Merge pull request #3210 from corhere/network-allocator-controlapi-hooks

Afford NetworkAllocator passing per-app state in Control API responses

Author: dperny

api/api.pb.txt

@@ -7215,6 +7215,14 @@ file {
       type: TYPE_BOOL
       json_name: "pendingDelete"
     }
+    field {
+      name: "extra"
+      number: 7
+      label: LABEL_OPTIONAL
+      type: TYPE_MESSAGE
+      type_name: ".google.protobuf.Any"
+      json_name: "extra"
+    }
     options {
       70001 {
         1 {

api/objects.pb.go

@@ -332,6 +332,11 @@ message Network {
 	// the services that still use this service, and proceed to delete
 	// this network when all of these services are gone
 	bool pending_delete = 6;
+
+	// Extra encodes application-specific information about the live state
+	// of the network. The syntax and semantics of the value are dictated by
+	// the network allocator implementation.
+	google.protobuf.Any extra = 7;
 }
 
 // Cluster provides global cluster settings.

api/objects.proto

@@ -1524,6 +1524,10 @@ func (a *Allocator) procTasksNetwork(ctx context.Context, onRetry bool) {
 	}
 }
 
+func (a *Allocator) NetworkAllocator() networkallocator.NetworkAllocator {
+	return a.nwkAllocator
+}
+
 // updateTaskStatus sets TaskStatus and updates timestamp.
 func updateTaskStatus(t *api.Task, newStatus api.TaskState, message string) {
 	t.Status = api.TaskStatus{

manager/allocator/network.go

@@ -1,6 +1,8 @@
 package networkallocator
 
 import (
+	"context"
+
 	"github.com/moby/swarmkit/v2/api"
 )
 
@@ -87,6 +89,23 @@ type NetworkAllocator interface {
 	IsAttachmentAllocated(node *api.Node, networkAttachment *api.NetworkAttachment) bool
 }
 
+// OnGetNetworker is an optional interface that [NetworkAllocator] may implement
+// to customize the Control API response for GetNetwork and ListNetworks requests.
+type OnGetNetworker interface {
+	// OnGetNetwork is called with a copy of the network object that will be
+	// returned in a GetNetwork or ListNetworks Control API response. Any
+	// modifications to the network object will be reflected in the
+	// response. The modified network object will not be persisted to the
+	// store. Errors returned will be bubbled up to the Control API client.
+	//
+	// The network may not have been allocated at the time of the call.
+	// Calling OnGetNetwork with an unallocated network should not be an
+	// error.
+	//
+	// This method may be called concurrently from multiple goroutines.
+	OnGetNetwork(context.Context, *api.Network) error
+}
+
 // Config is used to store network related cluster config in the Manager.
 type Config struct {
 	// DefaultAddrPool specifies default subnet pool for global scope networks

manager/allocator/networkallocator/networkallocator.go

@@ -0,0 +1,35 @@
+package manager
+
+import (
+	"context"
+
+	"github.com/moby/swarmkit/v2/api"
+	"github.com/moby/swarmkit/v2/manager/allocator/networkallocator"
+)
+
+func (m *Manager) networkAllocator() networkallocator.NetworkAllocator {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	if m.allocator == nil {
+		return nil
+	}
+	return m.allocator.NetworkAllocator()
+}
+
+func (m *Manager) OnGetNetwork(ctx context.Context, n *api.Network) error {
+	if nwh, ok := m.networkAllocator().(networkallocator.OnGetNetworker); ok {
+		return nwh.OnGetNetwork(ctx, n)
+	}
+	return nil
+}
+
+func (m *Manager) OnListNetworks(ctx context.Context, networks []*api.Network) error {
+	if nwh, ok := m.networkAllocator().(networkallocator.OnGetNetworker); ok {
+		for _, n := range networks {
+			if err := nwh.OnGetNetwork(ctx, n); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}

manager/apihooks.go

@@ -0,0 +1,24 @@
+package controlapi
+
+import (
+	"context"
+
+	"github.com/moby/swarmkit/v2/api"
+)
+
+// ViewResponseMutator provides callbacks which may modify the response objects
+// for Get or List Control API requests before they are sent to the client.
+type ViewResponseMutator interface {
+	OnGetNetwork(context.Context, *api.Network) error
+	OnListNetworks(context.Context, []*api.Network) error
+}
+
+type NoopViewResponseMutator struct{}
+
+func (NoopViewResponseMutator) OnGetNetwork(ctx context.Context, n *api.Network) error {
+	return nil
+}
+
+func (NoopViewResponseMutator) OnListNetworks(ctx context.Context, networks []*api.Network) error {
+	return nil
+}

manager/controlapi/apihooks.go

@@ -148,6 +148,9 @@ func (s *Server) GetNetwork(ctx context.Context, request *api.GetNetworkRequest)
 	if n == nil {
 		return nil, status.Errorf(codes.NotFound, "network %s not found", request.NetworkID)
 	}
+	if err := s.viewhooks.OnGetNetwork(ctx, n); err != nil {
+		return nil, err
+	}
 	return &api.GetNetworkResponse{
 		Network: n,
 	}, nil
@@ -292,6 +295,10 @@ func (s *Server) ListNetworks(ctx context.Context, request *api.ListNetworksRequ
 		)
 	}
 
+	if err := s.viewhooks.OnListNetworks(ctx, networks); err != nil {
+		return nil, err
+	}
+
 	return &api.ListNetworksResponse{
 		Networks: networks,
 	}, nil

manager/controlapi/network.go

@@ -20,19 +20,24 @@ type Server struct {
 	raft           *raft.Node
 	securityConfig *ca.SecurityConfig
 	netvalidator   networkallocator.DriverValidator
+	viewhooks      ViewResponseMutator
 	dr             *drivers.DriverProvider
 }
 
 // NewServer creates a Cluster API server.
-func NewServer(store *store.MemoryStore, raft *raft.Node, securityConfig *ca.SecurityConfig, nv networkallocator.DriverValidator, dr *drivers.DriverProvider) *Server {
+func NewServer(store *store.MemoryStore, raft *raft.Node, securityConfig *ca.SecurityConfig, nv networkallocator.DriverValidator, vrm ViewResponseMutator, dr *drivers.DriverProvider) *Server {
 	if nv == nil {
 		nv = networkallocator.InertProvider{}
 	}
+	if vrm == nil {
+		vrm = NoopViewResponseMutator{}
+	}
 	return &Server{
 		store:          store,
 		dr:             dr,
 		raft:           raft,
 		securityConfig: securityConfig,
 		netvalidator:   nv,
+		viewhooks:      vrm,
 	}
 }

manager/controlapi/server.go

@@ -47,7 +47,7 @@ func newTestServer(t *testing.T) *testServer {
 	ts.Store = store.NewMemoryStore(&stateutils.MockProposer{})
 	assert.NotNil(t, ts.Store)
 
-	ts.Server = NewServer(ts.Store, nil, securityConfig, nil, nil)
+	ts.Server = NewServer(ts.Store, nil, securityConfig, nil, nil, nil)
 	assert.NotNil(t, ts.Server)
 
 	temp, err := os.CreateTemp("", "test-socket")