txn: add node operations

agent/consul/state/catalog.go

@@ -373,6 +373,36 @@ func (s *Store) ensureNoNodeWithSimilarNameTxn(tx *memdb.Txn, node *structs.Node
 	return nil
 }
 
+// ensureNodeCASTxn updates a node only if the existing index matches the given index.
+// Returns a bool indicating if a write happened and any error.
+func (s *Store) ensureNodeCASTxn(tx *memdb.Txn, idx uint64, node *structs.Node) (bool, error) {
+	// Retrieve the existing entry.
+	existing, err := tx.First("nodes", "id", node.Node)
+	if err != nil {
+		return false, fmt.Errorf("node lookup failed: %s", err)
+	}
+
+	// Check if the we should do the set. A ModifyIndex of 0 means that
+	// we are doing a set-if-not-exists.
+	if node.ModifyIndex == 0 && existing != nil {
+		return false, nil
+	}
+	if node.ModifyIndex != 0 && existing == nil {
+		return false, nil
+	}
+	e, ok := existing.(*structs.Node)
+	if ok && node.ModifyIndex != 0 && node.ModifyIndex != e.ModifyIndex {
+		return false, nil
+	}
+
+	// Perform the update.
+	if err := s.ensureNodeTxn(tx, idx, node); err != nil {
+		return false, err
+	}
+
+	return true, nil
+}
+
 // ensureNodeTxn is the inner function called to actually create a node
 // registration or modify an existing one in the state store. It allows
 // passing in a memdb transaction so it may be part of a larger txn.
@@ -569,6 +599,35 @@ func (s *Store) DeleteNode(idx uint64, nodeName string) error {
 	return nil
 }
 
+// deleteNodeCASTxn is used to try doing a node delete operation with a given
+// raft index. If the CAS index specified is not equal to the last observed index for
+// the given check, then the call is a noop, otherwise a normal check delete is invoked.
+func (s *Store) deleteNodeCASTxn(tx *memdb.Txn, idx, cidx uint64, nodeName string) (bool, error) {
+	// Look up the node.
+	node, err := tx.First("nodes", "id", nodeName)
+	if err != nil {
+		return false, fmt.Errorf("check lookup failed: %s", err)
+	}
+	if node == nil {
+		return false, nil
+	}
+
+	// If the existing index does not match the provided CAS
+	// index arg, then we shouldn't update anything and can safely
+	// return early here.
+	existing, ok := node.(*structs.Node)
+	if !ok || existing.ModifyIndex != cidx {
+		return existing == nil, nil
+	}
+
+	// Call the actual deletion if the above passed.
+	if err := s.deleteNodeTxn(tx, idx, nodeName); err != nil {
+		return false, err
+	}
+
+	return true, nil
+}
+
 // deleteNodeTxn is the inner method used for removing a node from
 // the store within a given transaction.
 func (s *Store) deleteNodeTxn(tx *memdb.Txn, idx uint64, nodeName string) error {

agent/consul/state/txn.go

@@ -122,6 +122,59 @@ func (s *Store) txnIntention(tx *memdb.Txn, idx uint64, op *structs.TxnIntention
 	}
 }
 
