Resolve the helm templates

Resolving the helm templates for each of the apps
in the compositeApp by utilizing the helm libraries
and thus getting the sorted templates with all values
rendered.
This is a subtask of adding instantiation APIs.

Issue-ID: MULTICLOUD-1041
Signed-off-by: Rajamohan Raj <rajamohan.raj@intel.com>
Change-Id: Id4fddda69b5276b2409d835723b11367400ab6ea

1 files changed, 116 insertions, 0 deletions

diff --git a/src/orchestrator/utils/util-functions.go b/src/orchestrator/utils/util-functions.go
new file mode 100644
index 00000000..13c78ba4
--- /dev/null
+++ b/src/orchestrator/utils/util-functions.go
@@ -0,0 +1,116 @@
+/*
+ * Copyright 2020 Intel Corporation, Inc
+ *
+ * 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 utils
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"io"
+	"io/ioutil"
+	"os"
+	"path"
+	"path/filepath"
+
+	pkgerrors "github.com/pkg/errors"
+)
+
+//ExtractTarBall provides functionality to extract a tar.gz file
+//into a temporary location for later use.
+//It returns the path to the new location
+func ExtractTarBall(r io.Reader) (string, error) {
+	//Check if it is a valid gz
+	gzf, err := gzip.NewReader(r)
+	if err != nil {
+		return "", pkgerrors.Wrap(err, "Invalid gzip format")
+	}
+
+	//Check if it is a valid tar file
+	//Unfortunately this can only be done by inspecting all the tar contents
+	tarR := tar.NewReader(gzf)
+	first := true
+
+	outDir, _ := ioutil.TempDir("", "k8s-ext-")
+
+	for true {
+		header, err := tarR.Next()
+
+		if err == io.EOF {
+			//Check if we have just a gzip file without a tar archive inside
+			if first {
+				return "", pkgerrors.New("Empty or non-existant Tar file found")
+			}
+			//End of archive
+			break
+		}
+
+		if err != nil {
+			return "", pkgerrors.Wrap(err, "Error reading tar file")
+		}
+
+		target := filepath.Join(outDir, header.Name)
+
+		switch header.Typeflag {
+		case tar.TypeDir:
+			if _, err := os.Stat(target); err != nil {
+				// Using 755 read, write, execute for owner
+				// groups and others get read and execute permissions
+				// on the folder.
+				if err := os.MkdirAll(target, 0755); err != nil {
+					return "", pkgerrors.Wrap(err, "Creating directory")
+				}
+			}
+		case tar.TypeReg:
+			if target == outDir { // Handle '.' substituted to '' entry
+				continue
+			}
+
+			err = EnsureDirectory(target)
+			if err != nil {
+				return "", pkgerrors.Wrap(err, "Creating Directory")
+			}
+
+			f, err := os.OpenFile(target, os.O_CREATE|os.O_RDWR, os.FileMode(header.Mode))
+			if err != nil {
+				return "", pkgerrors.Wrap(err, "Creating file")
+			}
+
+			// copy over contents
+			if _, err := io.Copy(f, tarR); err != nil {
+				return "", pkgerrors.Wrap(err, "Copying file content")
+			}
+
+			// close for each file instead of a defer for all
+			// at the end of the function
+			f.Close()
+		}
+
+		first = false
+	}
+
+	return outDir, nil
+}
+
+//EnsureDirectory makes sure that the directories specified in the path exist
+//If not, it will create them, if possible.
+func EnsureDirectory(f string) error {
+	base := path.Dir(f)
+	_, err := os.Stat(base)
+	if err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	return os.MkdirAll(base, 0755)
+}