Adding pluginv2 support for libnetwork (part 1)

Legacy plugins (aka pluginv1) calls in libnetwork are replaced with
calls using the new plugin model (aka pluginv2). pkg/plugins is still
used for managing the http client connections to the plugin.

This commit makes the necessary changes in docker/docker. Part 2 will
will take care of the libnetwork changes.

Signed-off-by: Anusha Ragunathan <anusha@docker.com>

daemon/daemon.go

@@ -623,11 +623,12 @@ func NewDaemon(config *Config, registryService registry.Service, containerdRemot
 		return nil, err
 	}
 
-	if err := d.restore(); err != nil {
+	// Plugin system initialization should happen before restore. Dont change order.
+	if err := pluginInit(d, config, containerdRemote); err != nil {
 		return nil, err
 	}
 
-	if err := pluginInit(d, config, containerdRemote); err != nil {
+	if err := d.restore(); err != nil {
 		return nil, err
 	}
 

plugin/manager.go

@@ -4,16 +4,13 @@ package plugin
 
 import (
 	"encoding/json"
-	"fmt"
 	"io"
 	"os"
 	"path/filepath"
-	"strings"
 	"sync"
 
 	"github.com/Sirupsen/logrus"
 	"github.com/docker/docker/libcontainerd"
-	"github.com/docker/docker/pkg/plugins"
 	"github.com/docker/docker/plugin/store"
 	"github.com/docker/docker/plugin/v2"
 	"github.com/docker/docker/registry"
@@ -21,12 +18,6 @@ import (
 
 var (
 	manager *Manager
-
-	/* allowV1PluginsFallback determines daemon's support for V1 plugins.
-	 * When the time comes to remove support for V1 plugins, flipping
-	 * this bool is all that will be needed.
-	 */
-	allowV1PluginsFallback = true
 )
 
 func (pm *Manager) restorePlugin(p *v2.Plugin) error {
@@ -45,7 +36,6 @@ type Manager struct {
 	libRoot           string
 	runRoot           string
 	pluginStore       *store.PluginStore
-	handlers          map[string]func(string, *plugins.Client)
 	containerdClient  libcontainerd.Client
 	registryService   registry.Service
 	liveRestore       bool
@@ -70,7 +60,6 @@ func Init(root string, remote libcontainerd.Remote, rs registry.Service, liveRes
 		libRoot:           root,
 		runRoot:           "/run/docker",
 		pluginStore:       store.NewPluginStore(root),
-		handlers:          make(map[string]func(string, *plugins.Client)),
 		registryService:   rs,
 		liveRestore:       liveRestore,
 		pluginEventLogger: evL,
@@ -88,16 +77,6 @@ func Init(root string, remote libcontainerd.Remote, rs registry.Service, liveRes
 	return nil
 }
 
-// Handle sets a callback for a given capability. The callback will be called for every plugin with a given capability.
-// TODO: append instead of set?
-func Handle(capability string, callback func(string, *plugins.Client)) {
-	pluginType := fmt.Sprintf("docker.%s/1", strings.ToLower(capability))
-	manager.handlers[pluginType] = callback
-	if allowV1PluginsFallback {
-		plugins.Handle(capability, callback)
-	}
-}
-
 // StateChanged updates plugin internals using libcontainerd events.
 func (pm *Manager) StateChanged(id string, e libcontainerd.StateInfo) error {
 	logrus.Debugf("plugin state changed %s %#v", id, e)

plugin/manager_linux.go

@@ -43,11 +43,7 @@ func (pm *Manager) enable(p *v2.Plugin, force bool) error {
 	}
 
 	pm.pluginStore.SetState(p, true)
-	for _, typ := range p.GetTypes() {
-		if handler := pm.handlers[typ.String()]; handler != nil {
-			handler(p.Name(), p.Client())
-		}
-	}
+	pm.pluginStore.CallHandler(p)
 
 	return nil
 }

plugin/store/store.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"path/filepath"
+	"strings"
 	"sync"
 
 	"github.com/Sirupsen/logrus"
@@ -32,7 +33,11 @@ func (name ErrNotFound) Error() string { return fmt.Sprintf("plugin %q not found
 // PluginStore manages the plugin inventory in memory and on-disk
 type PluginStore struct {
 	sync.RWMutex
-	plugins  map[string]*v2.Plugin
+	plugins map[string]*v2.Plugin
+	/* handlers are necessary for transition path of legacy plugins
+	 * to the new model. Legacy plugins use Handle() for registering an
+	 * activation callback.*/
+	handlers map[string]func(string, *plugins.Client)
 	nameToID map[string]string
 	plugindb string
 }
@@ -41,6 +46,7 @@ type PluginStore struct {
 func NewPluginStore(libRoot string) *PluginStore {
 	store = &PluginStore{
 		plugins:  make(map[string]*v2.Plugin),
+		handlers: make(map[string]func(string, *plugins.Client)),
 		nameToID: make(map[string]string),
 		plugindb: filepath.Join(libRoot, "plugins.json"),
 	}
@@ -222,3 +228,27 @@ func FindWithCapability(capability string) ([]CompatPlugin, error) {
 	}
 	return result, nil
 }
+
+// Handle sets a callback for a given capability. It is only used by network
+// and ipam drivers during plugin registration. The callback registers the
+// driver with the subsystem (network, ipam).
+func Handle(capability string, callback func(string, *plugins.Client)) {
+	pluginType := fmt.Sprintf("docker.%s/1", strings.ToLower(capability))
+
+	// Register callback with new plugin model.
+	store.handlers[pluginType] = callback
+
+	// Register callback with legacy plugin model.
+	if allowV1PluginsFallback {
+		plugins.Handle(capability, callback)
+	}
+}
+
+// CallHandler calls the registered callback. It is invoked during plugin enable.
+func (ps *PluginStore) CallHandler(p *v2.Plugin) {
+	for _, typ := range p.GetTypes() {
+		if handler := ps.handlers[typ.String()]; handler != nil {
+			handler(p.Name(), p.Client())
+		}
+	}
+}