fix(backend): Refactor S3 bucket management by replacing MinIO client code with AWS SDK v2 and improving configuration validation

backend/src/apiserver/client_manager/client_manager.go

@@ -17,6 +17,7 @@ package clientmanager
 import (
 	"context"
 	"database/sql"
+	"errors"
 	"fmt"
 	"strings"
 	"sync"
@@ -26,6 +27,8 @@ import (
 	awsv2cfg "github.com/aws/aws-sdk-go-v2/config"
 	awsv2creds "github.com/aws/aws-sdk-go-v2/credentials"
 	"github.com/aws/aws-sdk-go-v2/service/s3"
+	s3types "github.com/aws/aws-sdk-go-v2/service/s3/types"
+	"github.com/aws/smithy-go"
 	"github.com/cenkalti/backoff"
 	mysqlStd "github.com/go-sql-driver/mysql"
 	"github.com/golang/glog"
@@ -38,8 +41,6 @@ import (
 	"github.com/kubeflow/pipelines/backend/src/apiserver/validation"
 	"github.com/kubeflow/pipelines/backend/src/common/util"
 	k8sapi "github.com/kubeflow/pipelines/backend/src/crd/kubernetes/v2beta1"
-	"github.com/minio/minio-go/v7"
-	"github.com/minio/minio-go/v7/pkg/credentials"
 	"gorm.io/driver/mysql"
 	"gorm.io/driver/postgres"
 	"gorm.io/gorm"
@@ -952,15 +953,15 @@ func initBlobObjectStore(ctx context.Context, initConnectionTimeout time.Duratio
 		return nil, fmt.Errorf("failed to build config from environment variables: %w", err)
 	}
 
+	if err := ensureBucketExists(ctx, blobConfig); err != nil {
+		glog.Warningf("Failed to ensure bucket exists (may already exist): %v", err)
+	}
+
 	bucket, err := openBucketWithRetry(ctx, blobConfig, initConnectionTimeout)
 	if err != nil {
 		return nil, fmt.Errorf("failed to open blob storage bucket: %w", err)
 	}
 
-	if err := ensureBucketExists(ctx, blobConfig); err != nil {
-		glog.Warningf("Failed to ensure bucket exists (may already exist): %v", err)
-	}
-
 	glog.Infof("Successfully initialized blob storage for bucket: %s", blobConfig.bucketName)
 	return storage.NewBlobObjectStore(bucket, pipelinePath), nil
 }
@@ -975,6 +976,11 @@ type blobStorageConfig struct {
 	secretKey  string
 }
 
+type s3BucketAPI interface {
+	HeadBucket(ctx context.Context, params *s3.HeadBucketInput, optFns ...func(*s3.Options)) (*s3.HeadBucketOutput, error)
+	CreateBucket(ctx context.Context, params *s3.CreateBucketInput, optFns ...func(*s3.Options)) (*s3.CreateBucketOutput, error)
+}
+
 // ensureProtocol adds http:// or https:// protocol if not present
 func ensureProtocol(endpoint string, secure bool) string {
 	if strings.HasPrefix(endpoint, "http://") || strings.HasPrefix(endpoint, "https://") {
@@ -1021,46 +1027,68 @@ func buildConfigFromEnvVars() (*blobStorageConfig, error) {
 	}, nil
 }
 
