OSS SDK for Goを使用して一般的な操作を実行する方法 - Object Storage Service

このトピックでは、Object Storage Service (OSS) SDK for Goを使用して一般的な操作を実行する方法について説明します。 OSS SDK for Goのインストール方法、アクセス資格情報の設定方法、およびバケットの作成とアップロード、オブジェクトのダウンロード、一覧表示、削除などの基本的な操作の実行方法を学習できます。

Goコンパイルとランタイム環境のインストール

[ソースからGoをインストールする] を参照して、Goコンパイルおよびランタイム環境をダウンロードしてインストールします。次のコマンドを実行して、Goがインストールされているかどうかを確認します。

go version

OSS SDK for Goのインストール

次のコマンドを実行して、コードパッケージを取得します。

go get github.com/aliyun/aliyun-oss-go-sdk/oss

アクセス資格情報の設定

OSS SDK for Goを使用する前に、アクセス資格情報を設定する必要があります。この例では、RAMユーザーのAccessKeyペアが使用されます。アクセス資格情報の設定方法の詳細については、「アクセス資格情報の設定」をご参照ください。 RAMユーザーのAccessKeyペアを取得する方法の詳細については、「CreateAccessKey」をご参照ください。

次のコマンドを実行して、RAMユーザーのAccessKeyペアを使用してアクセス資格情報を設定します。

Mac OS X/Linux/Unix

export OSS_ACCESS_KEY_ID=<ALIBABA_CLOUD_ACCESS_KEY_ID>
export OSS_ACCESS_KEY_SECRET=<ALIBABA_CLOUD_ACCESS_KEY_SECRET>

Windows

set OSS_ACCESS_KEY_ID <ALIBABA_CLOUD_ACCESS_KEY_ID>
set OSS_ACCESS_KEY_SECRET <ALIBABA_CLOUD_ACCESS_KEY_SECRET>

デモプロジェクト

次のデモでは、OSSClientインスタンスを作成し、バケットを作成し、オブジェクトをアップロード、ダウンロード、リスト、および削除する方法を示します。

デモプロジェクトのディレクトリにmain.goファイルを作成します。

package main

import (
	"log"

	"github.com/aliyun/aliyun-oss-go-sdk/oss"
)

var client *oss. Client // Specify the global variable used to store the OSSClient instance.

func main() {
	// Specify the name of the bucket. 
	bucketName := "yourBucketName"
	// Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. Specify your actual endpoint. 
	endpoint := "yourEndpoint"

	// Check whether the environment variables are configured. 
	if endpoint == "" || bucketName == "" {
		log.Fatal("Please set yourEndpoint and bucketName.")
	}

	// Obtain access credentials from environment variables. 
	provider, err := oss.NewEnvironmentVariableCredentialsProvider()
	if err != nil {
		handleError(err)
	}

	// Create an OSSClient instance. 
	// Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. Specify your actual endpoint. 
	// Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou. Specify the actual region.
	clientOptions := []oss.ClientOption{oss.SetCredentialsProvider(&provider)}
	clientOptions = append(clientOptions, oss.Region("yourRegion"))
	// Specify the version of the signature algorithm.
	clientOptions = append(clientOptions, oss.AuthVersion(oss.AuthV4))
	client, err := oss.New(endpoint, "", "", clientOptions...)
	if err != nil {
		handleError(err)
	}

	// Display the client information. 
	log.Printf("Client: %#v\n", client)

	// Sample operation: create a bucket. 
	if err := createBucket(bucketName); err != nil {
		handleError(err)
	}

	// Sample operation: upload an object. 
	objectName := "file.txt"
	localFileName := "/path/to/local/file.txt"
	if err := uploadFile(bucketName, objectName, localFileName); err != nil {
		handleError(err)
	}

	// Sample operation: download an object. 
	downloadedFileName := "/path/to/downloaded/file.txt"
	if err := downloadFile(bucketName, objectName, downloadedFileName); err != nil {
		handleError(err)
	}

	// Sample operation: list an object. 
	if err := listObjects(bucketName); err != nil {
		handleError(err)
	}

	// Sample operation: delete an object. 
	if err := deleteObject(bucketName, objectName); err != nil {
		handleError(err)
	}
}

// Call handleError to handle unrecoverable errors and terminate the program after recording the error messages. 
func handleError(err error) {
	log.Fatalf("Error: %v", err)
}

// Call CreateBucket to create an OSS bucket. 
// Specify the following parameters:
//
// bucketName: the name of the bucket. 
// endpoint: the endpoint of the region in which the bucket is located. 
//
// If the bucket is created, a log is generated. Otherwise, an error message is returned. 
func createBucket(bucketName string) error {
	// Create the bucket. 
	err := client.CreateBucket(bucketName)
	if err != nil {
		return err
	}

	// After the bucket is created, a log is generated. 
	log.Printf("Bucket created successfully: %s", bucketName)
	return nil
}

// Call uploadFile to upload a local file to an OSS bucket. 
// Specify the following parameters:
//
// bucketName: the name of the bucket. 
// objectName: the full path of the object. Do not include the bucket name in the full path. 
// localFileName: the full path of the local file. 
// endpoint: the endpoint of the region in which the bucket is located. 
//
// If the local file is uploaded, a log is generated. Otherwise, an error message is returned. 
func uploadFile(bucketName, objectName, localFileName string) error {
	// Obtain the bucket information. 
	bucket, err := client.Bucket(bucketName)
	if err != nil {
		return err
	}

	// Upload the local file. 
	err = bucket.PutObjectFromFile(objectName, localFileName)
	if err != nil {
		return err
	}

	// After the local file is uploaded, a log is generated. 
	log.Printf("File uploaded successfully to %s/%s", bucketName, objectName)
	return nil
}

// Call downloadFile to download an object from an OSS bucket to a local path. 
// Specify the following parameters:
//
// bucketName: the name of the bucket. 
// objectName: the full path of the object. Do not include the bucket name in the full path. 
// downloadedFileName: the full path of the local file that you want to store the downloaded object. 
// endpoint: the endpoint of the region in which the bucket is located. 
//
// If the object is downloaded, a log is generated. Otherwise, an error message is returned. 
func downloadFile(bucketName, objectName, downloadedFileName string) error {
	// Obtain the bucket information. 
	bucket, err := client.Bucket(bucketName)
	if err != nil {
		return err
	}

	// Download the object. 
	err = bucket.GetObjectToFile(objectName, downloadedFileName)
	if err != nil {
		return err
	}

	// After the object is downloaded, a log is generated. 
	log.Printf("File downloaded successfully to %s", downloadedFileName)
	return nil
}

// Call listObjects to list all objects in an OSS bucket. 
// Specify the following parameters:
//
// bucketName: the name of the bucket. 
// endpoint: the endpoint of the region in which the bucket is located. 
//
// If the objects are listed, all objects are displayed. Otherwise, an error message is returned. 
func listObjects(bucketName string) error {
	// Obtain the bucket information. 
	bucket, err := client.Bucket(bucketName)
	if err != nil {
		return err
	}

	// List objects. 
	marker := ""
	for {
		lsRes, err := bucket.ListObjects(oss.Marker(marker))
		if err != nil {
			return err
		}

		// Display the listed objects. By default, 100 objects are returned at a time. 
		for _, object := range lsRes.Objects {
			log.Printf("Object: %s", object.Key)
		}

		if !lsRes.IsTruncated {
			break
		}
		marker = lsRes.NextMarker
	}

	return nil
}

// Call deleteObject to delete an object from an OSS bucket. 
// Specify the following parameters:
//
// bucketName: the name of the bucket. 
// objectName: the name of the object that you want to delete. 
// endpoint: the endpoint of the region in which the bucket is located. 
//
// If the object is deleted, a log is generated. Otherwise, an error message is returned. 
func deleteObject(bucketName, objectName string) error {
	// Obtain the bucket information. 
	bucket, err := client.Bucket(bucketName)
	if err != nil {
		return err
	}

	// Delete the object. 
	err = bucket.DeleteObject(objectName)
	if err != nil {
		return err
	}

	// After the object is deleted, a log is generated. 
	log.Printf("Object deleted successfully: %s/%s", bucketName, objectName)
	return nil
}

main.goファイルのbucketName、endpoint、objectName、localFileName、およびdownloadedFileNameを、ビジネス要件に基づいた実際の値に置き換えます。
以下のコマンドを実行します。
```
go run main.go
```

Object Storage Service:OSS SDK for Goの使用を開始する