cleanup: fix golint warnings in util, e2e

util: golint warns about exported methods to have a
comment or to unexport them.

e2e: golint warns about package comment to be of the form
"Package e2e ..."

Reported-by: https://goreportcard.com/report/github.com/ceph/ceph-csi

Updates: #975

Signed-off-by: Yug Gupta <ygupta@redhat.com>

e2e/log.go

@@ -10,6 +10,7 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
+
 package e2e
 
 import (

internal/util/credentials.go

@@ -33,6 +33,7 @@ const (
 	tmpKeyFileNamePrefix = "keyfile-"
 )
 
+// Credentials struct represents credentials to access the ceph cluster.
 type Credentials struct {
 	ID      string
 	KeyFile string
@@ -93,19 +94,23 @@ func newCredentialsFromSecret(idField, keyField string, secrets map[string]strin
 	return c, err
 }
 
+// DeleteCredentials removes the KeyFile.
 func (cr *Credentials) DeleteCredentials() {
 	// don't complain about unhandled error
 	_ = os.Remove(cr.KeyFile)
 }
 
+// NewUserCredentials creates new user credentials from secret.
 func NewUserCredentials(secrets map[string]string) (*Credentials, error) {
 	return newCredentialsFromSecret(credUserID, credUserKey, secrets)
 }
 
+// NewAdminCredentials creates new admin credentials from secret.
 func NewAdminCredentials(secrets map[string]string) (*Credentials, error) {
 	return newCredentialsFromSecret(credAdminID, credAdminKey, secrets)
 }
 
+// NewCredentials generates new credentials when id and key are provided.
 func NewCredentials(id, key string) (*Credentials, error) {
 	var c = &Credentials{}
 
@@ -118,6 +123,7 @@ func NewCredentials(id, key string) (*Credentials, error) {
 	return c, err
 }
 
+// GetMonValFromSecret returns monitors from secret.
 func GetMonValFromSecret(secrets map[string]string) (string, error) {
 	if mons, ok := secrets[credMonitors]; ok {
 		return mons, nil

internal/util/errors.go

@@ -57,6 +57,7 @@ func (e ErrSnapNameConflict) Error() string {
 	return e.err.Error()
 }
 
+// NewErrSnapNameConflict returns a ErrSnapNameConflict error when CSI snap name already exists.
 func NewErrSnapNameConflict(name string, err error) ErrSnapNameConflict {
 	return ErrSnapNameConflict{name, err}
 }

internal/util/idlocker.go

@@ -34,7 +34,7 @@ type VolumeLocks struct {
 	mux   sync.Mutex
 }
 
-// NewVolumeLocks returns new  VolumeLocks
+// NewVolumeLocks returns new VolumeLocks.
 func NewVolumeLocks() *VolumeLocks {
 	return &VolumeLocks{
 		locks: sets.NewString(),
@@ -53,6 +53,7 @@ func (vl *VolumeLocks) TryAcquire(volumeID string) bool {
 	return true
 }
 
+// Release deletes the lock on volumeID.
 func (vl *VolumeLocks) Release(volumeID string) {
 	vl.mux.Lock()
 	defer vl.mux.Unlock()