Refactors TxnRequest/TxnResponse into a form that will allow non-KV ops.

This isn't needed/used yet, but it's a good hook to get in there so we
can add more atomic operations in the future. The Go API hides this detail
so that feels like a KV-specific API. The implications on the REST API are
pretty minimal.

api/kv.go

@@ -41,7 +41,7 @@ const (
 
 // KVTxnOp defines a single operation inside a transaction.
 type KVTxnOp struct {
-	Op      string
+	Verb    string
 	Key     string
 	Value   []byte
 	Flags   uint64
@@ -49,23 +49,14 @@ type KVTxnOp struct {
 	Session string
 }
 
-// KVTxn defines a set of operations to be performed inside a single transaction.
+// KVTxnOps defines a set of operations to be performed inside a single
-type KVTxn []KVTxnOp
-
-// KVTxnError is used to return information about an operation in a
 // transaction.
-type KVTxnError struct {
+type KVTxnOps []*KVTxnOp
-	OpIndex int
-	What    string
-}
 
-// KVTxnErrors is a list of KVTxnError objects.
+// KVTxnResponse has the outcome of a transaction.
-type KVTxnErrors []KVTxnError
+type KVTxnResponse struct {
-
+	Results []*KVPair
-// KVTxnResult is used to return the results of a transaction.
+	Errors  TxnErrors
-type KVTxnResult struct {
-	Errors  KVTxnErrors
-	Results KVPairs
 }
 
 // KV is used to manipulate the K/V API
@@ -284,43 +275,84 @@ func (k *KV) deleteInternal(key string, params map[string]string, q *WriteOption
 	return res, qm, nil
 }
 
+// TxnOp is the internal format we send to Consul. It's not specific to KV,
+// though currently only KV operations are supported.
+type TxnOp struct {
+	KVS *KVTxnOp
+}
+
+// TxnOps is a list of transaction operations.
+type TxnOps []*TxnOp
+
+// TxnResult is the internal format we receive from Consul.
+type TxnResult struct {
+	KVS *struct{ DirEnt *KVPair }
+}
+
+// TxnResults is a list of TxnResult objects.
+type TxnResults []*TxnResult
+
+// TxnError is used to return information about an operation in a transaction.
+type TxnError struct {
+	OpIndex int
+	What    string
+}
+
+// TxnErrors is a list of TxnError objects.
+type TxnErrors []*TxnError
+
+// TxnResponse is the internal format we receive from Consul.
+type TxnResponse struct {
+	Results TxnResults
+	Errors  TxnErrors
+}
+
 // Txn is used to apply multiple KV operations in a single, atomic transaction.
 // Note that Go will perform the required base64 encoding on the values
 // automatically because the type is a byte slice. Transactions are defined as a
 // list of operations to perform, using the KVOp constants and KVTxnOp structure
 // to define operations. If any operation fails, none of the changes are applied
-// to the state store.
+// to the state store. Note that this hides the internal raw transaction interface
+// and munges the input and output types into KV-specific ones for ease of use.
+// If there are more non-KV operations in the future we may break out a new
+// transaction API client, but it will be easy to keep this KV-specific variant
+// supported.
 //
 // Here's an example:
 //
-// txn := KVTxn{
+// ops := KVTxnOps{
-//     KVTxnOp{
+//     &KVTxnOp{
-//         Op:    KVLock,
+//         Verb:    KVLock,
-//         Key:   "test/lock",
+//         Key:     "test/lock",
 //         Session: "adf4238a-882b-9ddc-4a9d-5b6758e4159e",
-//         Value: []byte("hello"),
+//         Value:   []byte("hello"),
 //     },
-//     KVTxnOp{
+//     &KVTxnOp{
-//         Op:    KVGet,
+//         Verb:    KVGet,
-//         Key:   "another/key",
+//         Key:     "another/key",
 //     },
 // }
-// ok, result, _, err := kv.Txn(&txn, nil)
+// ok, response, _, err := kv.Txn(&ops, nil)
 //
 // If there is a problem making the transaction request then an error will be
 // returned. Otherwise, the ok value will be true if the transaction succeeded
-// or false if it was rolled back. The result is a structured return value which
+// or false if it was rolled back. The response is a structured return value which
 // will have the outcome of the transaction. Its Results member will have entries
 // for each operation. Deleted keys will have a nil entry in the, and to save
 // space, the Value of each key in the Results will be nil unless the operation
 // is a KVGet. If the transaction was rolled back, the Errors member will have
 // entries referencing the index of the operation that failed along with an error
 // message.
-func (k *KV) Txn(txn *KVTxn, q *WriteOptions) (bool, *KVTxnResult, *WriteMeta, error) {
+func (k *KV) Txn(txn KVTxnOps, q *WriteOptions) (bool, *KVTxnResponse, *WriteMeta, error) {
 	r := k.c.newRequest("PUT", "/v1/txn")
 	r.setWriteOptions(q)
 
