stream: Use a no-op event publisher if streaming is disabled

agent/connect/ca/provider_consul_test.go

@@ -6,10 +6,11 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/require"
+
 	"github.com/hashicorp/consul/agent/connect"
 	"github.com/hashicorp/consul/agent/consul/state"
 	"github.com/hashicorp/consul/agent/structs"
-	"github.com/stretchr/testify/require"
 )
 
 type consulCAMockDelegate struct {
@@ -48,10 +49,7 @@ func (c *consulCAMockDelegate) ApplyCARequest(req *structs.CARequest) (interface
 }
 
 func newMockDelegate(t *testing.T, conf *structs.CAConfiguration) *consulCAMockDelegate {
-	s, err := state.NewStateStore(nil)
+	s := state.NewStateStore(nil)
-	if err != nil {
-		t.Fatalf("err: %s", err)
-	}
 	if s == nil {
 		t.Fatalf("missing state store")
 	}

agent/consul/fsm/fsm.go

@@ -6,13 +6,14 @@ import (
 	"sync"
 	"time"
 
-	"github.com/hashicorp/consul/agent/consul/state"
-	"github.com/hashicorp/consul/agent/structs"
-	"github.com/hashicorp/consul/logging"
 	"github.com/hashicorp/go-hclog"
 	"github.com/hashicorp/go-msgpack/codec"
 	"github.com/hashicorp/go-raftchunking"
 	"github.com/hashicorp/raft"
+
+	"github.com/hashicorp/consul/agent/consul/state"
+	"github.com/hashicorp/consul/agent/structs"
+	"github.com/hashicorp/consul/logging"
 )
 
 // command is a command method on the FSM.
@@ -41,7 +42,9 @@ func registerCommand(msg structs.MessageType, fn unboundCommand) {
 // along with Raft to provide strong consistency. We implement
 // this outside the Server to avoid exposing this outside the package.
 type FSM struct {
-	logger hclog.Logger
+	deps    Deps
+	logger  hclog.Logger
+	chunker *raftchunking.ChunkingFSM
 
 	// apply is built off the commands global and is used to route apply
 	// operations to their appropriate handlers.
@@ -53,28 +56,40 @@ type FSM struct {
 	// Raft side, so doesn't need to lock this.
 	stateLock sync.RWMutex
 	state     *state.Store
-
-	gc *state.TombstoneGC
-
-	chunker *raftchunking.ChunkingFSM
 }
 
 // New is used to construct a new FSM with a blank state.
+//
+// Deprecated: use NewFromDeps.
 func New(gc *state.TombstoneGC, logger hclog.Logger) (*FSM, error) {
-	if logger == nil {
+	newStateStore := func() *state.Store {
-		logger = hclog.New(&hclog.LoggerOptions{})
+		return state.NewStateStore(gc)
 	}
+	return NewFromDeps(Deps{Logger: logger, NewStateStore: newStateStore}), nil
+}
 
-	stateNew, err := state.NewStateStore(gc)
+// Deps are dependencies used to construct the FSM.
-	if err != nil {
+type Deps struct {
-		return nil, err
+	// Logger used to emit log messages
+	Logger hclog.Logger
+	// NewStateStore returns a state.Store which the FSM will use to make changes
+	// to the state.
+	// NewStateStore will be called once when the FSM is created and again any
+	// time Restore() is called.
+	NewStateStore func() *state.Store
+}
+
+// NewFromDeps creates a new FSM from its dependencies.
+func NewFromDeps(deps Deps) *FSM {
+	if deps.Logger == nil {
+		deps.Logger = hclog.New(&hclog.LoggerOptions{})
 	}
 
 	fsm := &FSM{
-		logger: logger.Named(logging.FSM),
+		deps:   deps,
+		logger: deps.Logger.Named(logging.FSM),
 		apply:  make(map[structs.MessageType]command),
-		state:  stateNew,
+		state:  deps.NewStateStore(),
-		gc:     gc,
 	}
 
