adding decompress

common/engine/compressor.go

@@ -2,10 +2,14 @@ package engine
 
 import (
 	"bytes"
-	"compress/gzip"
+	"io/ioutil"
+	"os"
+
 	"encoding/gob"
 	"fmt"
 	"io"
+
+	gzip "github.com/klauspost/pgzip"
 )
 
 type SomeStruct struct {
@@ -14,6 +18,51 @@ type SomeStruct struct {
 	C float64
 }
 
+// CompressFile uses pgzip to compress a file for storage
+func CompressFile(path string) error {
+	fileBytes, err := ioutil.ReadFile(path)
+	if err != nil {
+		return fmt.Errorf("unable to read file: %s", path)
+	}
+	file, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	w := gzip.NewWriter(file)
+	w.SetConcurrency(100000, 10)
+	bytesWritten, err := w.Write(fileBytes)
+	if err != nil {
+		return err
+	}
+	fmt.Println("%d Bytes Written", bytesWritten)
+	w.Close()
+	return nil
+}
+
+// RestoreFile takes the compressed file path and the target path and decompresses the file into the target path
+func RestoreFile(compressPath, targetPath string) error {
+	fileBytes, err := os.Open(compressPath)
+	if err != nil {
+		return fmt.Errorf("unable to read file: %s", compressPath)
+	}
+	err = os.Remove(targetPath)
+	if err != nil {
+		return fmt.Errorf("unable to remove target file to replace with decompressed file: %s", targetPath)
+	}
+	file, err := os.Create(targetPath)
+	if err != nil {
+		return err
+	}
+	r, err := gzip.NewReader(fileBytes)
+	bytesWritten, err := r.WriteTo(file)
+	if err != nil {
+		return err
+	}
+	fmt.Println("%d Bytes Written", bytesWritten)
+	r.Close()
+	return nil
+}
+
 //1.
 func StructToBytes(obj SomeStruct) (bytes.Buffer, error) {
 	//now gob this