-	r.obj = txn
+	// Convert into the internal format since this is an all-KV txn.
+	ops := make(TxnOps, 0, len(txn))
+	for _, kvsOp := range txn {
+		ops = append(ops, &TxnOp{KVS: kvsOp})
+	}
+	r.obj = ops
 	rtt, resp, err := k.c.doRequest(r)
 	if err != nil {
 		return false, nil, nil, err
@@ -331,11 +363,23 @@ func (k *KV) Txn(txn *KVTxn, q *WriteOptions) (bool, *KVTxnResult, *WriteMeta, e
 	wm.RequestTime = rtt
 
 	if resp.StatusCode == http.StatusOK || resp.StatusCode == http.StatusConflict {
-		var result KVTxnResult
+		var txnResp TxnResponse
-		if err := decodeBody(resp, &result); err != nil {
+		if err := decodeBody(resp, &txnResp); err != nil {
 			return false, nil, nil, err
 		}
-		return resp.StatusCode == http.StatusOK, &result, wm, nil
+
+		// Convert from the internal format.
+		kvResp := KVTxnResponse{
+			Errors: txnResp.Errors,
+		}
+		for _, result := range txnResp.Results {
+			var entry *KVPair
+			if result.KVS != nil {
+				entry = result.KVS.DirEnt
+			}
+			kvResp.Results = append(kvResp.Results, entry)
+		}
+		return resp.StatusCode == http.StatusOK, &kvResp, wm, nil
 	}
 
 	var buf bytes.Buffer

api/kv_test.go

@@ -466,18 +466,18 @@ func TestClient_Txn(t *testing.T) {
 	// session.
 	key := testKey()
 	value := []byte("test")
-	txn := KVTxn{
+	txn := KVTxnOps{
-		KVTxnOp{
+		&KVTxnOp{
-			Op:    KVLock,
+			Verb:  KVLock,
 			Key:   key,
 			Value: value,
 		},
-		KVTxnOp{
+		&KVTxnOp{
-			Op:  KVGet,
+			Verb: KVGet,
-			Key: key,
+			Key:  key,
 		},
 	}
-	ok, ret, _, err := kv.Txn(&txn, nil)
+	ok, ret, _, err := kv.Txn(txn, nil)
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	} else if ok {
@@ -494,7 +494,7 @@ func TestClient_Txn(t *testing.T) {
 
 	// Now poke in a real session and try again.
 	txn[0].Session = id
-	ok, ret, _, err = kv.Txn(&txn, nil)
+	ok, ret, _, err = kv.Txn(txn, nil)
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	} else if !ok {

command/agent/txn_endpoint.go

@@ -10,14 +10,14 @@ import (
 	"github.com/hashicorp/consul/consul/structs"
 )
 
