fix(network): allow inspecting pseudo networks

cmd/nerdctl/network/network_inspect_test.go

@@ -62,7 +62,6 @@ func TestNetworkInspectBasic(t *testing.T) {
 		},
 		{
 			Description: "none",
-			Require:     nerdtest.NerdctlNeedsFixing("no issue opened"),
 			Command:     test.Command("network", "inspect", "none"),
 			Expected: test.Expects(0, nil, func(stdout string, t tig.T) {
 				var dc []dockercompat.Network
@@ -74,7 +73,6 @@ func TestNetworkInspectBasic(t *testing.T) {
 		},
 		{
 			Description: "host",
-			Require:     nerdtest.NerdctlNeedsFixing("no issue opened"),
 			Command:     test.Command("network", "inspect", "host"),
 			Expected: test.Expects(0, nil, func(stdout string, t tig.T) {
 				var dc []dockercompat.Network

pkg/netutil/cni_plugin.go

@@ -20,6 +20,14 @@ type CNIPlugin interface {
 	GetPluginType() string
 }
 
+type pseudoNetworkPlugin struct {
+	PluginType string `json:"type"`
+}
+
+func (p *pseudoNetworkPlugin) GetPluginType() string {
+	return p.PluginType
+}
+
 type IPAMRange struct {
 	Subnet     string `json:"subnet"`
 	RangeStart string `json:"rangeStart,omitempty"`

pkg/netutil/netutil.go

@@ -60,8 +60,17 @@ func (e *CNIEnv) ListNetworksMatch(reqs []string, allowPseudoNetwork bool) (list
 
 	list = make(map[string][]*NetworkConfig)
 	for _, req := range reqs {
-		if !allowPseudoNetwork && (req == "host" || req == "none") {
-			errs = append(errs, fmt.Errorf("pseudo network not allowed: %s", req))
+		if req == "host" || req == "none" {
+			if !allowPseudoNetwork {
+				errs = append(errs, fmt.Errorf("pseudo network not allowed: %s", req))
+				continue
+			}
+			cfg, err := newPseudoNetworkConfig(req)
+			if err != nil {
+				errs = append(errs, err)
+				continue
+			}
+			list[req] = []*NetworkConfig{cfg}
 			continue
 		}
 
@@ -88,6 +97,30 @@ func (e *CNIEnv) ListNetworksMatch(reqs []string, allowPseudoNetwork bool) (list
 	return list, errs
 }
 
+func newPseudoNetworkConfig(name string) (*NetworkConfig, error) {
+	confJSON, err := json.Marshal(&cniNetworkConfig{
+		CNIVersion: "1.0.0",
+		Name:       name,
+		// Pseudo networks are not backed by real CNI config files. We still need a
+		// parseable config object so network inspect can render them consistently.
+		Plugins: []CNIPlugin{
+			&pseudoNetworkPlugin{PluginType: "nerdctl-pseudo"},
+		},
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	confList, err := libcni.ConfListFromBytes(confJSON)
+	if err != nil {
+		return nil, err
+	}
+
+	return &NetworkConfig{
+		NetworkConfigList: confList,
+	}, nil
+}
+
 func UsedNetworks(ctx context.Context, client *containerd.Client) (map[string][]string, error) {
 	nsService := client.NamespaceService()
 	nsList, err := nsService.List(ctx)
@@ -288,8 +321,8 @@ type NetworkConfig struct {
 type cniNetworkConfig struct {
 	CNIVersion string            `json:"cniVersion"`
 	Name       string            `json:"name"`
-	ID         string            `json:"nerdctlID"`
-	Labels     map[string]string `json:"nerdctlLabels"`
+	ID         string            `json:"nerdctlID,omitempty"`
+	Labels     map[string]string `json:"nerdctlLabels,omitempty"`
 	Plugins    []CNIPlugin       `json:"plugins"`
 }
 

pkg/netutil/netutil_test.go

@@ -379,3 +379,33 @@ func TestFSExistsPropagatesStatError(t *testing.T) {
 	assert.Assert(t, !exists)
 	assert.Assert(t, err != nil)
 }
+
+func TestListNetworksMatchIncludesPseudoNetworks(t *testing.T) {
+	cniConfTestDir := t.TempDir()
+	cniEnv := CNIEnv{
+		Path:        t.TempDir(),
+		NetconfPath: cniConfTestDir,
+	}
+
+	values := map[string]string{
+		"network_name": "regular-network",
+		"subnet":       "10.7.1.0/24",
+		"gateway":      "10.7.1.1",
+	}
+	tpl, err := template.New("test").Parse(preExistingNetworkConfigTemplate)
+	assert.NilError(t, err)
+	buf := &bytes.Buffer{}
+	assert.NilError(t, tpl.ExecuteTemplate(buf, "test", values))
+
+	testConfFile := filepath.Join(cniConfTestDir, fmt.Sprintf("%s.conf", testutil.Identifier(t)))
+	assert.NilError(t, filesystem.WriteFile(testConfFile, buf.Bytes(), 0600))
+
+	matches, errs := cniEnv.ListNetworksMatch([]string{"host", "none", "regular-network"}, true)
+	assert.Assert(t, len(errs) == 0)
+	assert.Equal(t, len(matches["host"]), 1)
+	assert.Equal(t, matches["host"][0].Name, "host")
+	assert.Equal(t, len(matches["none"]), 1)
+	assert.Equal(t, matches["none"][0].Name, "none")
+	assert.Equal(t, len(matches["regular-network"]), 1)
+	assert.Equal(t, matches["regular-network"][0].Name, "regular-network")
+}