Add credential storage (#6938)

* add credential store interface

* load credential.toml

* lint

* create credentialManager with explicit store type

* add type name

* InitializeCredentialManager

* remove unused functions

* fix missing import

* fix import

* fix nil configuration

weed/credential/credential_store.go

@@ -0,0 +1,91 @@
+package credential
+
+import (
+	"context"
+	"errors"
+	"time"
+
+	"github.com/seaweedfs/seaweedfs/weed/pb/iam_pb"
+	"github.com/seaweedfs/seaweedfs/weed/util"
+)
+
+var (
+	ErrUserNotFound      = errors.New("user not found")
+	ErrUserAlreadyExists = errors.New("user already exists")
+	ErrAccessKeyNotFound = errors.New("access key not found")
+)
+
+// CredentialStoreTypeName represents the type name of a credential store
+type CredentialStoreTypeName string
+
+// Credential store name constants
+const (
+	StoreTypeMemory   CredentialStoreTypeName = "memory"
+	StoreTypeFilerEtc CredentialStoreTypeName = "filer_etc"
+	StoreTypePostgres CredentialStoreTypeName = "postgres"
+	StoreTypeSQLite   CredentialStoreTypeName = "sqlite"
+)
+
+// CredentialStore defines the interface for user credential storage and retrieval
+type CredentialStore interface {
+	// GetName returns the name of the credential store implementation
+	GetName() CredentialStoreTypeName
+
+	// Initialize initializes the credential store with configuration
+	Initialize(configuration util.Configuration, prefix string) error
+
+	// LoadConfiguration loads the entire S3 API configuration
+	LoadConfiguration(ctx context.Context) (*iam_pb.S3ApiConfiguration, error)
+
+	// SaveConfiguration saves the entire S3 API configuration
+	SaveConfiguration(ctx context.Context, config *iam_pb.S3ApiConfiguration) error
+
+	// CreateUser creates a new user with the given identity
+	CreateUser(ctx context.Context, identity *iam_pb.Identity) error
+
+	// GetUser retrieves a user by username
+	GetUser(ctx context.Context, username string) (*iam_pb.Identity, error)
+
+	// UpdateUser updates an existing user
+	UpdateUser(ctx context.Context, username string, identity *iam_pb.Identity) error
+
+	// DeleteUser removes a user by username
+	DeleteUser(ctx context.Context, username string) error
+
+	// ListUsers returns all usernames
+	ListUsers(ctx context.Context) ([]string, error)
+
+	// GetUserByAccessKey retrieves a user by access key
+	GetUserByAccessKey(ctx context.Context, accessKey string) (*iam_pb.Identity, error)
+
+	// CreateAccessKey creates a new access key for a user
+	CreateAccessKey(ctx context.Context, username string, credential *iam_pb.Credential) error
+
+	// DeleteAccessKey removes an access key for a user
+	DeleteAccessKey(ctx context.Context, username string, accessKey string) error
+
+	// Shutdown performs cleanup when the store is being shut down
+	Shutdown()
+}
+
+// AccessKeyInfo represents access key information with metadata
+type AccessKeyInfo struct {
+	AccessKey string    `json:"accessKey"`
+	SecretKey string    `json:"secretKey"`
+	Username  string    `json:"username"`
+	CreatedAt time.Time `json:"createdAt"`
+}
+
+// UserCredentials represents a user's credentials and metadata
+type UserCredentials struct {
+	Username    string               `json:"username"`
+	Email       string               `json:"email"`
+	Account     *iam_pb.Account      `json:"account,omitempty"`
+	Credentials []*iam_pb.Credential `json:"credentials"`
+	Actions     []string             `json:"actions"`
+	CreatedAt   time.Time            `json:"createdAt"`
+	UpdatedAt   time.Time            `json:"updatedAt"`
+}
+
+// Stores holds all available credential store implementations
+var Stores []CredentialStore