Feature/contextsources (#195)

* added switch to extract different sources as build context

* first rough implementation of aws s3

* added buildcontext package and interface

* added GetBuildContext func to buildcontext.go
added fallback to gcs
renamed GC struct to GCS

* improved the default behavior of build context retrieval

* renamed gc:// to gs:// in order to follow common standards

* renamed struct File to Dir and some cleanup work

* moved context.tar suffix to the buildcontext processors where it is needed

* added buildcontext retrieval as struct variable

added fallback if prefix in bucket specifier is present

* cleanup if structures

* added prefix to s3

* WIP

* Fixed build context bugs

* refactored build context

pkg/util/bucket_util.go

@@ -17,50 +17,14 @@ limitations under the License.
 package util
 
 import (
-	"os"
-	"path/filepath"
-
-	"cloud.google.com/go/storage"
 	"github.com/GoogleContainerTools/kaniko/pkg/constants"
-	"github.com/sirupsen/logrus"
-	"golang.org/x/net/context"
+	"strings"
 )
 
-// UnpackTarFromGCSBucket unpacks the context.tar.gz file in the given bucket to the given directory
-func UnpackTarFromGCSBucket(bucketName, directory string) error {
-	// Get the tar from the bucket
-	tarPath, err := getTarFromBucket(bucketName, directory)
-	if err != nil {
-		return err
+func GetBucketAndItem(context string) (string, string) {
+	split := strings.SplitN(context, "/", 2)
+	if len(split) == 2 {
+		return split[0], split[1]
 	}
-	logrus.Debug("Unpacking source context tar...")
-	if err := UnpackCompressedTar(tarPath, directory); err != nil {
-		return err
-	}
-	// Remove the tar so it doesn't interfere with subsequent commands
-	logrus.Debugf("Deleting %s", tarPath)
-	return os.Remove(tarPath)
-}
-
-// getTarFromBucket gets context.tar.gz from the GCS bucket and saves it to the filesystem
-// It returns the path to the tar file
-func getTarFromBucket(bucketName, directory string) (string, error) {
-	ctx := context.Background()
-	client, err := storage.NewClient(ctx)
-	if err != nil {
-		return "", err
-	}
-	bucket := client.Bucket(bucketName)
-	// Get the tarfile context.tar.gz from the GCS bucket, and save it to a tar object
-	reader, err := bucket.Object(constants.ContextTar).NewReader(ctx)
-	if err != nil {
-		return "", err
-	}
-	defer reader.Close()
-	tarPath := filepath.Join(directory, constants.ContextTar)
-	if err := CreateFile(tarPath, reader, 0600, 0, 0); err != nil {
-		return "", err
-	}
-	logrus.Debugf("Copied tarball %s from GCS bucket %s to %s", constants.ContextTar, bucketName, tarPath)
-	return tarPath, nil
+	return split[0], constants.ContextTar
 }