 	// Build out the apply dispatch table based on the registered commands.
@@ -86,8 +101,7 @@ func New(gc *state.TombstoneGC, logger hclog.Logger) (*FSM, error) {
 	}
 
 	fsm.chunker = raftchunking.NewChunkingFSM(fsm, nil)
-
+	return fsm
-	return fsm, nil
 }
 
 func (c *FSM) ChunkingFSM() *raftchunking.ChunkingFSM {
@@ -149,11 +163,7 @@ func (c *FSM) Snapshot() (raft.FSMSnapshot, error) {
 func (c *FSM) Restore(old io.ReadCloser) error {
 	defer old.Close()
 
-	// Create a new state store.
+	stateNew := c.deps.NewStateStore()
-	stateNew, err := state.NewStateStore(c.gc)
-	if err != nil {
-		return err
-	}
 
 	// Set up a new restore transaction
 	restore := stateNew.Restore()

agent/consul/gateway_locator_test.go

@@ -5,18 +5,18 @@ import (
 	"testing"
 	"time"
 
+	memdb "github.com/hashicorp/go-memdb"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
 	"github.com/hashicorp/consul/agent/consul/state"
 	"github.com/hashicorp/consul/agent/structs"
 	"github.com/hashicorp/consul/api"
 	"github.com/hashicorp/consul/sdk/testutil"
-	memdb "github.com/hashicorp/go-memdb"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
 )
 
 func TestGatewayLocator(t *testing.T) {
-	state, err := state.NewStateStore(nil)
+	state := state.NewStateStore(nil)
-	require.NoError(t, err)
 
 	dc1 := &structs.FederationState{
 		Datacenter: "dc1",
@@ -362,10 +362,6 @@ func (d *testServerDelegate) blockingQuery(
 	return err
 }
 
-func newFakeStateStore() (*state.Store, error) {
-	return state.NewStateStore(nil)
-}
-
 func (d *testServerDelegate) IsLeader() bool {
 	return d.isLeader
 }

agent/consul/issue_test.go

@@ -4,11 +4,13 @@ import (
 	"reflect"
 	"testing"
 
+	"github.com/hashicorp/go-hclog"
+	"github.com/hashicorp/raft"
+
 	consulfsm "github.com/hashicorp/consul/agent/consul/fsm"
+	"github.com/hashicorp/consul/agent/consul/state"
 	"github.com/hashicorp/consul/agent/structs"
 	"github.com/hashicorp/consul/api"
-	"github.com/hashicorp/consul/sdk/testutil"
-	"github.com/hashicorp/raft"
 )
 
 func makeLog(buf []byte) *raft.Log {
@@ -23,11 +25,12 @@ func makeLog(buf []byte) *raft.Log {
 // Testing for GH-300 and GH-279
 func TestHealthCheckRace(t *testing.T) {
 	t.Parallel()
-	logger := testutil.Logger(t)
+	fsm := consulfsm.NewFromDeps(consulfsm.Deps{
-	fsm, err := consulfsm.New(nil, logger)
+		Logger: hclog.New(nil),
-	if err != nil {
+		NewStateStore: func() *state.Store {
-		t.Fatalf("err: %v", err)
+			return state.NewStateStore(nil)
-	}
+		},
+	})
 	state := fsm.State()
 
 	req := structs.RegisterRequest{

agent/consul/server.go

@@ -391,6 +391,7 @@ func NewServer(config *Config, flat Deps) (*Server, error) {
 		shutdownCh:              shutdownCh,
 		leaderRoutineManager:    NewLeaderRoutineManager(logger),
 		aclAuthMethodValidators: authmethod.NewCache(),
+		fsm:                     newFSMFromConfig(flat.Logger, gc, config),
 	}
 
 	if s.config.ConnectMeshGatewayWANFederationEnabled {
@@ -616,6 +617,21 @@ func NewServer(config *Config, flat Deps) (*Server, error) {
 	return s, nil
 }
 
