Downloading an Object - Obtaining the Download Progress (SDK for Go)

package main
import (
    "fmt"
    "os"

    obs "github.com/huaweicloud/huaweicloud-sdk-go-obs/obs"
)

type ObsProgressListener struct {
}

// Define the function for processing progress change events.
func (listener *ObsProgressListener) ProgressChanged(event *obs.ProgressEvent) {
    switch event.EventType {
    case obs.TransferStartedEvent:
        fmt.Printf("Transfer Started, ConsumedBytes: %d, TotalBytes %d.\n",
            event.ConsumedBytes, event.TotalBytes)
    case obs.TransferDataEvent:
        fmt.Printf("\rTransfer Data, ConsumedBytes: %d, TotalBytes %d, %d%%.\n",
            event.ConsumedBytes, event.TotalBytes, event.ConsumedBytes*100/event.TotalBytes)
    case obs.TransferCompletedEvent:
        fmt.Printf("\nTransfer Completed, ConsumedBytes: %d, TotalBytes %d.\n",
            event.ConsumedBytes, event.TotalBytes)
    case obs.TransferFailedEvent:
        fmt.Printf("\nTransfer Failed, ConsumedBytes: %d, TotalBytes %d.\n",
            event.ConsumedBytes, event.TotalBytes)
    default:
    }
}

func main() {
    //Obtain an AK/SK pair using environment variables or import the AK/SK pair in other ways. Using hard coding may result in leakage.
    //Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
    ak := os.Getenv("AccessKeyID")
    sk := os.Getenv("SecretAccessKey")
    // (Optional) If you use a temporary AK/SK pair and a security token to access OBS, you are not advised to use hard coding, which may result in information leakage. You can obtain an AK/SK pair using environment variables or import an AK/SK pair in other ways.
    // securityToken := os.Getenv("SecurityToken")


    // Enter the endpoint corresponding to the bucket. CN-Hong Kong is used here as an example. Replace it with the one currently in use.
    endPoint := "https://obs.ap-southeast-1.myhuaweicloud.com"




    // Create an obsClient instance.
    // If you use a temporary AK/SK pair and a security token to access OBS, use the obs.WithSecurityToken method to specify a security token when creating an instance.
    obsClient, err := obs.New(ak, sk, endPoint/*, obs.WithSecurityToken(securityToken)*/)
    if err != nil {
        fmt.Printf("Create obsClient error, errMsg: %s", err.Error())
    }
    input := &obs.GetObjectInput{}
    // Specify the bucket name.
    input.Bucket = "examplebucket"
    // Specify the object (example/objectname as an example) to download.
    input.Key = "example/objectname"
    // Download the object using streaming.
    output, err := obsClient.GetObject(input, obs.WithProgress(&ObsProgressListener{}))
    if err == nil {
        // The output.Body must be closed after use to prevent connection leakage.
        defer output.Body.Close()
        fmt.Printf("Get object(%s) under the bucket(%s) successful!\n", input.Key, input.Bucket)
        fmt.Printf("StorageClass:%s, ETag:%s, ContentType:%s, ContentLength:%d, LastModified:%s\n",
            output.StorageClass, output.ETag, output.ContentType, output.ContentLength, output.LastModified)
        // Read the object content.
        p := make([]byte, 1024)
        var readErr error
        var readCount int
        for {
            readCount, readErr = output.Body.Read(p)
            if readCount > 0 {
                fmt.Printf("%s", p[:readCount])
            }
            if readErr != nil {
                break
            }
        }
        return
    }
    fmt.Printf("List objects under the bucket(%s) fail!\n", input.Bucket)
    if obsError, ok := err.(obs.ObsError); ok {
        fmt.Println("An ObsError was found, which means your request sent to OBS was rejected with an error response.")
        fmt.Println(obsError.Error())
    } else {
        fmt.Println("An Exception was found, which means the client encountered an internal problem when attempting to communicate with OBS, for example, the client was unable to access the network.")
        fmt.Println(err)
    }
}

package main
import (
    "fmt"
    "os"

