storage

README

go-storage

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A vendor-neutral storage library for Golang.

Vision

Write once, run on every storage service.

Goal

• Vendor agnostic
• Production ready
• High performance

Examples

package main

import (
    "log"

    "github.com/rgglez/go-storage/v5/services"
    "github.com/rgglez/go-storage/v5/types"

    // Add fs support
    _ "github.com/rgglez/go-storage/services/fs/v4"
    // Add s3 support
    _ "github.com/rgglez/go-storage/services/s3/v3"
    // Add gcs support
    _ "github.com/rgglez/go-storage/services/gcs/v3"
    // Add azblob support
    _ "github.com/rgglez/go-storage/services/azblob/v3"
    // More support could be found under BeyondStorage.
    _ "github.com/rgglez/go-storage/services/xxx" 
)

func main() {
    // Init a Storager from connection string. 
    store, err := services.NewStoragerFromString("s3://bucket_name/path/to/workdir")
    if err != nil {
        log.Fatalf("service init failed: %v", err)
    }

    // Write data from io.Reader into hello.txt
    n, err := store.Write("hello.txt", r, length)

    // Read data from hello.txt to io.Writer
    n, err := store.Read("hello.txt", w)

    // Stat hello.txt to check existence or get its metadata
    o, err := store.Stat("hello.txt")

    // Use object's functions to get metadata
    length, ok := o.GetContentLength()
    
    // List will create an iterator of object under path.
    it, err := store.List("path")
    
    for {
    	// Use iterator.Next to retrieve next object until we meet IterateDone.
    	o, err := it.Next()
    	if errors.Is(err, types.IterateDone) {
    		break
        }
    }

    // Delete hello.txt
    err = store.Delete("hello.txt")
}

More examples could be found at go-storage-example.

Features

Widely native services support

16 stable services that have passed all integration tests.

• azblob: Azure Blob storage
• bos: Baidu Object Storage
• cos: Tencent Cloud Object Storage
• dropbox: Dropbox
• fs: Local file system
• ftp: FTP
• gcs: Google Cloud Storage
• gdrive: Google Drive
• ipfs: InterPlanetary File System
• kodo: qiniu kodo
• memory: data that only in memory
• minio: MinIO
• obs: Huawei Object Storage Service
• oss: Aliyun Object Storage
• qingstor: QingStor Object Storage
• s3: Amazon S3

3 beta services that implemented required functions, but not passed integration tests.

• hdfs: Hadoop Distributed File System
• tar: tar files
• uss: UPYUN Storage Service

4 alpha services that still under development.

• onedrive: Microsoft OneDrive
• storj: StorJ
• webdav: WebDAV
• zip: zip files

More service ideas could be found at Service Integration Tracking.

Complete and easily extensible interface

Basic operations

• Metadata: get Storager metadata

meta := store.Metadata()
_ := meta.GetWorkDir() // Get object WorkDir
_, ok := meta.GetWriteSizeMaximum() // Get the maximum size for write operation

• Read: read Object content

// Read 2048 byte at the offset 1024 into the io.Writer.
n, err := store.Read("path", w, pairs.WithOffset(1024), pairs.WithSize(2048))

• Write: write content into Object

// Write 2048 byte from io.Reader
n, err := store.Write("path", r, 2048)

• Stat: get Object metadata or check existences

o, err := store.Stat("path")
if errors.Is(err, services.ErrObjectNotExist) {
	// object is not exist
}
length, ok := o.GetContentLength() // get the object content length.

• Delete: delete an Object

err := store.Delete("path") // Delete the object "path"

• List: list Object in given prefix or dir

it, err := store.List("path")
for {
	o, err := it.Next()
	if err != nil && errors.Is(err, types.IterateDone) {
        // the list is over 
    }
    length, ok := o.GetContentLength() // get the object content length.
}

Extended operations

• Copy: copy a Object inside storager

err := store.(Copier).Copy(src, dst) // Copy an object from src to dst.

• Move: move a Object inside storager

err := store.(Mover).Move(src, dst) // Move an object from src to dst.

• Reach: generate a public accessible url to an Object

url, err := store.(Reacher).Reach("path") // Generate an url to the object.

• Dir: Dir Object support

o, err := store.(Direr).CreateDir("path") // Create a dir object.