+func newFSMFromConfig(logger hclog.Logger, gc *state.TombstoneGC, config *Config) *fsm.FSM {
+	deps := fsm.Deps{Logger: logger}
+	if config.RPCConfig.EnableStreaming {
+		deps.NewStateStore = func() *state.Store {
+			return state.NewStateStoreWithEventPublisher(gc)
+		}
+		return fsm.NewFromDeps(deps)
+	}
+
+	deps.NewStateStore = func() *state.Store {
+		return state.NewStateStore(gc)
+	}
+	return fsm.NewFromDeps(deps)
+}
+
 func newGRPCHandlerFromConfig(deps Deps, config *Config, s *Server) connHandler {
 	if !config.RPCConfig.EnableStreaming {
 		return agentgrpc.NoOpHandler{Logger: deps.Logger}
@@ -665,13 +681,6 @@ func (s *Server) setupRaft() error {
 		}
 	}()
 
-	// Create the FSM.
-	var err error
-	s.fsm, err = fsm.New(s.tombstoneGC, s.logger)
-	if err != nil {
-		return err
-	}
-
 	var serverAddressProvider raft.ServerAddressProvider = nil
 	if s.config.RaftConfig.ProtocolVersion >= 3 { //ServerAddressProvider needs server ids to work correctly, which is only supported in protocol version 3 or higher
 		serverAddressProvider = s.serverLookup
@@ -772,10 +781,12 @@ func (s *Server) setupRaft() error {
 				return fmt.Errorf("recovery failed to parse peers.json: %v", err)
 			}
 
-			tmpFsm, err := fsm.New(s.tombstoneGC, s.logger)
+			tmpFsm := fsm.NewFromDeps(fsm.Deps{
-			if err != nil {
+				Logger: s.logger,
-				return fmt.Errorf("recovery failed to make temp FSM: %v", err)
+				NewStateStore: func() *state.Store {
-			}
+					return state.NewStateStore(s.tombstoneGC)
+				},
+			})
 			if err := raft.RecoverCluster(s.config.RaftConfig, tmpFsm,
 				log, stable, snap, trans, configuration); err != nil {
 				return fmt.Errorf("recovery failed: %v", err)
@@ -817,11 +828,9 @@ func (s *Server) setupRaft() error {
 	s.raftNotifyCh = raftNotifyCh
 
 	// Setup the Raft store.
+	var err error
 	s.raft, err = raft.NewRaft(s.config.RaftConfig, s.fsm.ChunkingFSM(), log, stable, snap, trans)
-	if err != nil {
+	return err
-		return err
-	}
-	return nil
 }
 
 // endpointFactory is a function that returns an RPC endpoint bound to the given

agent/consul/state/catalog_test.go

@@ -7,14 +7,15 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/hashicorp/consul/agent/structs"
-	"github.com/hashicorp/consul/api"
-	"github.com/hashicorp/consul/lib/stringslice"
-	"github.com/hashicorp/consul/types"
 	"github.com/hashicorp/go-memdb"
 	uuid "github.com/hashicorp/go-uuid"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+
+	"github.com/hashicorp/consul/agent/structs"
+	"github.com/hashicorp/consul/api"
+	"github.com/hashicorp/consul/lib/stringslice"
+	"github.com/hashicorp/consul/types"
 )
 
 func makeRandomNodeID(t *testing.T) types.NodeID {
@@ -1080,10 +1081,7 @@ func TestStateStore_GetNodes(t *testing.T) {
 }
 
 func BenchmarkGetNodes(b *testing.B) {
-	s, err := NewStateStore(nil)
+	s := NewStateStore(nil)
-	if err != nil {
-		b.Fatalf("err: %s", err)
-	}
 
 	if err := s.EnsureNode(100, &structs.Node{Node: "foo", Address: "127.0.0.1"}); err != nil {
 		b.Fatalf("err: %v", err)
@@ -3710,10 +3708,7 @@ func TestStateStore_CheckConnectServiceNodes_Gateways(t *testing.T) {
 }
 
 func BenchmarkCheckServiceNodes(b *testing.B) {
-	s, err := NewStateStore(nil)
+	s := NewStateStore(nil)
-	if err != nil {
-		b.Fatalf("err: %s", err)
-	}
 
 	if err := s.EnsureNode(1, &structs.Node{Node: "foo", Address: "127.0.0.1"}); err != nil {
 		b.Fatalf("err: %v", err)

agent/consul/state/kvs_test.go

@@ -8,8 +8,9 @@ import (
 
 	"github.com/stretchr/testify/require"
 
