Azure Blob Cli using the flags package

main.go

package main

import (
	"context"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"

	"github.com/Azure/azure-sdk-for-go/sdk/azidentity"
	"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob"
)

func getClient(blob, container string) azblob.BlockBlobClient {
	storageAccount := os.Getenv("AZURE_STORAGE_ACCOUNT_NAME")

	cred, err := azidentity.NewDefaultAzureCredential(nil)
	if err != nil {
		log.Fatal("Invalid credentials with error:" + err.Error())
	}

	blobUrl := fmt.Sprintf("https://%s.blob.core.windows.net/%s/%s", storageAccount, container, blob)

	client, err := azblob.NewBlockBlobClient(blobUrl, cred, nil)
	if err != nil {
		log.Fatal("Unable to create blob client")
	}
	return client
}

func upload(path, container string) {

	content, err := ioutil.ReadFile(path)
	if err != nil {
		fmt.Println(err)
	}

	_, blobName := filepath.Split(path)

	client := getClient(blobName, container)
	_, err = client.UploadBufferToBlockBlob(context.TODO(), content, azblob.HighLevelUploadToBlockBlobOption{})
	if err != nil {
		log.Fatal("Failure to upload to blob:", err)
	}
}

func download(name, container, destination string) {
	client := getClient(name, container)

	destFile, err := os.Create(destination)
	if err != nil {
		panic(err)
	}

	_ = client.DownloadBlobToFile(context.TODO(), 0, 0, destFile, azblob.HighLevelDownloadFromBlobOptions{})

}

func list(container string) {
	storageAccount := os.Getenv("AZURE_STORAGE_ACCOUNT_NAME")

	containerUrl := fmt.Sprintf("https://%s.blob.core.windows.net/%s/", storageAccount, container)

	cred, err := azidentity.NewDefaultAzureCredential(nil)
	if err != nil {
		log.Fatal("Invalid credentials with error:" + err.Error())
	}

	client, err := azblob.NewContainerClient(containerUrl, cred, nil)
	if err != nil {
		panic(err)
	}

	pager := client.ListBlobsFlat(nil)

	for pager.NextPage(context.TODO()) {
		resp := pager.PageResponse()

		for _, v := range resp.ContainerListBlobFlatSegmentResult.Segment.BlobItems {
			fmt.Println(*v.Name)
			//TODO: add results to a var and return the variable
		}
	}
}

func delete(name, container string) (azblob.BlobDeleteResponse, error) {
	client := getClient(name, container)
	return client.Delete(context.TODO(), nil)
}

func main() {
	uploadCmd := flag.NewFlagSet("upload", flag.ExitOnError)
	uploadPath := uploadCmd.String("path", "", "Path to file")
	uploadContainer := uploadCmd.String("container", "", "Name of Azure storage container")

	downloadCmd := flag.NewFlagSet("download", flag.ExitOnError)
	downloadBlobName := downloadCmd.String("name", "", "name of azure blob to download")
	downloadContainerName := downloadCmd.String("container", "", "name of azure storage container")
	downloadFile := downloadCmd.String("file", "", "destination path for file")

	listCmd := flag.NewFlagSet("list", flag.ContinueOnError)
	listContainerName := listCmd.String("container", "", "name of azure storage container")

	deleteCmd := flag.NewFlagSet("delete", flag.ExitOnError)
	deleteBlobName := deleteCmd.String("name", "", "name of azure blob to delete")
	deleteContainerName := deleteCmd.String("container", "", "name of azure storage container")

	if len(os.Args) < 2 {
		fmt.Println("expected a subcommand")
		os.Exit(1)
	}

	switch os.Args[1] {
	case "upload":
		uploadCmd.Parse(os.Args[2:])
		upload(*uploadPath, *uploadContainer)
	case "download":
		downloadCmd.Parse(os.Args[2:])
		download(*downloadBlobName, *downloadContainerName, *downloadFile)
	case "list":
		listCmd.Parse(os.Args[2:])
		list((*listContainerName))
	case "delete":
		deleteCmd.Parse(os.Args[2:])
		delete(*deleteBlobName, *deleteContainerName)
	default:
		fmt.Println("expected a subcommand")
	}
}