play kube: fix args/command handling

when neither yaml.Args nor yaml.Command are specified, we should use the entrypoint and cmd from the image.

update the tests to cover this and another case (both args and command are specified).
use the registry image instead of redis, as it has both an entrypoint and command specified.
update the documentation around this handling to hopefully prevent regressions and confusion.

Signed-off-by: Peter Hunt <pehunt@redhat.com>

1 files changed, 16 insertions, 4 deletions

diff --git a/pkg/specgen/generate/kube/kube.go b/pkg/specgen/generate/kube/kube.go
index 5cc7891ac..c64fe76a6 100644
--- a/pkg/specgen/generate/kube/kube.go
+++ b/pkg/specgen/generate/kube/kube.go
@@ -112,11 +112,18 @@ func ToSpecGen(ctx context.Context, containerYAML v1.Container, iid string, newI
 		return nil, err
 	}
 	s.WorkDir = "/"
+	// We will use "Docker field name" internally here to avoid confusion
+	// and reference the "Kubernetes field name" when referencing the YAML
+	// ref: https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/#notes
+	entrypoint := []string{}
+	cmd := []string{}
 	if imageData != nil && imageData.Config != nil {
 		if imageData.Config.WorkingDir != "" {
 			s.WorkDir = imageData.Config.WorkingDir
 		}
-		s.Command = imageData.Config.Entrypoint
+		// Pull entrypoint and cmd from image
+		entrypoint = imageData.Config.Entrypoint
+		cmd = imageData.Config.Cmd
 		s.Labels = imageData.Config.Labels
 		if len(imageData.Config.StopSignal) > 0 {
 			stopSignal, err := util.ParseSignal(imageData.Config.StopSignal)
@@ -126,13 +133,18 @@ func ToSpecGen(ctx context.Context, containerYAML v1.Container, iid string, newI
 			s.StopSignal = &stopSignal
 		}
 	}
+	// If only the yaml.Command is specified, set it as the entrypoint and drop the image Cmd
 	if len(containerYAML.Command) != 0 {
-		s.Command = containerYAML.Command
+		entrypoint = containerYAML.Command
+		cmd = []string{}
 	}
-	// doc https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/#notes
+	// Only override the cmd field if yaml.Args is specified
+	// Keep the image entrypoint, or the yaml.command if specified
 	if len(containerYAML.Args) != 0 {
-		s.Command = append(s.Command, containerYAML.Args...)
+		cmd = containerYAML.Args
 	}
+
+	s.Command = append(entrypoint, cmd...)
 	// FIXME,
 	// we are currently ignoring imageData.Config.ExposedPorts
 	if containerYAML.WorkingDir != "" {