+// txnNode handles all Node-related operations.
+func (s *Store) txnNode(tx *memdb.Txn, idx uint64, op *structs.TxnNodeOp) (structs.TxnResults, error) {
+	var entry *structs.Node
+	var err error
+
+	switch op.Verb {
+	case api.NodeGet:
+		entry, err = getNodeIDTxn(tx, op.Node.ID)
+
+	case api.NodeSet:
+		err = s.ensureNodeTxn(tx, idx, &op.Node)
+
+	case api.NodeCAS:
+		var ok bool
+		ok, err = s.ensureNodeCASTxn(tx, idx, &op.Node)
+		if !ok && err == nil {
+			err = fmt.Errorf("failed to set node %q, index is stale", op.Node.Node)
+		}
+
+	case api.NodeDelete:
+		err = s.deleteNodeTxn(tx, idx, op.Node.Node)
+
+	case api.NodeDeleteCAS:
+		var ok bool
+		ok, err = s.deleteNodeCASTxn(tx, idx, op.Node.ModifyIndex, op.Node.Node)
+		if !ok && err == nil {
+			err = fmt.Errorf("failed to delete node %q, index is stale", op.Node.Node)
+		}
+
+	default:
+		err = fmt.Errorf("unknown Node verb %q", op.Verb)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	// For a GET we keep the value, otherwise we clone and blank out the
+	// value (we have to clone so we don't modify the entry being used by
+	// the state store).
+	if entry != nil {
+		if op.Verb == api.NodeGet {
+			result := structs.TxnResult{Node: entry}
+			return structs.TxnResults{&result}, nil
+		}
+
+		clone := *entry
+		result := structs.TxnResult{Node: &clone}
+		return structs.TxnResults{&result}, nil
+	}
+
+	return nil, nil
+}
+
 // txnCheck handles all Check-related operations.
 func (s *Store) txnCheck(tx *memdb.Txn, idx uint64, op *structs.TxnCheckOp) (structs.TxnResults, error) {
 	var entry *structs.HealthCheck

agent/structs/txn.go

@@ -19,6 +19,28 @@ type TxnKVOp struct {
 // inside a transaction.
 type TxnKVResult *DirEntry
 
+// TxnNodeOp is used to define a single operation on a node in the catalog inside
+// a transaction.
+type TxnNodeOp struct {
+	Verb api.NodeOp
+	Node Node
+}
+
+// TxnNodeResult is used to define the result of a single operation on a node
+// in the catalog inside a transaction.
+type TxnNodeResult *Node
+
+// TxnServiceOp is used to define a single operation on a service in the catalog inside
+// a transaction.
+type TxnServiceOp struct {
+	Verb    api.ServiceOp
+	Service NodeService
+}
+
+// TxnServiceResult is used to define the result of a single operation on a service
+// in the catalog inside a transaction.
+type TxnServiceResult *NodeService
+
 // TxnCheckOp is used to define a single operation on a health check inside a
 // transaction.
 type TxnCheckOp struct {
@@ -39,6 +61,8 @@ type TxnIntentionOp IntentionRequest
 type TxnOp struct {
 	KV        *TxnKVOp
 	Intention *TxnIntentionOp
+	Node      *TxnNodeOp
+	Service   *TxnServiceOp
 	Check     *TxnCheckOp
 }
 
@@ -87,8 +111,10 @@ type TxnErrors []*TxnError
 // TxnResult is used to define the result of a given operation inside a
 // transaction. Only one of the types should be filled out per entry.
 type TxnResult struct {
-	KV    TxnKVResult
-	Check TxnCheckResult
+	KV      TxnKVResult
+	Node    TxnNodeResult
+	Service TxnServiceResult
+	Check   TxnCheckResult
 }
 
 // TxnResults is a list of TxnResult entries.

api/txn.go

@@ -89,6 +89,28 @@ type KVTxnResponse struct {
 	Errors  TxnErrors
 }
 
+// NodeOp constants give possible operations available in a transaction.
+type NodeOp string
+
+const (
+	NodeGet       NodeOp = "get"
+	NodeSet       NodeOp = "set"
+	NodeCAS       NodeOp = "cas"
+	NodeDelete    NodeOp = "delete"
+	NodeDeleteCAS NodeOp = "delete-cas"
+)
+
+// ServiceOp constants give possible operations available in a transaction.
+type ServiceOp string
+
+const (
+	ServiceGet       ServiceOp = "get"
+	ServiceSet       ServiceOp = "set"
+	ServiceCAS       ServiceOp = "cas"
+	ServiceDelete    ServiceOp = "delete"
+	ServiceDeleteCAS ServiceOp = "delete-cas"
+)
+
 // CheckOp constants give possible operations available in a transaction.
 type CheckOp string