feat: allow injecting through stdin tar.gz on kaniko

pkg/buildcontext/buildcontext.go

@@ -38,25 +38,27 @@ type BuildContext interface {
 // parser
 func GetBuildContext(srcContext string) (BuildContext, error) {
 	split := strings.SplitAfter(srcContext, "://")
-	prefix := split[0]
-	context := split[1]
+	if len(split) > 1 {
+		prefix := split[0]
+		context := split[1]
 
-	switch prefix {
-	case constants.GCSBuildContextPrefix:
-		return &GCS{context: context}, nil
-	case constants.S3BuildContextPrefix:
-		return &S3{context: context}, nil
-	case constants.LocalDirBuildContextPrefix:
-		return &Dir{context: context}, nil
-	case constants.GitBuildContextPrefix:
-		return &Git{context: context}, nil
-	case constants.HTTPSBuildContextPrefix:
-		if util.ValidAzureBlobStorageHost(srcContext) {
-			return &AzureBlob{context: srcContext}, nil
+		switch prefix {
+		case constants.GCSBuildContextPrefix:
+			return &GCS{context: context}, nil
+		case constants.S3BuildContextPrefix:
+			return &S3{context: context}, nil
+		case constants.LocalDirBuildContextPrefix:
+			return &Dir{context: context}, nil
+		case constants.GitBuildContextPrefix:
+			return &Git{context: context}, nil
+		case constants.HTTPSBuildContextPrefix:
+			if util.ValidAzureBlobStorageHost(srcContext) {
+				return &AzureBlob{context: srcContext}, nil
+			}
+			return nil, errors.New("url provided for https context is not in a supported format, please use the https url for Azure Blob Storage")
+		case TarBuildContextPrefix:
+			return &Tar{context: context}, nil
 		}
-		return nil, errors.New("url provided for https context is not in a supported format, please use the https url for Azure Blob Storage")
-	case TarBuildContextPrefix:
-		return &Tar{context: context}, nil
 	}
 	return nil, errors.New("unknown build context prefix provided, please use one of the following: gs://, dir://, tar://, s3://, git://, https://")
 }

pkg/buildcontext/tar.go

@@ -17,11 +17,15 @@ limitations under the License.
 package buildcontext
 
 import (
+	"fmt"
+	"io/ioutil"
 	"os"
+	"path/filepath"
 
 	"github.com/GoogleContainerTools/kaniko/pkg/constants"
 	"github.com/GoogleContainerTools/kaniko/pkg/util"
 	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 )
 
 // Tar unifies calls to download and unpack the build context.
@@ -35,6 +39,23 @@ func (t *Tar) UnpackTarFromBuildContext() (string, error) {
 	if err := os.MkdirAll(directory, 0750); err != nil {
 		return "", errors.Wrap(err, "unpacking tar from build context")
 	}
+	if t.context == "stdin" {
+		fi, _ := os.Stdin.Stat()
+		if (fi.Mode() & os.ModeCharDevice) != 0 {
+			return "", fmt.Errorf("no data found.. don't forget to add the '--interactive, -i' flag")
+		}
+		logrus.Infof("To simulate EOF and exit, press 'Ctrl+D'")
+		// if launched through docker in interactive mode and without piped data
+		// process will be stuck here until EOF is sent
+		data, err := util.GetInputFrom(os.Stdin)
+		if err != nil {
+			return "", errors.Wrap(err, "fail to get standard input")
+		}
+		t.context = filepath.Join(directory, constants.ContextTar)
+		if err := ioutil.WriteFile(t.context, data, 0644); err != nil {
+			return "", errors.Wrap(err, "fail to redirect standard input into compressed tar file")
+		}
+	}
 
 	return directory, util.UnpackCompressedTar(t.context, directory)
 }