generate: Don't serialize Spec.Linux as an empty JSON object

wking · wking · commit f2107e5bae23 · 2016-07-26T11:42:37.000-07:00
The "does the marshaled JSON look like '{}'?" check is a pretty cheap
trick, but it was the easiest way I could think of for "is there
anything useful in here?".

Signed-off-by: W. Trevor King &lt;wking@tremily.us&gt;
diff --git a/generate/generate.go b/generate/generate.go
@@ -181,6 +181,16 @@ func (g *Generator) GetSpec() *rspec.Spec {
 
 // Save writes the spec into w.
 func (g *Generator) Save(w io.Writer) error {
+	if g.spec.Linux != nil {
+		buf, err := json.Marshal(g.spec.Linux)
+		if err != nil {
+			return err
+		}
+		if string(buf) == "{}" {
+			g.spec.Linux = nil
+		}
+	}
+
 	data, err := json.MarshalIndent(g.spec, "", "\t")
 	if err != nil {
 		return err
@@ -959,6 +969,9 @@ func (g *Generator) SetupPrivileged(privileged bool) {
 		g.spec.Process.Capabilities = finalCapList
 		g.spec.Process.SelinuxLabel = ""
 		g.spec.Process.ApparmorProfile = ""
+		if g.spec.Linux == nil {
+			g.spec.Linux = &rspec.Linux{}
+		}
 		g.spec.Linux.Seccomp = nil
 	}
 }