-	"github.com/hashicorp/consul/agent/structs"
 	"github.com/hashicorp/go-memdb"
+
+	"github.com/hashicorp/consul/agent/structs"
 )
 
 func TestStateStore_ReapTombstones(t *testing.T) {
@@ -91,10 +92,7 @@ func TestStateStore_GC(t *testing.T) {
 
 	// Enable it and attach it to the state store.
 	gc.SetEnabled(true)
-	s, err := NewStateStore(gc)
+	s := NewStateStore(gc)
-	if err != nil {
-		t.Fatalf("err: %s", err)
-	}
 
 	// Create some KV pairs.
 	testSetKey(t, s, 1, "foo", "foo", nil)

agent/consul/state/memdb.go

@@ -1,6 +1,7 @@
 package state
 
 import (
+	"context"
 	"fmt"
 
 	"github.com/hashicorp/go-memdb"
@@ -51,10 +52,16 @@ type Changes struct {
 // 2. Sent to the eventPublisher which will create and emit change events
 type changeTrackerDB struct {
 	db             *memdb.MemDB
-	publisher      *stream.EventPublisher
+	publisher      EventPublisher
 	processChanges func(ReadTxn, Changes) ([]stream.Event, error)
 }
 
+type EventPublisher interface {
+	Publish([]stream.Event)
+	Run(context.Context)
+	Subscribe(*stream.SubscribeRequest) (*stream.Subscription, error)
+}
+
 // Txn exists to maintain backwards compatibility with memdb.DB.Txn. Preexisting
 // code may use it to create a read-only transaction, but it will panic if called
 // with write=true.

agent/consul/state/state_store.go

@@ -153,36 +153,46 @@ type sessionCheck struct {
 }
 
 // NewStateStore creates a new in-memory state storage layer.
-func NewStateStore(gc *TombstoneGC) (*Store, error) {
+func NewStateStore(gc *TombstoneGC) *Store {
 	// Create the in-memory DB.
 	schema := stateStoreSchema()
 	db, err := memdb.NewMemDB(schema)
 	if err != nil {
-		return nil, fmt.Errorf("Failed setting up state store: %s", err)
+		// the only way for NewMemDB to error is if the schema is invalid. The
+		// scheme is static and tested to be correct, so any failure here would
+		// be a programming error, which should panic.
+		panic(fmt.Sprintf("failed to create state store: %v", err))
 	}
-
-	pub := stream.NewEventPublisher(newSnapshotHandlers((*readDB)(db)), 10*time.Second)
-	ctx, cancel := context.WithCancel(context.TODO())
 	s := &Store{
 		schema:             schema,
 		abandonCh:          make(chan struct{}),
 		kvsGraveyard:       NewGraveyard(gc),
 		lockDelay:          NewDelay(),
-		stopEventPublisher: cancel,
+		stopEventPublisher: func() {},
 		db: &changeTrackerDB{
 			db:             db,
-			publisher:      pub,
+			publisher:      stream.NoOpEventPublisher{},
 			processChanges: processDBChanges,
 		},
 	}
+	return s
+}
+
+func NewStateStoreWithEventPublisher(gc *TombstoneGC) *Store {
+	store := NewStateStore(gc)
+	ctx, cancel := context.WithCancel(context.TODO())
+	store.stopEventPublisher = cancel
+
+	pub := stream.NewEventPublisher(newSnapshotHandlers((*readDB)(store.db.db)), 10*time.Second)
+	store.db.publisher = pub
 
 	go pub.Run(ctx)
-	return s, nil
+	return store
 }
 
 // EventPublisher returns the stream.EventPublisher used by the Store to
 // publish events.
-func (s *Store) EventPublisher() *stream.EventPublisher {
+func (s *Store) EventPublisher() EventPublisher {
 	return s.db.publisher
 }
 

agent/consul/state/state_store_test.go

@@ -6,10 +6,11 @@ import (
 	"testing"
 	"time"
 
