refactor network name in kyaml container

kyaml/fn/runtime/container/container.go

@@ -161,15 +161,10 @@ func (c *Filter) getCommand() (string, []string) {
 	// run the container using docker.  this is simpler than using the docker
 	// libraries, and ensures things like auth work the same as if the container
 	// was run from the cli.
-
-	network := "none"
-	if c.Network.Name != "" {
-		network = c.Network.Name
-	}
 	args := []string{"run",
 		"--rm",                                              // delete the container afterward
 		"-i", "-a", "STDIN", "-a", "STDOUT", "-a", "STDERR", // attach stdin, stdout, stderr
-		"--network", network,
+		"--network", c.ContainerSpec.Network.Name.String(),
 
 		// added security options
 		"--user", c.User.String(),
@@ -198,3 +193,19 @@ func (c *Filter) getCommand() (string, []string) {
 	a := append(args, c.Image)
 	return "docker", a
 }
+
+// NewContainer returns a new container instance
+func NewContainer(spec runtimeutil.ContainerSpec) Filter {
+	f := Filter{ContainerSpec: spec}
+	// default user is nobody
+	if f.ContainerSpec.User.IsEmpty() {
+		f.ContainerSpec.User = runtimeutil.UserNobody
+	}
+
+	// default network name is none
+	if f.ContainerSpec.Network.Name.IsEmpty() {
+		f.ContainerSpec.Network.Name = runtimeutil.NetworkNameNone
+	}
+
+	return f
+}

kyaml/fn/runtime/container/container_test.go

@@ -38,12 +38,12 @@ metadata:
 				"--user", "nobody",
 				"--security-opt=no-new-privileges",
 			},
-			instance: Filter{
-				ContainerSpec: runtimeutil.ContainerSpec{
+			instance: NewContainer(
+				runtimeutil.ContainerSpec{
 					Image: "example.com:version",
 					User:  "nobody",
 				},
-			},
+			),
 		},
 
 		{
@@ -61,15 +61,15 @@ metadata:
 				"--user", "nobody",
 				"--security-opt=no-new-privileges",
 			},
-			instance: Filter{
-				ContainerSpec: runtimeutil.ContainerSpec{
+			instance: NewContainer(
+				runtimeutil.ContainerSpec{
 					Image: "example.com:version",
 					Network: runtimeutil.ContainerNetwork{
 						Name: "test-1",
 					},
 					User: "nobody",
 				},
-			},
+			),
 		},
 
 		{
@@ -91,8 +91,8 @@ metadata:
 				"--mount", fmt.Sprintf("type=%s,source=%s,target=%s,readonly", "volume", "myvol", "/local/"),
 				"--mount", fmt.Sprintf("type=%s,source=%s,target=%s,readonly", "tmpfs", "", "/local/"),
 			},
-			instance: Filter{
-				ContainerSpec: runtimeutil.ContainerSpec{
+			instance: NewContainer(
+				runtimeutil.ContainerSpec{
 					Image: "example.com:version",
 					StorageMounts: []runtimeutil.StorageMount{
 						{MountType: "bind", Src: "/mount/path", DstPath: "/local/"},
@@ -102,7 +102,7 @@ metadata:
 					},
 					User: "nobody",
 				},
-			},
+			),
 		},
 		{
 			name: "root user",
@@ -119,12 +119,12 @@ metadata:
 				"--user", "root",
 				"--security-opt=no-new-privileges",
 			},
-			instance: Filter{
-				ContainerSpec: runtimeutil.ContainerSpec{
+			instance: NewContainer(
+				runtimeutil.ContainerSpec{
 					Image: "example.com:version",
 					User:  "root",
 				},
-			},
+			),
 		},
 	}
 

kyaml/fn/runtime/runtimeutil/functiontypes.go

@@ -33,6 +33,26 @@ const (
 	UserNobody ContainerUser = "nobody"
 )
 
+// ContainerNetworkName is a type for network name used in container
+type ContainerNetworkName string
+
+func (n *ContainerNetworkName) String() string {
+	return string(*n)
+}
+
+func (n *ContainerNetworkName) IsEmpty() bool {
+	return string(*n) == ""
+}
+
+func (n *ContainerNetworkName) Set(s string) {
+	*n = ContainerNetworkName(s)
+}
+
+const (
+	NetworkNameNone  ContainerNetworkName = "none"
+	NetworkNameEmpty ContainerNetworkName = ""
+)
+
 // FunctionSpec defines a spec for running a function
 type FunctionSpec struct {
 	DeferFailure bool `json:"deferFailure,omitempty" yaml:"deferFailure,omitempty"`
@@ -75,7 +95,7 @@ type ContainerNetwork struct {
 	Required bool `json:"required,omitempty" yaml:"required,omitempty"`
 
 	// Name is the name of the network to use from a container
-	Name string `json:"name,omitempty" yaml:"name,omitempty"`
+	Name ContainerNetworkName `json:"name,omitempty" yaml:"name,omitempty"`
 }
 
 // StarlarkSpec defines how to run a function as a starlark program
@@ -128,7 +148,7 @@ func GetFunctionSpec(n *yaml.RNode) *FunctionSpec {
 	}
 
 	if fn := getFunctionSpecFromAnnotation(n, meta); fn != nil {
-		fn.Container.Network.Name = ""
+		fn.Container.Network.Name = NetworkNameEmpty
 		fn.StorageMounts = []StorageMount{}
 		return fn
 	}