Download: Add sha256sum parameter to function signature

This can used to verify the downloaded file with given hash and if
this doesn't match then delete the corrupt file. This will be useful
for larger file where there is network disconnection.

Author: praveenkumar

cmd/crc-embedder/cmd/embed.go

@@ -111,7 +111,7 @@ func downloadDataFiles(goos string, destDir string) ([]string, error) {
 	downloadedFiles := []string{}
 	downloads := dataFileUrls[goos]
 	for _, dl := range downloads {
-		filename, err := download.Download(dl.url, destDir, dl.permissions)
+		filename, err := download.Download(dl.url, destDir, dl.permissions, nil)
 		if err != nil {
 			return nil, err
 		}

pkg/crc/cache/cache.go

@@ -158,7 +158,7 @@ func (c *Cache) getExecutable(destDir string) (string, error) {
 	destPath := filepath.Join(destDir, archiveName)
 	err := embed.Extract(archiveName, destPath)
 	if err != nil {
-		return download.Download(c.archiveURL, destDir, 0600)
+		return download.Download(c.archiveURL, destDir, 0600, nil)
 	}
 
 	return destPath, err

pkg/download/download.go

@@ -2,6 +2,7 @@ package download
 
 import (
 	"context"
+	"crypto/sha256"
 	"net/http"
 	"os"
 
@@ -13,7 +14,9 @@ import (
 	"github.com/pkg/errors"
 )
 
-func Download(uri, destination string, mode os.FileMode) (string, error) {
+// Download function takes sha256sum as hex decoded byte
+// something like hex.DecodeString("33daf4c03f86120fdfdc66bddf6bfff4661c7ca11c5d")
+func Download(uri, destination string, mode os.FileMode, sha256sum []byte) (string, error) {
 	logging.Debugf("Downloading %s to %s", uri, destination)
 
 	client := grab.NewClient()
@@ -23,6 +26,9 @@ func Download(uri, destination string, mode os.FileMode) (string, error) {
 	if err != nil {
 		return "", errors.Wrapf(err, "unable to get response from %s", uri)
 	}
+	if sha256sum != nil {
+		req.SetChecksum(sha256.New(), sha256sum, true)
+	}
 
 	respCh := consoleClient.Do(context.Background(), 3, req)
 	resp := <-respCh

test/extended/util/util.go

@@ -117,7 +117,7 @@ func DownloadBundle(bundleLocation string, bundleDestination string, bundleName
 		return bundleDestination, err
 	}
 
-	filename, err := download.Download(bundleLocation, bundleDestination, 0644)
+	filename, err := download.Download(bundleLocation, bundleDestination, 0644, nil)
 	fmt.Printf("Downloading bundle from %s to %s.\n", bundleLocation, bundleDestination)
 	if err != nil {
 		return "", err