Let MonitorHCPManager handle lifecycle instead of link controller

agent/consul/server.go

@@ -21,6 +21,11 @@ import (
 
 	"github.com/armon/go-metrics"
 	"github.com/fullstorydev/grpchan/inprocgrpc"
+	"go.etcd.io/bbolt"
+	"golang.org/x/time/rate"
+	"google.golang.org/grpc"
+
+	"github.com/hashicorp/consul-net-rpc/net/rpc"
 	"github.com/hashicorp/go-connlimit"
 	"github.com/hashicorp/go-hclog"
 	"github.com/hashicorp/go-memdb"
@@ -31,11 +36,6 @@ import (
 	walmetrics "github.com/hashicorp/raft-wal/metrics"
 	"github.com/hashicorp/raft-wal/verifier"
 	"github.com/hashicorp/serf/serf"
-	"go.etcd.io/bbolt"
-	"golang.org/x/time/rate"
-	"google.golang.org/grpc"
-
-	"github.com/hashicorp/consul-net-rpc/net/rpc"
 
 	"github.com/hashicorp/consul/acl"
 	"github.com/hashicorp/consul/agent/blockingquery"
@@ -53,6 +53,7 @@ import (
 	"github.com/hashicorp/consul/agent/consul/xdscapacity"
 	"github.com/hashicorp/consul/agent/grpc-external/services/peerstream"
 	"github.com/hashicorp/consul/agent/hcp"
+	"github.com/hashicorp/consul/agent/hcp/bootstrap"
 	hcpclient "github.com/hashicorp/consul/agent/hcp/client"
 	logdrop "github.com/hashicorp/consul/agent/log-drop"
 	"github.com/hashicorp/consul/agent/metadata"
@@ -889,6 +890,33 @@ func NewServer(config *Config, flat Deps, externalGRPCServer *grpc.Server,
 	// to enable RPC forwarding.
 	s.grpcLeaderForwarder = flat.LeaderForwarder
 
+	// Start watching HCP Link resource. This creates a channel that we can use to
+	// start and stop HCP manager when appropriate. This needs to be created after
+	// the GRPC services are set up in order for the resource service client to
+	// function. This uses the insecure grpc channel so that it doesn't need to
+	// present a valid ACL token.
+	//
+	// If this fails, HCP linking will not work, but to avoid crashing Consul, we log
+	// the error and continue on.
+	hcpLinkWatchCh, err := hcpctl.NewLinkWatch(
+		&lib.StopChannelContext{StopCh: shutdownCh},
+		logger.Named("hcp-link-watcher"),
+		pbresource.NewResourceServiceClient(s.insecureSafeGRPCChan),
+	)
+	if err != nil {
+		s.logger.Error("HCP Link watcher failed to start. HCP Link functionality is disabled", "error", err)
+	} else {
+		go hcp.MonitorHCPLink(
+			&lib.StopChannelContext{StopCh: shutdownCh},
+			logger.Named("hcp-link-watcher"),
+			s.hcpManager,
+			hcpLinkWatchCh,
+			hcpclient.NewClient,
+			bootstrap.LoadManagementToken,
+			flat.HCP.DataDir,
+		)
+	}
+
 	s.controllerManager = controller.NewManager(
 		// Usage of the insecure + unsafe grpc chan is required for the controller
 		// manager. It must be unauthorized so that controllers do not need to

internal/hcp/internal/controllers/link/controller.go

@@ -8,13 +8,13 @@ import (
 	"crypto/tls"
 	"strings"
 
-	gnmmod "github.com/hashicorp/hcp-sdk-go/clients/cloud-global-network-manager-service/preview/2022-02-15/models"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 	"google.golang.org/protobuf/types/known/anypb"
 