-// fixupValues takes the raw decoded JSON and base64 decodes all the values,
+// fixupKVSOps takes the raw decoded JSON and base64 decodes all the KVS values,
 // replacing them with byte arrays with the data.
-func fixupValues(raw interface{}) error {
+func fixupKVSOps(raw interface{}) error {
 	// decodeValue decodes the value member of the given operation.
-	decodeValue := func(rawOp interface{}) error {
+	decodeValue := func(rawKVS interface{}) error {
-		rawMap, ok := rawOp.(map[string]interface{})
+		rawMap, ok := rawKVS.(map[string]interface{})
 		if !ok {
-			return fmt.Errorf("unexpected raw op type: %T", rawOp)
+			return fmt.Errorf("unexpected raw KVS type: %T", rawKVS)
 		}
 		for k, v := range rawMap {
 			switch strings.ToLower(k) {
@@ -41,7 +41,25 @@ func fixupValues(raw interface{}) error {
 				return nil
 			}
 		}
+		return nil
+	}
 
+	// fixupKVSOp looks for non-nil KVS operations and passes them on for
+	// value conversion.
+	fixupKVSOp := func(rawOp interface{}) error {
+		rawMap, ok := rawOp.(map[string]interface{})
+		if !ok {
+			return fmt.Errorf("unexpected raw op type: %T", rawOp)
+		}
+		for k, v := range rawMap {
+			switch strings.ToLower(k) {
+			case "kvs":
+				if v == nil {
+					return nil
+				}
+				return decodeValue(v)
+			}
+		}
 		return nil
 	}
 
@@ -50,11 +68,10 @@ func fixupValues(raw interface{}) error {
 		return fmt.Errorf("unexpected raw type: %t", raw)
 	}
 	for _, rawOp := range rawSlice {
-		if err := decodeValue(rawOp); err != nil {
+		if err := fixupKVSOp(rawOp); err != nil {
 			return err
 		}
 	}
-
 	return nil
 }
 
@@ -66,44 +83,53 @@ func (s *HTTPServer) Txn(resp http.ResponseWriter, req *http.Request) (interface
 		return nil, nil
 	}
 
-	var args structs.KVSAtomicRequest
+	var args structs.TxnRequest
 	s.parseDC(req, &args.Datacenter)
 	s.parseToken(req, &args.Token)
 
 	// Note the body is in API format, and not the RPC format. If we can't
 	// decode it, we will return a 400 since we don't have enough context to
 	// associate the error with a given operation.
-	var txn api.KVTxn
+	var ops api.TxnOps
-	if err := decodeBody(req, &txn, fixupValues); err != nil {
+	if err := decodeBody(req, &ops, fixupKVSOps); err != nil {
 		resp.WriteHeader(http.StatusBadRequest)
 		resp.Write([]byte(fmt.Sprintf("Failed to parse body: %v", err)))
 		return nil, nil
 	}
 
-	// Convert the API format into the RPC format. Note that fixupValues
+	// Convert the KVS API format into the RPC format. Note that fixupKVSOps
 	// above will have already converted the base64 encoded strings into
 	// byte arrays so we can assign right over.
-	for _, in := range txn {
+	for _, in := range ops {
-		// TODO @slackpad - Verify the size here, or move that down into
+		if in.KVS != nil {
-		// the endpoint.
+			if size := len(in.KVS.Value); size > maxKVSize {
-		out := &structs.KVSAtomicOp{
+				resp.WriteHeader(http.StatusRequestEntityTooLarge)
-			Op: structs.KVSOp(in.Op),
+				resp.Write([]byte(fmt.Sprintf("Value for key %q is too large (%d > %d bytes)",
-			DirEnt: structs.DirEntry{
+					in.KVS.Key, size, maxKVSize)))
-				Key:     in.Key,
+				return nil, nil
-				Value:   in.Value,
+			}
-				Flags:   in.Flags,
+
-				Session: in.Session,
+			out := &structs.TxnOp{
-				RaftIndex: structs.RaftIndex{
+				KVS: &structs.TxnKVSOp{
-					ModifyIndex: in.Index,
+					Verb: structs.KVSOp(in.KVS.Verb),
+					DirEnt: structs.DirEntry{
+						Key:     in.KVS.Key,
+						Value:   in.KVS.Value,
+						Flags:   in.KVS.Flags,
+						Session: in.KVS.Session,
+						RaftIndex: structs.RaftIndex{
+							ModifyIndex: in.KVS.Index,
+						},
+					},
 				},
-			},
+			}
+			args.Ops = append(args.Ops, out)
 		}
-		args.Ops = append(args.Ops, out)
 	}
 
