add --metadata and --tag during put operations

cli/flags.go

@@ -269,6 +269,16 @@ var ioFlags = []cli.Flag{
 		Value: 0,
 		Usage: "Rate limit each instance to this number of requests per second (0 to disable)",
 	},
+	cli.StringSliceFlag{
+		Name:  "metadata",
+		Usage: "Add user metada to all objects using the format <key>=<value>. Random value can be set with 'rand:%length'. Can be used multiple times. Example: --metadata foo=bar --metadata randomValue=rand:1024.",
+		Hidden: true,
+	},
+	cli.StringSliceFlag{
+		Name:  "tag",
+		Usage: "Add user tag to all objects using the format <key>=<value>. Random value can be set with 'rand:%length'. Can be used multiple times. Example: --tag foo=bar --tag randomValue=rand:1024.",
+		Hidden: true,
+	},
 }
 
 func getCommon(ctx *cli.Context, src func() generator.Source) bench.Common {

cli/put.go

@@ -18,6 +18,9 @@
 package cli
 
 import (
+	"fmt"
+	"math/rand"
+	"strings"
 	"github.com/minio/cli"
 	"github.com/minio/minio-go/v7"
 	"github.com/minio/pkg/v2/console"
@@ -71,17 +74,53 @@ func mainPut(ctx *cli.Context) error {
 	return runBench(ctx, &b)
 }
 
+const metadataChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890-_."
+
 // putOpts retrieves put options from the context.
 func putOpts(ctx *cli.Context) minio.PutObjectOptions {
 	pSize, _ := toSize(ctx.String("part.size"))
-	return minio.PutObjectOptions{
+	options := minio.PutObjectOptions{
 		ServerSideEncryption: newSSE(ctx),
 		DisableMultipart:     ctx.Bool("disable-multipart"),
 		DisableContentSha256: ctx.Bool("disable-sha256-payload"),
 		SendContentMd5:       ctx.Bool("md5"),
 		StorageClass:         ctx.String("storage-class"),
 		PartSize:             pSize,
 	}
+
+	for _, flag := range []string{"metadata", "tag"} {
+		values := make(map[string]string)
+
+		for _, v := range ctx.StringSlice(flag) {
+				idx := strings.Index(v, "=")
+				if idx <= 0 {
+					console.Fatalf("--%s takes `key=value` argument", flag)
+				}
+				key := v[:idx]
+				value := v[idx+1:]
+				if len(value) == 0 {
+					console.Fatal("--%s value can't be empty", flag)
+				}
+				var rand_n int;
+				if _, err := fmt.Sscanf(value, "rand:%d", &rand_n); err == nil {
+					rng := rand.New(rand.NewSource(int64(rand.Uint64())))
+					value = ""
+					for i:=0; i<rand_n; i++ {
+						value = value + string(metadataChars[rng.Int()%len(metadataChars)])
+					}
+				}
+				values[key] = value
+		}
+
+		switch flag {
+			case "metadata":
+				options.UserMetadata = values
+			case "tag":
+				options.UserTags = values
+		}
+	}
+
+	return options
 }
 
 func checkPutSyntax(ctx *cli.Context) {