Port over some work to make the system views a bit nicer

logical/framework/backend.go

@@ -68,6 +68,10 @@ type Backend struct {
 	// to the backend, if required.
 	Clean CleanupFunc
 
+	// Initialize is called after a backend is created. Storage should not be
+	// written to before this function is called.
+	Init InitializeFunc
+
 	// Invalidate is called when a keys is modified if required
 	Invalidate InvalidateFunc
 
@@ -95,6 +99,9 @@ type WALRollbackFunc func(*logical.Request, string, interface{}) error
 // CleanupFunc is the callback for backend unload.
 type CleanupFunc func()
 
+// InitializeFunc is the callback for backend creation.
+type InitializeFunc func() error
+
 // InvalidateFunc is the callback for backend key invalidation.
 type InvalidateFunc func(string)
 
@@ -231,6 +238,14 @@ func (b *Backend) Cleanup() {
 	}
 }
 
+func (b *Backend) Initialize() error {
+	if b.Init != nil {
+		return b.Init()
+	}
+
+	return nil
+}
+
 // InvalidateKey is used to clear caches and reset internal state on key changes
 func (b *Backend) InvalidateKey(key string) {
 	if b.Invalidate != nil {

logical/logical.go

@@ -39,6 +39,10 @@ type Backend interface {
 	// handle any cleanup like connection closing or releasing of file handles.
 	Cleanup()
 
+	// Initialize is invoked after a backend is created. It is the place to run
+	// any operations requiring storage; these should not be in the factory.
+	Initialize() error
+
 	// InvalidateKey may be invoked when an object is modified that belongs
 	// to the backend. The backend can use this to clear any caches or reset
 	// internal state as needed.
@@ -71,4 +75,27 @@ type Paths struct {
 
 	// Unauthenticated are the paths that can be accessed without any auth.
 	Unauthenticated []string
+
+	// LocalStorage are paths (prefixes) that are local to this instance; this
+	// indicates that these paths should not be replicated
+	LocalStorage []string
+}
+
+type ReplicationState uint32
+
+const (
+	ReplicationDisabled ReplicationState = iota
+	ReplicationPrimary
+	ReplicationSecondary
+)
+
+func (r ReplicationState) String() string {
+	switch r {
+	case ReplicationSecondary:
+		return "secondary"
+	case ReplicationPrimary:
+		return "primary"
+	}
+
+	return "disabled"
 }

logical/system_view.go

@@ -31,19 +31,18 @@ type SystemView interface {
 	// despite known slowdowns.
 	CachingDisabled() bool
 
-	// IsPrimary checks if this is a primary Vault instance. This
-	// can be used to avoid writes on secondaries and to avoid doing
-	// lazy upgrades which may cause writes.
-	IsPrimary() bool
+	// ReplicationState indicates the state of cluster replication
+	ReplicationState() ReplicationState
 }
 
 type StaticSystemView struct {
-	DefaultLeaseTTLVal time.Duration
-	MaxLeaseTTLVal     time.Duration
-	SudoPrivilegeVal   bool
-	TaintedVal         bool
-	CachingDisabledVal bool
-	Primary            bool
+	DefaultLeaseTTLVal  time.Duration
+	MaxLeaseTTLVal      time.Duration
+	SudoPrivilegeVal    bool
+	TaintedVal          bool
+	CachingDisabledVal  bool
+	Primary             bool
+	ReplicationStateVal ReplicationState
 }
 
 func (d StaticSystemView) DefaultLeaseTTL() time.Duration {
@@ -66,6 +65,6 @@ func (d StaticSystemView) CachingDisabled() bool {
 	return d.CachingDisabledVal
 }
 
-func (d StaticSystemView) IsPrimary() bool {
-	return d.Primary
+func (d StaticSystemView) ReplicationState() ReplicationState {
+	return d.ReplicationStateVal
 }

vault/core.go

@@ -299,6 +299,10 @@ type Core struct {
 	rpcClientConn *grpc.ClientConn
 	// The grpc forwarding client
 	rpcForwardingClient RequestForwardingClient
+
+	// replicationState keeps the current replication state cached for quick
+	// lookup
+	replicationState logical.ReplicationState
 }
 
 // CoreConfig is used to parameterize a core

vault/dynamic_system_view.go

@@ -6,14 +6,6 @@ import (
 	"github.com/hashicorp/vault/logical"
 )
 
-var (
-	sysViewIsPrimaryFunc = func(c *Core) func() bool {
-		return func() bool {
-			return true
-		}
-	}
-)
-
 type dynamicSystemView struct {
 	core       *Core
 	mountEntry *MountEntry
@@ -84,6 +76,10 @@ func (d dynamicSystemView) CachingDisabled() bool {
 }
 
 // Checks if this is a primary Vault instance.
-func (d dynamicSystemView) IsPrimary() bool {
-	return sysViewIsPrimaryFunc(d.core)()
+func (d dynamicSystemView) ReplicationState() logical.ReplicationState {
+	var state logical.ReplicationState
+	d.core.clusterParamsLock.RLock()
+	state = d.core.replicationState
+	d.core.clusterParamsLock.RUnlock()
+	return state
 }

vault/testing.go

@@ -387,6 +387,11 @@ func (n *rawHTTP) Cleanup() {
 	// noop
 }
 
+func (n *rawHTTP) Initialize() error {
+	// noop
+	return nil
+}
+
 func (n *rawHTTP) InvalidateKey(string) {
 	// noop
 }