    obs "github.com/huaweicloud/huaweicloud-sdk-go-obs/obs"
)

type ObsProgressListener struct {
}

// Define the function for processing progress change events.
func (listener *ObsProgressListener) ProgressChanged(event *obs.ProgressEvent) {
    switch event.EventType {
    case obs.TransferStartedEvent:
        fmt.Printf("Transfer Started, ConsumedBytes: %d, TotalBytes %d.\n",
            event.ConsumedBytes, event.TotalBytes)
    case obs.TransferDataEvent:
        fmt.Printf("\rTransfer Data, ConsumedBytes: %d, TotalBytes %d, %d%%.\n",
            event.ConsumedBytes, event.TotalBytes, event.ConsumedBytes*100/event.TotalBytes)
    case obs.TransferCompletedEvent:
        fmt.Printf("\nTransfer Completed, ConsumedBytes: %d, TotalBytes %d.\n",
            event.ConsumedBytes, event.TotalBytes)
    case obs.TransferFailedEvent:
        fmt.Printf("\nTransfer Failed, ConsumedBytes: %d, TotalBytes %d.\n",
            event.ConsumedBytes, event.TotalBytes)
    default:
    }
}

func main() {
    //Obtain an AK/SK pair using environment variables or import the AK/SK pair in other ways. Using hard coding may result in leakage.
    //Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
    ak := os.Getenv("AccessKeyID")
    sk := os.Getenv("SecretAccessKey")
    // (Optional) If you use a temporary AK/SK pair and a security token to access OBS, you are not advised to use hard coding, which may result in information leakage. You can obtain an AK/SK pair using environment variables or import an AK/SK pair in other ways.
    // securityToken := os.Getenv("SecurityToken")


    // Enter the endpoint corresponding to the bucket. CN-Hong Kong is used here as an example. Replace it with the one currently in use.
    endPoint := "https://obs.ap-southeast-1.myhuaweicloud.com"




    // Create an obsClient instance.
    // If you use a temporary AK/SK pair and a security token to access OBS, use the obs.WithSecurityToken method to specify a security token when creating an instance.
    obsClient, err := obs.New(ak, sk, endPoint/*, obs.WithSecurityToken(securityToken)*/)
    if err != nil {
        fmt.Printf("Create obsClient error, errMsg: %s", err.Error())
    }
    input := &obs.DownloadFileInput{}
    // Specify the bucket name.
    input.Bucket = "examplebucket"
    // Specify the object (example/objectname as an example) to download.
    input.Key = "example/objectname"
    // Specify a local full path (/tmp/objectname as an example) for the specified object. If the path is left blank, the current working directory will be used by default.
    input.DownloadFile = "/tmp/objectname"
    // Specify whether to enable resumable download (true as an example). The default value is false, indicating that resumable download is disabled.
    input.EnableCheckpoint = true
    // Specify a part size, in bytes. This example sets each part to 9 MB.
    input.PartSize = 9 * 1024 * 1024
    // Specify the maximum number of parts that can be concurrently downloaded. 5 is used as an example.
    input.TaskNum = 5
    // Download the object using resumable download.
    output, err := obsClient.DownloadFile(input, obs.WithProgress(&ObsProgressListener{}))
    if err == nil {
        fmt.Printf("Download file(%s) under the bucket(%s) successful!\n", input.Key, input.Bucket)
        fmt.Printf("StorageClass:%s, ETag:%s, ContentType:%s, ContentLength:%d, LastModified:%s\n",
            output.StorageClass, output.ETag, output.ContentType, output.ContentLength, output.LastModified)
        return
    }
    fmt.Printf("Download file(%s) under the bucket(%s) fail!\n", input.Key, input.Bucket)
    if obsError, ok := err.(obs.ObsError); ok {
        fmt.Println("An ObsError was found, which means your request sent to OBS was rejected with an error response.")
        fmt.Println(obsError.Error())
    } else {
        fmt.Println("An Exception was found, which means the client encountered an internal problem when attempting to communicate with OBS, for example, the client was unable to access the network.")
        fmt.Println(err)
    }
}