move dependencies to vendor

vendor/github.com/docker/libcompose/lookup/file.go

@@ -0,0 +1,30 @@
+package lookup
+
+import (
+	"io/ioutil"
+	"path"
+	"strings"
+
+	"github.com/Sirupsen/logrus"
+)
+
+// FileConfigLookup is a "bare" structure that implements the project.ConfigLookup interface
+type FileConfigLookup struct {
+}
+
+// Lookup returns the content and the actual filename of the file that is "built" using the
+// specified file and relativeTo string. file and relativeTo are supposed to be file path.
+// If file starts with a slash ('/'), it tries to load it, otherwise it will build a
+// filename using the folder part of relativeTo joined with file.
+func (f *FileConfigLookup) Lookup(file, relativeTo string) ([]byte, string, error) {
+	if strings.HasPrefix(file, "/") {
+		logrus.Debugf("Reading file %s", file)
+		bytes, err := ioutil.ReadFile(file)
+		return bytes, file, err
+	}
+
+	fileName := path.Join(path.Dir(relativeTo), file)
+	logrus.Debugf("Reading file %s relative to %s", fileName, relativeTo)
+	bytes, err := ioutil.ReadFile(fileName)
+	return bytes, fileName, err
+}