feat: implements tagging support for CreateBucket

Closes #1595

This implementation diverges from AWS S3 behavior. The `CreateBucket` request body is no longer ignored. Based on the S3 request body schema, the gateway parses only the `LocationConstraint` and `Tags` fields. If the `LocationConstraint` does not match the gateway’s region, it returns an `InvalidLocationConstraint` error.

In AWS S3, tagging during bucket creation is supported only for directory buckets. The gateway extends this support to general-purpose buckets.

If the request body is malformed, the gateway returns a `MalformedXML` error.

s3api/controllers/bucket-put.go

@@ -533,6 +533,32 @@ func (c S3ApiController) CreateBucket(ctx *fiber.Ctx) (*Response, error) {
 		}, s3err.GetAPIError(s3err.ErrBothCannedAndHeaderGrants)
 	}
 
+	var body s3response.CreateBucketConfiguration
+	if len(ctx.Body()) != 0 {
+		// request body is optional for CreateBucket
+		err := xml.Unmarshal(ctx.Body(), &body)
+		if err != nil {
+			debuglogger.Logf("failed to parse the request body: %v", err)
+			return &Response{
+				MetaOpts: &MetaOptions{
+					BucketOwner: acct.Access,
+				},
+			}, s3err.GetAPIError(s3err.ErrMalformedXML)
+		}
+
+		if body.LocationConstraint != "" {
+			region := utils.ContextKeyRegion.Get(ctx).(string)
+			if body.LocationConstraint != region {
+				debuglogger.Logf("invalid location constraint: %s", body.LocationConstraint)
+				return &Response{
+					MetaOpts: &MetaOptions{
+						BucketOwner: acct.Access,
+					},
+				}, s3err.GetAPIError(s3err.ErrInvalidLocationConstraint)
+			}
+		}
+	}
+
 	defACL := auth.ACL{
 		Owner: acct.Access,
 	}
@@ -562,6 +588,9 @@ func (c S3ApiController) CreateBucket(ctx *fiber.Ctx) (*Response, error) {
 		Bucket:                     &bucket,
 		ObjectOwnership:            objectOwnership,
 		ObjectLockEnabledForBucket: &lockEnabled,
+		CreateBucketConfiguration: &types.CreateBucketConfiguration{
+			Tags: body.TagSet,
+		},
 	}, updAcl)
 	return &Response{
 		MetaOpts: &MetaOptions{

s3api/controllers/bucket-put_test.go

@@ -695,6 +695,11 @@ func TestS3ApiController_CreateBucket(t *testing.T) {
 		Role:   auth.RoleUser,
 	}
 
+	invLocConstBody, err := xml.Marshal(s3response.CreateBucketConfiguration{
+		LocationConstraint: "us-west-1",
+	})
+	assert.NoError(t, err)
+
 	tests := []struct {
 		name   string
 		input  testInput
@@ -729,6 +734,37 @@ func TestS3ApiController_CreateBucket(t *testing.T) {
 				err: s3err.GetAPIError(s3err.ErrInvalidBucketName),
 			},
 		},
+		{
+			name: "malformed body",
+			input: testInput{
+				locals: map[utils.ContextKey]any{
+					utils.ContextKeyAccount: adminAcc,
+				},
+				body: []byte("invalid_body"),
+			},
+			output: testOutput{
+				response: &Response{
+					MetaOpts: &MetaOptions{BucketOwner: adminAcc.Access},
+				},
+				err: s3err.GetAPIError(s3err.ErrMalformedXML),
+			},
+		},
+		{
+			name: "invalid location constraint",
+			input: testInput{
+				locals: map[utils.ContextKey]any{
+					utils.ContextKeyAccount: adminAcc,
+					utils.ContextKeyRegion:  "us-east-1",
+				},
+				body: invLocConstBody,
+			},
+			output: testOutput{
+				response: &Response{
+					MetaOpts: &MetaOptions{BucketOwner: adminAcc.Access},
+				},
+				err: s3err.GetAPIError(s3err.ErrInvalidLocationConstraint),
+			},
+		},
 		{
 			name: "invalid ownership",
 			input: testInput{