Large file manipulation

• Multipart: allow doing multipart uploads

ms := store.(Multiparter)

// Create a multipart object.
o, err := ms.CreateMultipart("path")
// Write 1024 bytes from io.Reader into a multipart at index 1
n, part, err := ms.WriteMultipart(o, r, 1024, 1)
// Complete a multipart object.
err := ms.CompleteMultipart(o, []*Part{part})

• Append: allow appending to an object

as := store.(Appender)

// Create an appendable object.
o, err := as.CreateAppend("path")
// Write 1024 bytes from io.Reader.
n, err := as.WriteAppend(o, r, 1024)
// Commit an append object.
err = as.CommitAppend(o)

• Block: allow combining an object with block ids

bs := store.(Blocker)

// Create a block object.
o, err := bs.CreateBlock("path")
// Write 1024 bytes from io.Reader with block id "id-abc"
n, err := bs.WriteBlock(o, r, 1024, "id-abc")
// Combine block via block ids.
err := bs.CombineBlock(o, []string{"id-abc"})

• Page: allow doing random writes

ps := store.(Pager)

// Create a page object.
o, err := ps.CreatePage("path")
// Write 1024 bytes from io.Reader at offset 2048
n, err := ps.WritePage(o, r, 1024, 2048)

Comprehensive metadata

Global object metadata

• id: unique key in service
• name: relative path towards service's work dir
• mode: object mode can be a combination of read, dir, part and more
• etag: entity tag as defined in rfc2616
• content-length: object's content size.
• content-md5: md5 digest as defined in rfc2616
• content-type: media type as defined in rfc2616
• last-modified: object's last updated time.

System object metadata

Service system object metadata like storage-class and so on.

o, err := store.Stat("path")

// Get service system metadata via API provides by go-service-s3.
om := s3.GetObjectSystemMetadata(o)
_ = om.StorageClass // this object's storage class
_ = om.ServerSideEncryptionCustomerAlgorithm // this object's sse algorithm

Strong Typing Everywhere

Self maintained codegen definitions helps to generate all our APIs, pairs and metadata.

Generated pairs which can be used as API optional arguments.

func WithContentMd5(v string) Pair {
    return Pair{
        Key:   "content_md5",
        Value: v,
    }
}

Generated object metadata which can be used to get content md5 from object.

func (o *Object) GetContentMd5() (string, bool) {
    o.stat()
    
    if o.bit&objectIndexContentMd5 != 0 {
        return o.contentMd5, true
    }
    
    return "", false
}

Server-Side Encrypt

Server-Side Encrypt supports via system pair and system metadata, and we can use Default Pairs to simplify the job.

func NewS3SseC(key []byte) (types.Storager, error) {
    defaultPairs := s3.DefaultStoragePairs{
        Write: []types.Pair{
            // Required, must be AES256
            s3.WithServerSideEncryptionCustomerAlgorithm(s3.ServerSideEncryptionAes256),
            // Required, your AES-256 key, a 32-byte binary value
            s3.WithServerSideEncryptionCustomerKey(key),
        },
        // Now you have to provide customer key to read encrypted data
        Read: []types.Pair{
            // Required, must be AES256
            s3.WithServerSideEncryptionCustomerAlgorithm(s3.ServerSideEncryptionAes256),
            // Required, your AES-256 key, a 32-byte binary value
            s3.WithServerSideEncryptionCustomerKey(key),
        }}
    
    return s3.NewStorager(..., s3.WithDefaultStoragePairs(defaultPairs))
}

Sponsor

Documentation

Overview

Package storage intends to provide a unified storage layer for Golang.

Goals

- Production ready: high test coverage, enterprise storage software adaptation, semantic versioning, well documented.

- High performance: more code generation, less runtime reflect.

- Vendor agnostic: more generic abstraction, less internal details.

Examples

The most common case to use a Storager service could be following:

1. Init a storager.

    store, err := fs.NewStorager(pairs.WithWorkDir("/tmp"))
	if err != nil {
		log.Fatalf("service init failed: %v", err)
	}

2. Use Storager API to maintain data.

var buf bytes.Buffer

n, err := store.Read("path/to/file", &buf)
if err != nil {
	log.Printf("storager read: %v", err)
}