fix: bugs for skaffold.yaml files read in via stdin

Author: aaron-prindle

pkg/skaffold/parser/config.go

@@ -107,7 +107,7 @@ func getConfigs(ctx context.Context, cfgOpts configOpts, opts config.SkaffoldOpt
 		return nil, sErrors.ConfigParsingError(err)
 	}
 
-	if !util.IsURL(cfgOpts.file) && !filepath.IsAbs(cfgOpts.file) {
+	if !util.IsURL(cfgOpts.file) && !filepath.IsAbs(cfgOpts.file) && cfgOpts.file != "-" {
 		cwd, _ := util.RealWorkDir()
 		// convert `file` path to absolute value as it's used as a map key in several places.
 		cfgOpts.file = filepath.Join(cwd, cfgOpts.file)

pkg/skaffold/util/config.go

@@ -25,14 +25,23 @@ import (
 	"github.com/GoogleContainerTools/skaffold/pkg/skaffold/output/log"
 )
 
+var stdin []byte
+
 // ReadConfiguration reads a `skaffold.yaml` configuration and
 // returns its content.
 func ReadConfiguration(filename string) ([]byte, error) {
 	switch {
 	case filename == "":
 		return nil, errors.New("filename not specified")
 	case filename == "-":
-		return ioutil.ReadAll(os.Stdin)
+		if len(stdin) == 0 {
+			var err error
+			stdin, err = ioutil.ReadAll(os.Stdin)
+			if err != nil {
+				return []byte{}, err
+			}
+		}
+		return stdin, nil
 	case IsURL(filename):
 		return Download(filename)
 	default: