cloud: add new Uploader interface and implement for AWS

This commit adds a new `cloud.Uploader` interface that combines
the upload and register into a single operation. The rational
is that with that we avoid leaking resource if e.g. the upload
works but the registration fails.

pkg/cloud/awscloud/uploader.go

@@ -0,0 +1,116 @@
+package awscloud
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"slices"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/service/ec2"
+	"github.com/aws/aws-sdk-go/service/s3"
+	"github.com/google/uuid"
+
+	"github.com/osbuild/images/pkg/arch"
+	"github.com/osbuild/images/pkg/cloud"
+)
+
+type awsUploader struct {
+	client *AWS
+
+	region     string
+	bucketName string
+	imageName  string
+	targetArch string
+}
+
+type UploaderOptions struct {
+	TargetArch string
+}
+
+func NewUploader(region, bucketName, imageName string, opts *UploaderOptions) (cloud.Uploader, error) {
+	if opts == nil {
+		opts = &UploaderOptions{}
+	}
+
+	client, err := NewDefault(region)
+	if err != nil {
+		return nil, err
+	}
+
+	return &awsUploader{
+		client:     client,
+		region:     region,
+		bucketName: bucketName,
+		imageName:  imageName,
+		targetArch: opts.TargetArch,
+	}, nil
+}
+
+var _ cloud.Uploader = &awsUploader{}
+
+func (au *awsUploader) Check(status io.Writer) error {
+	regions, err := au.client.Regions()
+	if err != nil {
+		return fmt.Errorf("retrieving AWS regions for '%s' failed: %w", au.region, err)
+	}
+
+	if !slices.Contains(regions, au.region) {
+		return fmt.Errorf("given AWS region '%s' not found", au.region)
+	}
+
+	fmt.Fprintf(status, "Checking AWS bucket...\n")
+	buckets, err := au.client.Buckets()
+	if err != nil {
+		return fmt.Errorf("retrieving AWS list of buckets failed: %w", err)
+	}
+	if !slices.Contains(buckets, au.bucketName) {
+		return fmt.Errorf("bucket '%s' not found in the given AWS account", au.bucketName)
+	}
+
+	fmt.Fprintf(status, "Checking AWS bucket permissions...\n")
+	writePermission, err := au.client.CheckBucketPermission(au.bucketName, S3PermissionWrite)
+	if err != nil {
+		return err
+	}
+	if !writePermission {
+		return fmt.Errorf("you don't have write permissions to bucket '%s' with the given AWS account", au.bucketName)
+	}
+	fmt.Fprintf(status, "Upload conditions met.\n")
+	return nil
+}
+
+func (au *awsUploader) UploadAndRegister(r io.Reader, status io.Writer) (err error) {
+	keyName := fmt.Sprintf("%s-%s", uuid.New().String(), au.imageName)
+	fmt.Fprintf(status, "Uploading %s to %s:%s\n", au.imageName, au.bucketName, keyName)
+
+	res, err := au.client.UploadFromReader(r, au.bucketName, keyName)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if err != nil {
+			fmt.Fprintf(status, "Deleting S3 object %s:%s\n", au.bucketName, keyName)
+			_, aErr := au.client.s3.DeleteObject(&s3.DeleteObjectInput{
+				Bucket: aws.String(au.bucketName),
+				Key:    aws.String(keyName),
+			})
+			err = errors.Join(err, aErr)
+		}
+	}()
+	fmt.Fprintf(status, "File uploaded to %s\n", aws.StringValue(&res.Location))
+	if au.targetArch == "" {
+		au.targetArch = arch.Current().String()
+	}
+	bootMode := ec2.BootModeValuesUefiPreferred
+
+	fmt.Fprintf(status, "Registering AMI %s\n", au.imageName)
+	ami, snapshot, err := au.client.Register(au.imageName, au.bucketName, keyName, nil, au.targetArch, &bootMode, nil)
+	fmt.Fprintf(status, "Deleted S3 object %s:%s\n", au.bucketName, keyName)
+	fmt.Fprintf(status, "AMI registered: %s\nSnapshot ID: %s\n", aws.StringValue(ami), aws.StringValue(snapshot))
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

pkg/cloud/uploader.go

@@ -0,0 +1,24 @@
+package cloud
+
+import (
+	"io"
+)
+
+// Uploader is an interface that is returned from the actual
+// cloud implementation. The uploader will be parameterized
+// by the actual cloud implemntation, e.g.
+//
+//	awscloud.NewUploader(region, bucket, image) Uploader
+//
+// which is outside the scope of this interface.
+type Uploader interface {
+	// Check can be called before the actual upload to ensure
+	// all permissions are correct
+	Check(status io.Writer) error
+
+	// UploadAndRegister will upload the given image from
+	// the reader and write status message to the given
+	// status writer.
+	// To implement progress a proxy reader can be used.
+	UploadAndRegister(f io.Reader, status io.Writer) error
+}