+	gnmmod "github.com/hashicorp/hcp-sdk-go/clients/cloud-global-network-manager-service/preview/2022-02-15/models"
+
 	"github.com/hashicorp/consul/agent/hcp"
-	"github.com/hashicorp/consul/agent/hcp/bootstrap"
 	hcpclient "github.com/hashicorp/consul/agent/hcp/client"
 	"github.com/hashicorp/consul/agent/hcp/config"
 	"github.com/hashicorp/consul/internal/controller"
@@ -54,16 +54,20 @@ func LinkController(
 		// on the leader.
 		// https://hashicorp.atlassian.net/browse/CC-7364
 		WithPlacement(controller.PlacementEachServer).
-		WithInitializer(&linkInitializer{
+		WithInitializer(
+			&linkInitializer{
 				cloudConfig: cfg,
-		}).
+			},
-		WithReconciler(&linkReconciler{
+		).
+		WithReconciler(
+			&linkReconciler{
 				resourceApisEnabled:    resourceApisEnabled,
 				hcpAllowV2ResourceApis: hcpAllowV2ResourceApis,
 				hcpClientFn:            hcpClientFn,
 				dataDir:                dataDir,
 				hcpManager:             hcpManager,
-		})
+			},
+		)
 }
 
 type linkReconciler struct {
@@ -178,43 +182,22 @@ func (r *linkReconciler) Reconcile(ctx context.Context, rt controller.Runtime, r
 			rt.Logger.Error("error marshalling link data", "error", err)
 			return err
 		}
-		_, err = rt.Client.Write(ctx, &pbresource.WriteRequest{Resource: &pbresource.Resource{
+		_, err = rt.Client.Write(
+			ctx, &pbresource.WriteRequest{Resource: &pbresource.Resource{
 				Id: &pbresource.ID{
 					Name: types.LinkName,
 					Type: pbhcp.LinkType,
 				},
 				Metadata: res.Metadata,
 				Data:     updatedData,
-		}})
+			}},
+		)
 		if err != nil {
 			rt.Logger.Error("error updating link", "error", err)
 			return err
 		}
 	}
 
-	// Load the management token if access is not set to read-only. Read-only clusters
-	// will not have a management token provided by HCP.
-	var token string
-	if accessLevel != pbhcp.AccessLevel_ACCESS_LEVEL_GLOBAL_READ_ONLY {
-		token, err = bootstrap.LoadManagementToken(ctx, rt.Logger, hcpClient, r.dataDir)
-		if err != nil {
-			linkingFailed(ctx, rt, res, err)
-			return err
-		}
-	}
-
-	// Update the HCP manager configuration with the link values
-	cfg.ManagementToken = token
-	r.hcpManager.UpdateConfig(hcpClient, cfg)
-
-	// Start the manager
-	err = r.hcpManager.Start(ctx)
-	if err != nil {
-		rt.Logger.Error("error starting HCP manager", "error", err)
-		linkingFailed(ctx, rt, res, err)
-		return err
-	}
-
 	newStatus = &pbresource.Status{
 		ObservedGeneration: res.Generation,
 		Conditions:         []*pbresource.Condition{ConditionLinked(link.ResourceId)},
@@ -233,17 +216,20 @@ func (i *linkInitializer) Initialize(ctx context.Context, rt controller.Runtime)
 	}
 
 	// Construct a link resource to reflect the configuration
-	data, err := anypb.New(&pbhcp.Link{
+	data, err := anypb.New(
+		&pbhcp.Link{
 			ResourceId:   i.cloudConfig.ResourceID,
 			ClientId:     i.cloudConfig.ClientID,
 			ClientSecret: i.cloudConfig.ClientSecret,
-	})
+		},
+	)
 	if err != nil {
 		return err
 	}
 
 	// Create the link resource for a configuration-based link
-	_, err = rt.Client.Write(ctx,
+	_, err = rt.Client.Write(
+		ctx,
 		&pbresource.WriteRequest{
 			Resource: &pbresource.Resource{
 				Id: &pbresource.ID{

internal/hcp/internal/controllers/link/finalizer.go

@@ -18,9 +18,6 @@ import (
 func cleanup(rt controller.Runtime, hcpManager hcp.Manager, dataDir string) error {
 	rt.Logger.Trace("cleaning up link resource")
 
-	rt.Logger.Debug("stopping HCP manager")
-	hcpManager.Stop()
-
 	if dataDir != "" {
 		hcpConfigDir := filepath.Join(dataDir, bootstrap.SubDir)
 		rt.Logger.Debug("deleting hcp-config dir", "dir", hcpConfigDir)