
 | export | max-load | Max value of a metric to postpone export | `CPU=50,RAM=50` |
 | export | critical-load | Max value of a metric to stop export | `CPU=70,RAM=70` |
 | export | stdout | Redirect output to STDOUT | - |

cmd/transferer/main.go

@@ -61,8 +61,9 @@ func main() {
 			"5 minutes by default, example '45s', '5m', '1h'").Default("5m").Duration()
 		chunkRows = exportCmd.Flag("chunk-rows", "Amount of rows to fit into a single chunk (qan metrics)").Default("1000").Int()
 
-		maxLoad = exportCmd.Flag("max-load", "Max load threshold values").
-			Default(fmt.Sprintf("%v=50,%v=50", transferer.ThresholdCPU, transferer.ThresholdRAM)).String()
+		ignoreLoad = exportCmd.Flag("ignore-load", "Disable checking for load threshold values").Bool()
+		maxLoad    = exportCmd.Flag("max-load", "Max load threshold values").
+				Default(fmt.Sprintf("%v=50,%v=50", transferer.ThresholdCPU, transferer.ThresholdRAM)).String()
 		criticalLoad = exportCmd.Flag("critical-load", "Critical load threshold values").
 				Default(fmt.Sprintf("%v=70,%v=70", transferer.ThresholdCPU, transferer.ThresholdRAM)).String()
 
@@ -213,9 +214,12 @@ func main() {
 			log.Fatal().Msgf("Failed to generate chunk pool: %v", err)
 		}
 
-		thresholds, err := transferer.ParseThresholdList(*maxLoad, *criticalLoad)
-		if err != nil {
-			log.Fatal().Err(err).Msgf("Failed to parse max/critical load args")
+		var thresholds []transferer.Threshold
+		if !*ignoreLoad {
+			thresholds, err = transferer.ParseThresholdList(*maxLoad, *criticalLoad)
+			if err != nil {
+				log.Fatal().Err(err).Msgf("Failed to parse max/critical load args")
+			}
 		}
 
 		lc := transferer.NewLoadChecker(ctx, httpC, pmmConfig.VictoriaMetricsURL, thresholds)