 	// Make the request and return a conflict status if there were errors
 	// reported from the transaction.
-	var reply structs.KVSAtomicResponse
+	var reply structs.TxnResponse
 	if err := s.agent.RPC("Txn.Apply", &args, &reply); err != nil {
 		return nil, err
 	}

command/agent/txn_endpoint_test.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"reflect"
+	"strings"
 	"testing"
 
 	"github.com/hashicorp/consul/consul/structs"
@@ -50,6 +51,34 @@ func TestTxnEndpoint_Bad_Method(t *testing.T) {
 	})
 }
 
+func TestTxnEndpoint_Bad_Size(t *testing.T) {
+	httpTest(t, func(srv *HTTPServer) {
+		buf := bytes.NewBuffer([]byte(fmt.Sprintf(`
+[
+    {
+        "KVS": {
+            "Verb": "set",
+            "Key": "key",
+            "Value": %q
+        }
+    }
+]
+`, strings.Repeat("bad", 2*maxKVSize))))
+		req, err := http.NewRequest("PUT", "/v1/txn", buf)
+		if err != nil {
+			t.Fatalf("err: %v", err)
+		}
+
+		resp := httptest.NewRecorder()
+		if _, err := srv.Txn(resp, req); err != nil {
+			t.Fatalf("err: %v", err)
+		}
+		if resp.Code != 413 {
+			t.Fatalf("expected 413, got %d", resp.Code)
+		}
+	})
+}
+
 func TestTxnEndpoint_KVS_Actions(t *testing.T) {
 	httpTest(t, func(srv *HTTPServer) {
 		// Make sure all incoming fields get converted properly to the internal
@@ -60,15 +89,19 @@ func TestTxnEndpoint_KVS_Actions(t *testing.T) {
 			buf := bytes.NewBuffer([]byte(fmt.Sprintf(`
 [
     {
-        "Op": "lock",
+        "KVS": {
-        "Key": "key",
+            "Verb": "lock",
-        "Value": "aGVsbG8gd29ybGQ=",
+            "Key": "key",
-        "Flags": 23,
+            "Value": "aGVsbG8gd29ybGQ=",
-        "Session": %q
+            "Flags": 23,
+            "Session": %q
+        }
     },
     {
-        "Op": "get",
+        "KVS": {
-        "Key": "key"
+            "Verb": "get",
+            "Key": "key"
+        }
     }
 ]
 `, id)))
@@ -86,42 +119,50 @@ func TestTxnEndpoint_KVS_Actions(t *testing.T) {
 				t.Fatalf("expected 200, got %d", resp.Code)
 			}
 
