azure: add an option to tag page blobs

We want to start tagging page blobs so this commit adds a small tagging method
to our azure library and exposes it in the osbuild-upload-azure helper.

Example:

go run ./cmd/osbuild-upload-azure/ \
  -container azure-container \
  -image ./sample.vhd \
  -storage-access-key KEY \
  -storage-account account \
  -tag key:value \
  -tag hello:world \
  -tag bird:toucan

This commit also has to downgrade the azblob library version to 0.13 so the
API for blob tags is the same as the one currently shipped to Fedora.
This is suboptimal but it should unblock us for now.

Signed-off-by: Ondřej Budai <ondrej@budai.cz>

cmd/osbuild-upload-azure/main.go

@@ -1,10 +1,12 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"os"
 	"path"
+	"strings"
 
 	"github.com/osbuild/osbuild-composer/internal/upload/azure"
 )
@@ -17,17 +19,37 @@ func checkStringNotEmpty(variable string, errorMessage string) {
 	}
 }
 
+type tags map[string]string
+
+func (t *tags) String() string {
+	return ""
+}
+
+func (t *tags) Set(value string) error {
+	splitValue := strings.SplitN(value, ":", 2)
+	if len(splitValue) < 2 {
+		return fmt.Errorf(`-tag must be in format key:value, "%s" is not valid`, value)
+	}
+	key := splitValue[0]
+	val := splitValue[1]
+	(*t)[key] = val
+
+	return nil
+}
+
 func main() {
 	var storageAccount string
 	var storageAccessKey string
 	var fileName string
 	var containerName string
 	var threads int
+	tagsArg := tags(make(map[string]string))
 	flag.StringVar(&storageAccount, "storage-account", "", "Azure storage account (mandatory)")
 	flag.StringVar(&storageAccessKey, "storage-access-key", "", "Azure storage access key (mandatory)")
 	flag.StringVar(&fileName, "image", "", "image to upload (mandatory)")
 	flag.StringVar(&containerName, "container", "", "name of storage container (see Azure docs for explanation, mandatory)")
 	flag.IntVar(&threads, "threads", 16, "number of threads for parallel upload")
+	flag.Var(&tagsArg, "tag", "blob tag formatted as key:value (first colon found is considered to be the delimiter), can be specified multiple times")
 	flag.Parse()
 
 	checkStringNotEmpty(storageAccount, "You need to specify storage account")
@@ -44,18 +66,24 @@ func main() {
 	}
 
 	blobName := azure.EnsureVHDExtension(path.Base(fileName))
-
+	blobMetadata := azure.BlobMetadata{
+		StorageAccount: storageAccount,
+		BlobName:       blobName,
+		ContainerName:  containerName,
+	}
 	err = c.UploadPageBlob(
-		azure.BlobMetadata{
-			StorageAccount: storageAccount,
-			BlobName:       blobName,
-			ContainerName:  containerName,
-		},
+		blobMetadata,
 		fileName,
 		threads,
 	)
-
 	if err != nil {
-		fmt.Println("Error: ", err)
+		fmt.Println("Uploading error: ", err)
+		os.Exit(1)
+	}
+
+	err = c.TagBlob(context.Background(), blobMetadata, tagsArg)
+	if err != nil {
+		fmt.Println("Tagging error: ", err)
+		os.Exit(1)
 	}
 }