-func validateRequiredConfig(bucketName string, host string, accessKey string, secretKey string) error {
+func newS3BucketClient(ctx context.Context, config *blobStorageConfig) (*s3.Client, error) {
+	awsCfg, err := loadAWSConfig(ctx, config)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create AWS config: %w", err)
+	}
+
+	endpointWithProtocol := ensureProtocol(config.endpoint, config.secure)
+	s3Client := s3.NewFromConfig(awsCfg, func(o *s3.Options) {
+		o.BaseEndpoint = awsv2.String(endpointWithProtocol)
+		o.UsePathStyle = true
+	})
+
+	return s3Client, nil
+}
+
+func loadAWSConfig(ctx context.Context, config *blobStorageConfig) (awsv2.Config, error) {
+	opts := []func(*awsv2cfg.LoadOptions) error{
+		awsv2cfg.WithRegion(config.region),
+	}
+	if config.accessKey != "" && config.secretKey != "" {
+		opts = append(opts, awsv2cfg.WithCredentialsProvider(
+			awsv2creds.NewStaticCredentialsProvider(config.accessKey, config.secretKey, ""),
+		))
+	}
+	cfg, err := awsv2cfg.LoadDefaultConfig(ctx, opts...)
+	if err != nil {
+		return awsv2.Config{}, err
+	}
+	return cfg, nil
+}
+
+// validateRequiredConfig validates the required object store configuration fields.
+// bucketName and host are always required. Credentials (accessKey/secretKey) are optional
+// to support AWS IRSA (IAM Roles for Service Accounts), environment variables,
+// and instance profile-based authentication through the default AWS credential chain.
+// However, if credentials are provided, both accessKey and secretKey must be set.
+func validateRequiredConfig(bucketName, host, accessKey, secretKey string) error {
 	if bucketName == "" {
 		return fmt.Errorf("ObjectStoreConfig.BucketName is required")
 	}
 	if host == "" {
 		return fmt.Errorf("ObjectStoreConfig.Host is required")
 	}
-	if accessKey == "" {
-		return fmt.Errorf("ObjectStoreConfig.AccessKey is required")
-	}
-	if secretKey == "" {
-		return fmt.Errorf("ObjectStoreConfig.SecretAccessKey is required")
+	if (accessKey != "") != (secretKey != "") {
+		return fmt.Errorf("ObjectStoreConfig.AccessKey and ObjectStoreConfig.SecretAccessKey must both be set or both be empty")
 	}
 	return nil
 }
 
-// openBucketWithRetry opens a blob bucket using AWS SDK v2 with explicit credentials and retry logic
+// openBucketWithRetry opens a blob bucket using AWS SDK v2 with retry logic.
+// When accessKey and secretKey are empty, it uses the default credential chain
+// (supports IRSA, environment variables, instance profiles, etc.)
 func openBucketWithRetry(ctx context.Context, config *blobStorageConfig, timeout time.Duration) (*blob.Bucket, error) {
 	var bucket *blob.Bucket
 	var err error
 
 	operation := func() error {
-		cfg, err := awsv2cfg.LoadDefaultConfig(ctx,
-			awsv2cfg.WithRegion(config.region),
-			awsv2cfg.WithCredentialsProvider(awsv2creds.NewStaticCredentialsProvider(
-				config.accessKey,
-				config.secretKey,
-				"",
-			)),
-		)
+		s3Client, err := newS3BucketClient(ctx, config)
 		if err != nil {
-			return fmt.Errorf("failed to create AWS config: %w", err)
+			return err
 		}
 
-		endpointWithProtocol := ensureProtocol(config.endpoint, config.secure)
-		s3Client := s3.NewFromConfig(cfg, func(o *s3.Options) {
-			o.BaseEndpoint = awsv2.String(endpointWithProtocol)
-			o.UsePathStyle = true
-		})
-
 		bucket, err = s3blob.OpenBucketV2(ctx, s3Client, config.bucketName, nil)
 		return err
 	}
@@ -1076,38 +1104,86 @@ func openBucketWithRetry(ctx context.Context, config *blobStorageConfig, timeout
 	return bucket, nil
 }
 
-func createMinioBucket(ctx context.Context, minioClient *minio.Client, bucketName, region string) {
-	// Check to see if it exists, and we have permission to access it.
-	exists, err := minioClient.BucketExists(ctx, bucketName)
-	if err != nil {
-		glog.Fatalf("Failed to check if object store bucket exists. Error: %v", err)
-	}
-	if exists {
-		glog.Infof("We already own %s\n", bucketName)
-		return
-	}
-	// Create bucket if it does not exist
-	err = minioClient.MakeBucket(ctx, bucketName, minio.MakeBucketOptions{Region: region})
+// ensureBucketExists creates the bucket if it doesn't exist.
+// It relies on the AWS SDK default credential chain (plus optional static creds) so IRSA/web-identity
+// tokens, environment variables, and instance profiles are all supported.
+func ensureBucketExists(ctx context.Context, config *blobStorageConfig) error {
+	s3Client, err := newS3BucketClient(ctx, config)
 	if err != nil {
-		glog.Fatalf("Failed to create object store bucket. Error: %v", err)
+		return fmt.Errorf("failed to create S3 client: %w", err)
 	}
-	glog.Infof("Successfully created bucket %s\n", bucketName)
+
+	return ensureBucketExistsWithClient(ctx, s3Client, config)
 }
 
