feat: allow injecting through stdin tar.gz on kaniko

pkg/util/util.go

@@ -21,6 +21,7 @@ import (
 	"crypto/sha256"
 	"encoding/hex"
 	"io"
+	"io/ioutil"
 	"os"
 	"runtime"
 	"strconv"
@@ -134,3 +135,12 @@ func currentPlatform() v1.Platform {
 		Architecture: runtime.GOARCH,
 	}
 }
+
+// GetInputFrom returns Reader content
+func GetInputFrom(r io.Reader) ([]byte, error) {
+	output, err := ioutil.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+	return output, nil
+}

pkg/util/util_test.go

@@ -0,0 +1,32 @@
+/*
+Copyright 2018 Google LLC
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package util
+
+import (
+	"bufio"
+	"bytes"
+	"testing"
+
+	"github.com/GoogleContainerTools/kaniko/testutil"
+)
+
+func TestGetInputFrom(t *testing.T) {
+	validInput := []byte("Valid\n")
+	validReader := bufio.NewReader(bytes.NewReader((validInput)))
+	validValue, err := GetInputFrom(validReader)
+	testutil.CheckErrorAndDeepEqual(t, false, err, validInput, validValue)
+}