Add num scrapes as tsdb write benchmark command flag

By default same value that was hardcoded is used, but with the
new flag added the number of scrapes can be increased to any value.

Signed-off-by: Pau Freixes <pfreixes@gmail.com>

cmd/promtool/main.go

@@ -124,6 +124,7 @@ func main() {
 	tsdbBenchWriteCmd := tsdbBenchCmd.Command("write", "Run a write performance benchmark.")
 	benchWriteOutPath := tsdbBenchWriteCmd.Flag("out", "Set the output path.").Default("benchout").String()
 	benchWriteNumMetrics := tsdbBenchWriteCmd.Flag("metrics", "Number of metrics to read.").Default("10000").Int()
+	benchWriteNumScrapes := tsdbBenchWriteCmd.Flag("scrapes", "Number of scrapes to simulate.").Default("3000").Int()
 	benchSamplesFile := tsdbBenchWriteCmd.Arg("file", "Input file with samples data, default is ("+filepath.Join("..", "..", "tsdb", "testdata", "20kseries.json")+").").Default(filepath.Join("..", "..", "tsdb", "testdata", "20kseries.json")).String()
 
 	tsdbAnalyzeCmd := tsdbCmd.Command("analyze", "Analyze churn, label pair cardinality.")
@@ -195,7 +196,7 @@ func main() {
 		os.Exit(RulesUnitTest(*testRulesFiles...))
 
 	case tsdbBenchWriteCmd.FullCommand():
-		os.Exit(checkErr(benchmarkWrite(*benchWriteOutPath, *benchSamplesFile, *benchWriteNumMetrics)))
+		os.Exit(checkErr(benchmarkWrite(*benchWriteOutPath, *benchSamplesFile, *benchWriteNumMetrics, *benchWriteNumScrapes)))
 
 	case tsdbAnalyzeCmd.FullCommand():
 		os.Exit(checkErr(analyzeBlock(*analyzePath, *analyzeBlockID, *analyzeLimit)))

cmd/promtool/tsdb.go

@@ -58,7 +58,7 @@ type writeBenchmark struct {
 	logger    log.Logger
 }
 
-func benchmarkWrite(outPath, samplesFile string, numMetrics int) error {
+func benchmarkWrite(outPath, samplesFile string, numMetrics, numScrapes int) error {
 	b := &writeBenchmark{
 		outPath:     outPath,
 		samplesFile: samplesFile,
@@ -118,7 +118,7 @@ func benchmarkWrite(outPath, samplesFile string, numMetrics int) error {
 		if err := b.startProfiling(); err != nil {
 			return err
 		}
-		total, err = b.ingestScrapes(lbs, 3000)
+		total, err = b.ingestScrapes(lbs, numScrapes)
 		if err != nil {
 			return err
 		}