(bug) Always overwrite local db when copying

Multiple runs of index add when --generate is specified because the
db file cannot be cleaned up. To account for this, update the
copyDatabaseTo function to not return when the parent folder already
exists and overwrite the actual database when doing io.Copy()

pkg/lib/indexer/indexer.go

@@ -71,7 +71,7 @@ func (i ImageIndexer) AddToIndex(request AddToIndexRequest) error {
 	// this is in its own function context so that the deferred cleanup runs before we do a docker build
 	// which prevents the full contents of the previous image from being in the build context
 	var databasePath string
-	if err := func () error {
+	if err := func() error {
 		tmpDir, err := ioutil.TempDir("./", tmpDirPrefix)
 		if err != nil {
 
@@ -152,7 +152,7 @@ func (i ImageIndexer) DeleteFromIndex(request DeleteFromIndexRequest) error {
 	// this is in its own function context so that the deferred cleanup runs before we do a docker build
 	// which prevents the full contents of the previous image from being in the build context
 	var databasePath string
-	if err := func () error {
+	if err := func() error {
 		tmpDir, err := ioutil.TempDir("./", tmpDirPrefix)
 		if err != nil {
 
@@ -228,7 +228,7 @@ func (i ImageIndexer) PruneFromIndex(request PruneFromIndexRequest) error {
 	// this is in its own function context so that the deferred cleanup runs before we do a docker build
 	// which prevents the full contents of the previous image from being in the build context
 	var databasePath string
-	if err := func () error {
+	if err := func() error {
 		tmpDir, err := ioutil.TempDir("./", tmpDirPrefix)
 		if err != nil {
 
@@ -339,8 +339,6 @@ func copyDatabaseTo(databaseFile, targetDir string) (string, error) {
 		if err := os.MkdirAll(targetDir, 0777); err != nil {
 			return "", err
 		}
-	} else {
-		return "", err
 	}
 
 	// Open the database file in the working dir
@@ -353,7 +351,7 @@ func copyDatabaseTo(databaseFile, targetDir string) (string, error) {
 	dbFile := path.Join(targetDir, defaultDatabaseFile)
 
 	// define the path to copy to the database/index.db file
-	to, err := os.OpenFile(dbFile, os.O_RDWR|os.O_CREATE, 0666)
+	to, err := os.OpenFile(dbFile, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0666)
 	if err != nil {
 		return "", err
 	}