-			atomic, ok := obj.(structs.KVSAtomicResponse)
+			txnResp, ok := obj.(structs.TxnResponse)
 			if !ok {
 				t.Fatalf("bad type: %T", obj)
 			}
-			if len(atomic.Results) != 2 {
+			if len(txnResp.Results) != 2 {
-				t.Fatalf("bad: %v", atomic)
+				t.Fatalf("bad: %v", txnResp)
 			}
-			index = atomic.Results[0].ModifyIndex
+			index = txnResp.Results[0].KVS.DirEnt.ModifyIndex
-			expected := structs.KVSAtomicResponse{
+			expected := structs.TxnResponse{
-				Results: structs.DirEntries{
+				Results: structs.TxnResults{
-					&structs.DirEntry{
+					&structs.TxnResult{
-						Key:       "key",
+						KVS: &structs.TxnKVSResult{
-						Value:     nil,
+							DirEnt: &structs.DirEntry{
-						Flags:     23,
+								Key:       "key",
-						Session:   id,
+								Value:     nil,
-						LockIndex: 1,
+								Flags:     23,
-						RaftIndex: structs.RaftIndex{
+								Session:   id,
-							CreateIndex: index,
+								LockIndex: 1,
-							ModifyIndex: index,
+								RaftIndex: structs.RaftIndex{
+									CreateIndex: index,
+									ModifyIndex: index,
+								},
+							},
 						},
 					},
-					&structs.DirEntry{
+					&structs.TxnResult{
-						Key:       "key",
+						KVS: &structs.TxnKVSResult{
-						Value:     []byte("hello world"),
+							DirEnt: &structs.DirEntry{
-						Flags:     23,
+								Key:       "key",
-						Session:   id,
+								Value:     []byte("hello world"),
-						LockIndex: 1,
+								Flags:     23,
-						RaftIndex: structs.RaftIndex{
+								Session:   id,
-							CreateIndex: index,
+								LockIndex: 1,
-							ModifyIndex: index,
+								RaftIndex: structs.RaftIndex{
+									CreateIndex: index,
+									ModifyIndex: index,
+								},
+							},
 						},
 					},
 				},
 			}
-			if !reflect.DeepEqual(atomic, expected) {
+			if !reflect.DeepEqual(txnResp, expected) {
-				t.Fatalf("bad: %v", atomic)
+				t.Fatalf("bad: %v", txnResp)
 			}
 		}
 
@@ -131,14 +172,18 @@ func TestTxnEndpoint_KVS_Actions(t *testing.T) {
 			buf := bytes.NewBuffer([]byte(fmt.Sprintf(`
 [
     {
-        "Op": "cas",
+        "KVS": {
-        "Key": "key",
+            "Verb": "cas",
-        "Value": "Z29vZGJ5ZSB3b3JsZA==",
+            "Key": "key",
-        "Index": %d
+            "Value": "Z29vZGJ5ZSB3b3JsZA==",
+            "Index": %d
+        }
     },
     {
-        "Op": "get",
+        "KVS": {
-        "Key": "key"
+            "Verb": "get",
+            "Key": "key"
+        }
     }
 ]
 `, index)))
@@ -156,38 +201,46 @@ func TestTxnEndpoint_KVS_Actions(t *testing.T) {
 				t.Fatalf("expected 200, got %d", resp.Code)
 			}
 