-	"github.com/hashicorp/consul/agent/structs"
-	"github.com/hashicorp/consul/types"
 	"github.com/hashicorp/go-memdb"
 	"github.com/stretchr/testify/require"
+
+	"github.com/hashicorp/consul/agent/structs"
+	"github.com/hashicorp/consul/types"
 )
 
 func testUUID() string {
@@ -48,10 +49,7 @@ func restoreIndexes(indexes []*IndexEntry, r *Restore) error {
 }
 
 func testStateStore(t *testing.T) *Store {
-	s, err := NewStateStore(nil)
+	s := NewStateStore(nil)
-	if err != nil {
-		t.Fatalf("err: %s", err)
-	}
 	if s == nil {
 		t.Fatalf("missing state store")
 	}

agent/consul/stream/noop.go

@@ -0,0 +1,16 @@
+package stream
+
+import (
+	"context"
+	"fmt"
+)
+
+type NoOpEventPublisher struct{}
+
+func (NoOpEventPublisher) Publish([]Event) {}
+
+func (NoOpEventPublisher) Run(context.Context) {}
+
+func (NoOpEventPublisher) Subscribe(*SubscribeRequest) (*Subscription, error) {
+	return nil, fmt.Errorf("stream event publisher is disabled")
+}

agent/consul/usagemetrics/usagemetrics_oss_test.go

@@ -7,13 +7,14 @@ import (
 	"time"
 
 	"github.com/armon/go-metrics"
+	"github.com/stretchr/testify/require"
+
 	"github.com/hashicorp/consul/agent/consul/state"
 	"github.com/hashicorp/consul/agent/structs"
 	"github.com/hashicorp/consul/sdk/testutil"
-	"github.com/stretchr/testify/require"
 )
 
-func newStateStore() (*state.Store, error) {
+func newStateStore() *state.Store {
 	return state.NewStateStore(nil)
 }
 
@@ -91,8 +92,7 @@ func TestUsageReporter_emitServiceUsage_OSS(t *testing.T) {
 			metrics.NewGlobal(cfg, sink)
 
 			mockStateProvider := &mockStateProvider{}
-			s, err := newStateStore()
+			s := state.NewStateStore(nil)
-			require.NoError(t, err)
 			if tcase.modfiyStateStore != nil {
 				tcase.modfiyStateStore(t, s)
 			}

agent/consul/usagemetrics/usagemetrics_test.go

@@ -5,11 +5,12 @@ import (
 	"time"
 
 	"github.com/armon/go-metrics"
+	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/require"
+
 	"github.com/hashicorp/consul/agent/consul/state"
 	"github.com/hashicorp/consul/agent/structs"
 	"github.com/hashicorp/consul/sdk/testutil"
-	"github.com/stretchr/testify/mock"
-	"github.com/stretchr/testify/require"
 )
 
 type mockStateProvider struct {
@@ -61,8 +62,7 @@ func TestUsageReporter_Run_Nodes(t *testing.T) {
 			metrics.NewGlobal(cfg, sink)
 
 			mockStateProvider := &mockStateProvider{}
-			s, err := newStateStore()
+			s := newStateStore()
-			require.NoError(t, err)
 			if tcase.modfiyStateStore != nil {
 				tcase.modfiyStateStore(t, s)
 			}

agent/rpc/subscribe/subscribe_test.go

@@ -308,10 +308,7 @@ func newTestBackend() (*testBackend, error) {
 	if err != nil {
 		return nil, err
 	}
-	store, err := state.NewStateStore(gc)
+	store := state.NewStateStoreWithEventPublisher(gc)
-	if err != nil {
-		return nil, err
-	}
 	allowAll := func(_ string) acl.Authorizer {
 		return acl.AllowAll()
 	}