COCOS-151 - Add compression/decompression option for CLI/Agent (#200)

* on the fly compression

Signed-off-by: Sammy Oina <sammyoina@gmail.com>

* rename file-hash to checksum

Signed-off-by: Sammy Oina <sammyoina@gmail.com>

* check error properly

Signed-off-by: Sammy Oina <sammyoina@gmail.com>

* fix lint

Signed-off-by: Sammy Oina <sammyoina@gmail.com>

* fix connection handling

Signed-off-by: Sammy Oina <sammyoina@gmail.com>

---------

Signed-off-by: Sammy Oina <sammyoina@gmail.com>

internal/file.go

@@ -3,9 +3,12 @@
 package internal
 
 import (
+	"encoding/hex"
 	"io"
 	"os"
 	"path/filepath"
+
+	"golang.org/x/crypto/sha3"
 )
 
 // CopyFile copies a file from srcPath to dstPath.
@@ -46,3 +49,37 @@ func DeleteFilesInDir(dirPath string) error {
 
 	return nil
 }
+
+// Checksum calculates the SHA3-256 checksum of the file or directory at path.
+func Checksum(path string) ([]byte, error) {
+	file, err := os.Stat(path)
+	if err != nil {
+		return nil, err
+	}
+
+	if file.IsDir() {
+		f, err := ZipDirectoryToMemory(path)
+		if err != nil {
+			return nil, err
+		}
+		sum := sha3.Sum256(f)
+		return sum[:], nil
+	} else {
+		f, err := os.ReadFile(path)
+		if err != nil {
+			return nil, err
+		}
+
+		sum := sha3.Sum256(f)
+		return sum[:], nil
+	}
+}
+
+// ChecksumHex calculates the SHA3-256 checksum of the file or directory at path and returns it as a hex-encoded string.
+func ChecksumHex(path string) (string, error) {
+	sum, err := Checksum(path)
+	if err != nil {
+		return "", err
+	}
+	return hex.EncodeToString(sum), nil
+}

internal/zip.go

@@ -0,0 +1,102 @@
+// Copyright (c) Ultraviolet
+// SPDX-License-Identifier: Apache-2.0
+package internal
+
+import (
+	"archive/zip"
+	"bytes"
+	"io"
+	"os"
+	"path/filepath"
+)
+
+func ZipDirectoryToMemory(sourceDir string) ([]byte, error) {
+	buf := new(bytes.Buffer)
+	zipWriter := zip.NewWriter(buf)
+
+	err := filepath.Walk(sourceDir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		if info.IsDir() {
+			return nil
+		}
+
+		relPath, err := filepath.Rel(sourceDir, path)
+		if err != nil {
+			return err
+		}
+
+		zipHeader, err := zip.FileInfoHeader(info)
+		if err != nil {
+			return err
+		}
+		zipHeader.Name = relPath
+
+		zipWriterEntry, err := zipWriter.CreateHeader(zipHeader)
+		if err != nil {
+			return err
+		}
+
+		fileToZip, err := os.Open(path)
+		if err != nil {
+			return err
+		}
+		defer fileToZip.Close()
+
+		_, err = io.Copy(zipWriterEntry, fileToZip)
+		return err
+	})
+	if err != nil {
+		zipWriter.Close()
+		return nil, err
+	}
+
+	if err := zipWriter.Close(); err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+func UnzipFromMemory(zipData []byte, targetDir string) error {
+	reader := bytes.NewReader(zipData)
+	zipReader, err := zip.NewReader(reader, int64(len(zipData)))
+	if err != nil {
+		return err
+	}
+
+	for _, file := range zipReader.File {
+		filePath := filepath.Join(targetDir, file.Name)
+
+		if file.FileInfo().IsDir() {
+			if err := os.MkdirAll(filePath, os.ModePerm); err != nil {
+				return err
+			}
+			continue
+		}
+
+		if err := os.MkdirAll(filepath.Dir(filePath), os.ModePerm); err != nil {
+			return err
+		}
+
+		srcFile, err := file.Open()
+		if err != nil {
+			return err
+		}
+		defer srcFile.Close()
+
+		dstFile, err := os.Create(filePath)
+		if err != nil {
+			return err
+		}
+		defer dstFile.Close()
+
+		if _, err := io.Copy(dstFile, srcFile); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}