seaweedfs/weed/remote_storage/remote_storage.go

package remote_storage

import (
	"fmt"
	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
	"io"
	"strings"
	"sync"
)

type RemoteStorageLocation string

func (remote RemoteStorageLocation) NameBucketPath() (storageName, bucket, remotePath string) {
	if strings.HasSuffix(string(remote), "/") {
		remote = remote[:len(remote)-1]
	}
	parts := strings.SplitN(string(remote), "/", 3)
	if len(parts) >= 1 {
		storageName = parts[0]
	}
	if len(parts) >= 2 {
		bucket = parts[1]
	}
	remotePath = string(remote[len(storageName)+1+len(bucket):])
	if remotePath == "" {
		remotePath = "/"
	}
	return
}

type VisitFunc func(dir string, name string, isDirectory bool, remoteEntry *filer_pb.RemoteEntry) error

type RemoteStorageClient interface {
	Traverse(remote RemoteStorageLocation, visitFn VisitFunc) error
	ReadFile(bucket, key string, offset int64, size int64, writeFn func(w io.Writer) error) error
}

type RemoteStorageClientMaker interface {
	Make(remoteConf *filer_pb.RemoteConf) (RemoteStorageClient, error)
}

var (
	RemoteStorageClientMakers = make(map[string]RemoteStorageClientMaker)
	remoteStorageClients      = make(map[string]RemoteStorageClient)
	remoteStorageClientsLock  sync.Mutex
)

func makeRemoteStorageClient(remoteConf *filer_pb.RemoteConf) (RemoteStorageClient, error) {
	maker, found := RemoteStorageClientMakers[remoteConf.Type]
	if !found {
		return nil, fmt.Errorf("remote storage type %s not found", remoteConf.Type)
	}
	return maker.Make(remoteConf)
}

func GetRemoteStorage(remoteConf *filer_pb.RemoteConf) (RemoteStorageClient, error) {
	remoteStorageClientsLock.Lock()
	defer remoteStorageClientsLock.Unlock()

	existingRemoteStorageClient, found := remoteStorageClients[remoteConf.Name]
	if found {
		return existingRemoteStorageClient, nil
	}

	newRemoteStorageClient, err := makeRemoteStorageClient(remoteConf)
	if err != nil {
		return nil, fmt.Errorf("make remote storage client %s: %v", remoteConf.Name, err)
	}

	remoteStorageClients[remoteConf.Name] = newRemoteStorageClient

	return newRemoteStorageClient, nil
}