try to clean up cache if updating grypeDB fails

Signed-off-by: Matthias Bertschy <matthias.bertschy@gmail.com>

adapters/v1/grype.go

@@ -2,6 +2,7 @@ package v1
 
 import (
 	"context"
+	"os"
 	"path"
 	"sync"
 	"time"
@@ -90,7 +91,11 @@ func (g *GrypeAdapter) Ready(ctx context.Context) bool {
 		g.store, g.dbStatus, g.dbCloser, err = grype.LoadVulnerabilityDB(g.dbConfig, true)
 		if err != nil {
 			logger.L().Ctx(ctx).Error("failed to update grype DB", helpers.Error(err))
-			return false
+			err := tools.DeleteContents(g.dbConfig.DBRootDir)
+			logger.L().Debug("cleaned up cache", helpers.Error(err),
+				helpers.String("DBRootDir", g.dbConfig.DBRootDir))
+			logger.L().Info("restarting to release previous grype DB")
+			os.Exit(0)
 		}
 		g.lastDbUpdate = now
 		logger.L().Info("grype DB updated")

internal/tools/tools.go

@@ -3,6 +3,7 @@ package tools
 import (
 	"encoding/json"
 	"os"
+	"path"
 	"regexp"
 	"runtime/debug"
 	"testing"
@@ -83,3 +84,17 @@ func FileToCVEManifest(path string) domain.CVEManifest {
 	}
 	return cve
 }
+
+func DeleteContents(dir string) error {
+	d, err := os.ReadDir(dir)
+	if err != nil {
+		return err
+	}
+	for _, c := range d {
+		err := os.RemoveAll(path.Join([]string{dir, c.Name()}...))
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}