fix golint errors

pkg/loader/bundle/bundle.go

@@ -31,6 +31,7 @@ import (
 	"github.com/kubernetes-incubator/kompose/pkg/kobject"
 )
 
+// Bundle is docker bundle file loader, implements Loader interface
 type Bundle struct {
 }
 
@@ -172,7 +173,7 @@ func loadPorts(service Service) ([]kobject.Ports, string) {
 	return ports, ""
 }
 
-// load dab file into KomposeObject
+// LoadFile loads dab file into KomposeObject
 func (b *Bundle) LoadFile(files []string) kobject.KomposeObject {
 	komposeObject := kobject.KomposeObject{
 		ServiceConfigs: make(map[string]kobject.ServiceConfig),
@@ -244,7 +245,7 @@ func loadFile(reader io.Reader) (*Bundlefile, error) {
 				jsonErr.Error())
 		case *json.UnmarshalTypeError:
 			return nil, fmt.Errorf(
-				"Unexpected type at byte %v. Expected %s but received %s.",
+				"unexpected type at byte %v. expected %s but received %s",
 				jsonErr.Offset,
 				jsonErr.Type,
 				jsonErr.Value)

pkg/loader/compose/compose.go

@@ -34,6 +34,7 @@ import (
 	"github.com/kubernetes-incubator/kompose/pkg/kobject"
 )
 
+// Compose is docker compose file loader, implements Loader interface
 type Compose struct {
 }
 
@@ -220,7 +221,7 @@ func loadPorts(composePorts []string) ([]kobject.Ports, error) {
 	return ports, nil
 }
 
-// load compose file into KomposeObject
+// LoadFile loads compose file into KomposeObject
 func (c *Compose) LoadFile(files []string) kobject.KomposeObject {
 	komposeObject := kobject.KomposeObject{
 		ServiceConfigs: make(map[string]kobject.ServiceConfig),

pkg/loader/loader.go

@@ -17,7 +17,6 @@ limitations under the License.
 package loader
 
 import (
-	"errors"
 	"fmt"
 
 	"github.com/kubernetes-incubator/kompose/pkg/kobject"
@@ -25,6 +24,7 @@ import (
 	"github.com/kubernetes-incubator/kompose/pkg/loader/compose"
 )
 
+// Loader interface defines loader that loads files and converts it to kobject representation
 type Loader interface {
 	LoadFile(files []string) kobject.KomposeObject
 	///Name() string
@@ -40,7 +40,7 @@ func GetLoader(format string) (Loader, error) {
 	case "compose":
 		l = new(compose.Compose)
 	default:
-		return nil, errors.New(fmt.Sprintf("Input file format %s is not supported", format))
+		return nil, fmt.Errorf("Input file format %s is not supported", format)
 	}
 
 	return l, nil