feat(storage): Specify benchmark integrity check. (googleapis#11465)

Allow the benchmark runner to specify the integrity check mode to use
for uploads.

Author: cjc25

storage/internal/benchmarks/benchmark_result.go

@@ -87,7 +87,15 @@ func (br *benchmarkResult) selectWriteParams(opts benchmarkOptions, api benchmar
 		api = jsonAPI
 	}
 
-	_, doMD5, doCRC32C := randomOf3()
+	doMD5, doCRC32C := false, false
+	switch opts.integrity {
+	case crc32cIC:
+		doCRC32C = true
+	case md5IC:
+		doMD5 = true
+	case randomIC:
+		_, doMD5, doCRC32C = randomOf3()
+	}
 	br.params = randomizedParams{
 		appBufferSize: opts.writeBufferSize,
 		chunkSize:     randomInt64(opts.minChunkSize, opts.maxChunkSize),

storage/internal/benchmarks/main.go

@@ -66,6 +66,7 @@ type benchmarkOptions struct {
 	numSamples int
 	numWorkers int
 	api        benchmarkAPI
+	integrity  benchmarkIC
 
 	objectSize    int64
 	minObjectSize int64
@@ -130,6 +131,7 @@ func (b *benchmarkOptions) String() string {
 
 	stringifiedOpts := []string{
 		fmt.Sprintf("api:\t\t\t%s", b.api),
+		fmt.Sprintf("interity check:\t\t%d", b.integrity),
 		fmt.Sprintf("region:\t\t\t%s", b.region),
 		fmt.Sprintf("timeout:\t\t%s", b.timeout),
 		fmt.Sprintf("number of samples:\t%d", b.numSamples),
@@ -163,6 +165,7 @@ func parseFlags() {
 	flag.IntVar(&opts.numSamples, "samples", 8000, "number of samples to report")
 	flag.IntVar(&opts.numWorkers, "workers", 16, "number of concurrent workers")
 	flag.StringVar((*string)(&opts.api), "api", string(mixedAPIs), "api used to upload/download objects; JSON or XML values will use JSON to uplaod and XML to download")
+	flag.StringVar((*string)(&opts.integrity), "integrity", string(randomIC), "integrity check performed on uploads; crc32c, md5, none, or random (default) to randomly choose which to check on each upload")
 
 	objectRange := flag.String("object_size", fmt.Sprint(1024*kib), "object size in bytes")
 
@@ -329,6 +332,15 @@ const (
 	directPath benchmarkAPI = "DirectPath"
 )
 
+type benchmarkIC string
+
+const (
+	crc32cIC benchmarkIC = "crc32c"
+	md5IC    benchmarkIC = "md5"
+	noneIC   benchmarkIC = "none"
+	randomIC benchmarkIC = "random"
+)
+
 func (api benchmarkAPI) validate() error {
 	switch api {
 	case jsonAPI, grpcAPI, xmlAPI, directPath, mixedAPIs: