initial work to support dynamic cni configurations

Signed-off-by: Michael Zappa <michael.zappa@gmail.com>

Author: MikeZappa87

cni.go

@@ -35,8 +35,12 @@ type CNI interface {
 	Setup(ctx context.Context, id string, path string, opts ...NamespaceOpts) (*Result, error)
 	// SetupSerially sets up each of the network interfaces for the namespace in serial
 	SetupSerially(ctx context.Context, id string, path string, opts ...NamespaceOpts) (*Result, error)
+	//SetupNetworks sets up a list of networks
+	SetupNetworks(ctx context.Context, id string, path string, networks []*Network, opts ...NamespaceOpts) (*Result, error)
 	// Remove tears down the network of the namespace.
 	Remove(ctx context.Context, id string, path string, opts ...NamespaceOpts) error
+	// RemoveNetworks tears down a list of provided networks
+	RemoveNetworks(ctx context.Context, id string, path string, networks []*Network, opts ...NamespaceOpts) error
 	// Check checks if the network is still in desired state
 	Check(ctx context.Context, id string, path string, opts ...NamespaceOpts) error
 	// Load loads the cni network config
@@ -45,6 +49,8 @@ type CNI interface {
 	Status() error
 	// GetConfig returns a copy of the CNI plugin configurations as parsed by CNI
 	GetConfig() *ConfigResult
+	//BuildMultiNetwork returns a list of networks that match the network name in the cni cache
+	BuildMultiNetwork(networkNames []*NetworkInterface) []*Network
 }
 
 type ConfigResult struct {
@@ -83,6 +89,11 @@ type libcni struct {
 	sync.RWMutex
 }
 
+type NetworkInterface struct {
+	NetworkName   string
+	InterfaceName string
+}
+
 func defaultCNIConfig() *libcni {
 	return &libcni{
 		config: config{
@@ -183,15 +194,62 @@ func (c *libcni) SetupSerially(ctx context.Context, id string, path string, opts
 	return c.createResult(result)
 }
 
+// BuildMultiNetwork build dynamic list of Networks. Order Matters here!
+func (c *libcni) BuildMultiNetwork(networkNames []*NetworkInterface) []*Network {
+	var network []*Network
+	ifaceindex := 0
+	for _, net := range c.Networks() {
+		for _, x := range networkNames {
+			if net.config.Name == x.NetworkName {
+				if x.InterfaceName == "" {
+					net.ifName = getIfName(c.prefix, ifaceindex)
+				} else {
+					net.ifName = x.InterfaceName
+				}
+				//Doing this to ensure first selected cni conf ifname is eth0
+				if net.ifName != "lo" {
+					ifaceindex++
+				}
+
+				//TODO - Add logic to make sure interface collisions don't happen. However that could be an implementation detail.
+				network = append(network, net)
+			}
+		}
+	}
+
+	return network
+}
+
+// SetupSerially setups specific networks in the namespace and returns a Result
+func (c *libcni) SetupNetworks(ctx context.Context, id string, path string, networks []*Network, opts ...NamespaceOpts) (*Result, error) {
+	if err := c.Status(); err != nil {
+		return nil, err
+	}
+	ns, err := newNamespace(id, path, opts...)
+	if err != nil {
+		return nil, err
+	}
+	result, err := c.attachWithMultipleNetworksSerially(ctx, ns, networks)
+	if err != nil {
+		return nil, err
+	}
+	return c.createResult(result)
+}
+
 func (c *libcni) attachNetworksSerially(ctx context.Context, ns *Namespace) ([]*types100.Result, error) {
+	return c.attachWithMultipleNetworksSerially(ctx, ns, c.Networks())
+}
+
+func (c *libcni) attachWithMultipleNetworksSerially(ctx context.Context, ns *Namespace, networks []*Network) ([]*types100.Result, error) {
 	var results []*types100.Result
-	for _, network := range c.Networks() {
+	for _, network := range networks {
 		r, err := network.Attach(ctx, ns)
 		if err != nil {
 			return nil, err
 		}
 		results = append(results, r)
 	}
+
 	return results, nil
 }
 
@@ -258,6 +316,33 @@ func (c *libcni) Remove(ctx context.Context, id string, path string, opts ...Nam
 	return nil
 }
 
+func (c *libcni) RemoveNetworks(ctx context.Context, id string, path string, networks []*Network, opts ...NamespaceOpts) error {
+	if err := c.Status(); err != nil {
+		return err
+	}
+	ns, err := newNamespace(id, path, opts...)
+	if err != nil {
+		return err
+	}
+	for i := len(networks) - 1; i >= 0; i-- {
+		if err := networks[i].Remove(ctx, ns); err != nil {
+			// Based on CNI spec v0.7.0, empty network namespace is allowed to
+			// do best effort cleanup. However, it is not handled consistently
+			// right now:
+			// https://github.com/containernetworking/plugins/issues/210
+			// TODO(random-liu): Remove the error handling when the issue is
+			// fixed and the CNI spec v0.6.0 support is deprecated.
+			// NOTE(claudiub): Some CNIs could return a "not found" error, which could mean that
+			// it was already deleted.
+			if (path == "" && strings.Contains(err.Error(), "no such file or directory")) || strings.Contains(err.Error(), "not found") {
+				continue
+			}
+			return err
+		}
+	}
+	return nil
+}
+
 // Check checks if the network is still in desired state
 func (c *libcni) Check(ctx context.Context, id string, path string, opts ...NamespaceOpts) error {
 	if err := c.Status(); err != nil {

cni_test.go

@@ -285,6 +285,48 @@ func TestLibCNIType100(t *testing.T) {
 	assert.NoError(t, err)
 }
 
+func TestBuildNetworksWithAnnotation(t *testing.T) {
+	// Get the default CNI config
+	l := defaultCNIConfig()
+	// Create a fake cni config directory and file
+	cniDir, confDir := makeFakeCNIConfig(t)
+	defer tearDownCNIConfig(t, cniDir)
+	l.pluginConfDir = confDir
+	// Set the minimum network count as 2 for this test
+	l.networkCount = 2
+	err := l.Load(WithLoNetwork, WithAllConf)
+	assert.NoError(t, err)
+
+	err = l.Status()
+	assert.NoError(t, err)
+
+	net := []*NetworkInterface{
+		{
+			NetworkName:   "plugin2",
+			InterfaceName: "net1",
+		},
+		{
+			NetworkName:   "cni-loopback",
+			InterfaceName: "lo",
+		},
+		{
+			NetworkName: "plugin1",
+			//InterfaceName: "This should be commented out"
+		},
+	}
+
+	networks := l.BuildMultiNetwork(net)
+
+	assert.Equal(t, len(networks), 3)
+
+	assert.Equal(t, "lo", networks[0].ifName)
+	assert.Equal(t, "cni-loopback", networks[0].config.Name)
+	assert.Equal(t, "eth0", networks[1].ifName)
+	assert.Equal(t, "plugin1", networks[1].config.Name)
+	assert.Equal(t, "net1", networks[2].ifName)
+	assert.Equal(t, "plugin2", networks[2].config.Name)
+}
+
 type MockCNI struct {
 	mock.Mock
 }