basic root dir pre check on fs storage.New (#199)

* basic root dir pre check on fs storage.New

* update uses of fs.storage.New to check for error

* use testify to check for error

cmd/olympus/actions/storage.go

@@ -23,7 +23,10 @@ func GetStorage() (storage.BackendConnector, error) {
 		if err != nil {
 			return nil, fmt.Errorf("missing disk storage root (%s)", err)
 		}
-		s := fs.NewStorage(rootLocation, afero.NewOsFs())
+		s, err := fs.NewStorage(rootLocation, afero.NewOsFs())
+		if err != nil {
+			return nil, fmt.Errorf("could not create new storage from os fs (%s)", err)
+		}
 		return storage.NoOpBackendConnector(s), nil
 	case "mongo":
 		mongoURI, err := envy.MustGet("ATHENS_MONGO_STORAGE_URL")

cmd/proxy/actions/storage.go

@@ -35,7 +35,10 @@ func GetStorage() (storage.BackendConnector, error) {
 		if err != nil {
 			return nil, fmt.Errorf("missing disk storage root (%s)", err)
 		}
-		s := fs.NewStorage(storageRoot, afero.NewOsFs())
+		s, err := fs.NewStorage(storageRoot, afero.NewOsFs())
+		if err != nil {
+			return nil, fmt.Errorf("could not create new storage from os fs (%s)", err)
+		}
 		return storage.NoOpBackendConnector(s), nil
 	case "postgres", "sqlite", "cockroach", "mysql":
 		storageRoot, err = envy.MustGet("ATHENS_RDBMS_STORAGE_NAME")

pkg/storage/fs/all_test.go

@@ -37,7 +37,8 @@ func (d *FsTests) SetupTest() {
 	memFs := afero.NewOsFs()
 	r, err := afero.TempDir(memFs, "", "athens-fs-tests")
 	d.Require().NoError(err)
-	d.storage = NewStorage(r, memFs)
+	d.storage, err = NewStorage(r, memFs)
+	d.Require().NoError(err)
 	d.rootDir = r
 	d.fs = memFs
 }

pkg/storage/fs/fs.go

@@ -1,6 +1,7 @@
 package fs
 
 import (
+	"fmt"
 	"path/filepath"
 
 	"github.com/gomods/athens/pkg/storage"
@@ -23,7 +24,15 @@ func (s *storageImpl) versionLocation(module, version string) string {
 
 // NewStorage returns a new ListerSaver implementation that stores
 // everything under rootDir
-func NewStorage(rootDir string, filesystem afero.Fs) storage.Backend {
-	return &storageImpl{rootDir: rootDir, filesystem: filesystem}
+// If the root directory does not exist an error is returned
+func NewStorage(rootDir string, filesystem afero.Fs) (storage.Backend, error) {
+	exists, err := afero.Exists(filesystem, rootDir)
+	if err != nil {
+		return nil, fmt.Errorf("could not check if root directory `%s` exists: %s", rootDir, err)
+	}
+	if !exists {
+		return nil, fmt.Errorf("root directory `%s` does not exist", rootDir)
+	}
+	return &storageImpl{rootDir: rootDir, filesystem: filesystem}, nil
 
 }

pkg/storage/mem/mem.go

@@ -29,7 +29,10 @@ func NewStorage() (storage.BackendConnector, error) {
 		return nil, fmt.Errorf("could not create temp dir for 'In Memory' storage (%s)", err)
 	}
 
-	s := fs.NewStorage(tmpDir, memFs)
+	s, err := fs.NewStorage(tmpDir, memFs)
+	if err != nil {
+		return nil, fmt.Errorf("could not create storage from memory fs (%s)", err)
+	}
 	memStorage = storage.NoOpBackendConnector(s)
 	return memStorage, nil
 }