-// ensureBucketExists creates a bucket if it doesn't exist
-func ensureBucketExists(ctx context.Context, config *blobStorageConfig) error {
-	minioClient, err := minio.New(config.endpoint, &minio.Options{
-		Creds:  credentials.NewStaticV4(config.accessKey, config.secretKey, ""),
-		Secure: config.secure,
+func ensureBucketExistsWithClient(ctx context.Context, client s3BucketAPI, config *blobStorageConfig) error {
+	_, err := client.HeadBucket(ctx, &s3.HeadBucketInput{
+		Bucket: awsv2.String(config.bucketName),
 	})
+	if err == nil {
+		glog.Infof("Bucket %s already exists and is accessible", config.bucketName)
+		return nil
+	}
+
+	if !isBucketNotFoundError(err) {
+		return fmt.Errorf("failed to check if bucket %s exists: %w", config.bucketName, err)
+	}
+
+	glog.Infof("Bucket %s not found, attempting to create", config.bucketName)
+	_, err = client.CreateBucket(ctx, buildCreateBucketInput(config))
 	if err != nil {
-		return fmt.Errorf("failed to create MinIO client: %w", err)
+		if isBucketAlreadyOwnedByUs(err) {
+			glog.Infof("Bucket %s was created concurrently by us", config.bucketName)
+			return nil
+		}
+		return fmt.Errorf("failed to create object store bucket: %w", err)
 	}
 
-	createMinioBucket(ctx, minioClient, config.bucketName, config.region)
+	glog.Infof("Successfully created bucket %s", config.bucketName)
 	return nil
 }
 
+func buildCreateBucketInput(config *blobStorageConfig) *s3.CreateBucketInput {
+	input := &s3.CreateBucketInput{
+		Bucket: awsv2.String(config.bucketName),
+	}
+	if config.region != "" && config.region != "us-east-1" {
+		input.CreateBucketConfiguration = &s3types.CreateBucketConfiguration{
+			LocationConstraint: s3types.BucketLocationConstraint(config.region),
+		}
+	}
+
+	return input
+}
+
+func isBucketNotFoundError(err error) bool {
+	var notFound *s3types.NotFound
+	if errors.As(err, &notFound) {
+		return true
+	}
+	var noSuchBucket *s3types.NoSuchBucket
+	if errors.As(err, &noSuchBucket) {
+		return true
+	}
+	var apiErr smithy.APIError
+	if errors.As(err, &apiErr) {
+		code := apiErr.ErrorCode()
+		return code == "NotFound" || code == "NoSuchBucket" || code == "404"
+	}
+	return false
+}
+
+// isBucketAlreadyOwnedByUs returns true only for BucketAlreadyOwnedByYou errors,
+// which indicates a race condition where we created the bucket concurrently.
+// BucketAlreadyExists (bucket owned by another account on AWS) is NOT suppressed
+// so it surfaces in logs as a warning, helping detect misconfiguration.
+// Note: SeaweedFS/MinIO return BucketAlreadyExists even for buckets you own,
+// but since ensureBucketExists failures are just warnings, this is acceptable.
+func isBucketAlreadyOwnedByUs(err error) bool {
+	var owned *s3types.BucketAlreadyOwnedByYou
+	return errors.As(err, &owned)
+}
+
 func initLogArchive() (logArchive archive.LogArchiveInterface) {
 	logFileName := common.GetStringConfigWithDefault(archiveLogFileName, "")
 	logPathPrefix := common.GetStringConfigWithDefault(archiveLogPathPrefix, "")