-			atomic, ok := obj.(structs.KVSAtomicResponse)
+			txnResp, ok := obj.(structs.TxnResponse)
 			if !ok {
 				t.Fatalf("bad type: %T", obj)
 			}
-			if len(atomic.Results) != 2 {
+			if len(txnResp.Results) != 2 {
-				t.Fatalf("bad: %v", atomic)
+				t.Fatalf("bad: %v", txnResp)
 			}
-			modIndex := atomic.Results[0].ModifyIndex
+			modIndex := txnResp.Results[0].KVS.DirEnt.ModifyIndex
-			expected := structs.KVSAtomicResponse{
+			expected := structs.TxnResponse{
-				Results: structs.DirEntries{
+				Results: structs.TxnResults{
-					&structs.DirEntry{
+					&structs.TxnResult{
-						Key:     "key",
+						KVS: &structs.TxnKVSResult{
-						Value:   nil,
+							DirEnt: &structs.DirEntry{
-						Session: id,
+								Key:     "key",
-						RaftIndex: structs.RaftIndex{
+								Value:   nil,
-							CreateIndex: index,
+								Session: id,
-							ModifyIndex: modIndex,
+								RaftIndex: structs.RaftIndex{
+									CreateIndex: index,
+									ModifyIndex: modIndex,
+								},
+							},
 						},
 					},
-					&structs.DirEntry{
+					&structs.TxnResult{
-						Key:     "key",
+						KVS: &structs.TxnKVSResult{
-						Value:   []byte("goodbye world"),
+							DirEnt: &structs.DirEntry{
-						Session: id,
+								Key:     "key",
-						RaftIndex: structs.RaftIndex{
+								Value:   []byte("goodbye world"),
-							CreateIndex: index,
+								Session: id,
-							ModifyIndex: modIndex,
+								RaftIndex: structs.RaftIndex{
+									CreateIndex: index,
+									ModifyIndex: modIndex,
+								},
+							},
 						},
 					},
 				},
 			}
-			if !reflect.DeepEqual(atomic, expected) {
+			if !reflect.DeepEqual(txnResp, expected) {
-				t.Fatalf("bad: %v", atomic)
+				t.Fatalf("bad: %v", txnResp)
 			}
 		}
 	})
@@ -197,14 +250,18 @@ func TestTxnEndpoint_KVS_Actions(t *testing.T) {
 		buf := bytes.NewBuffer([]byte(`
 [
     {
-        "Op": "lock",
+        "KVS": {
-        "Key": "key",
+            "Verb": "lock",
-        "Value": "aGVsbG8gd29ybGQ=",
+            "Key": "key",
-        "Session": "nope"
+            "Value": "aGVsbG8gd29ybGQ=",
+            "Session": "nope"
+        }
     },
     {
-        "Op": "get",
+        "KVS": {
-        "Key": "key"
+            "Verb": "get",
+            "Key": "key"
+        }
     }
 ]
 `))

consul/fsm.go

@@ -83,8 +83,6 @@ func (c *consulFSM) Apply(log *raft.Log) interface{} {
 		return c.applyDeregister(buf[1:], log.Index)
 	case structs.KVSRequestType:
 		return c.applyKVSOperation(buf[1:], log.Index)
-	case structs.KVSAtomicRequestType:
-		return c.applyKVSAtomicOperation(buf[1:], log.Index)
 	case structs.SessionRequestType:
 		return c.applySessionOperation(buf[1:], log.Index)
 	case structs.ACLRequestType:
@@ -95,6 +93,8 @@ func (c *consulFSM) Apply(log *raft.Log) interface{} {
 		return c.applyCoordinateBatchUpdate(buf[1:], log.Index)
 	case structs.PreparedQueryRequestType:
 		return c.applyPreparedQueryOperation(buf[1:], log.Index)
+	case structs.TxnRequestType:
+		return c.applyTxn(buf[1:], log.Index)
 	default:
 		if ignoreUnknown {
 			c.logger.Printf("[WARN] consul.fsm: ignoring unknown message type (%d), upgrade to newer version", msgType)
@@ -195,16 +195,6 @@ func (c *consulFSM) applyKVSOperation(buf []byte, index uint64) interface{} {
 	}
 }
 
-func (c *consulFSM) applyKVSAtomicOperation(buf []byte, index uint64) interface{} {
-	var req structs.KVSAtomicRequest
-	if err := structs.Decode(buf, &req); err != nil {
-		panic(fmt.Errorf("failed to decode request: %v", err))
-	}
-	defer metrics.MeasureSince([]string{"consul", "fsm", "kvs-atomic"}, time.Now())
-	entries, errors := c.state.KVSAtomicUpdate(index, req.Ops)
-	return structs.KVSAtomicResponse{errors, entries}
-}
-
 func (c *consulFSM) applySessionOperation(buf []byte, index uint64) interface{} {
 	var req structs.SessionRequest
 	if err := structs.Decode(buf, &req); err != nil {
@@ -298,6 +288,16 @@ func (c *consulFSM) applyPreparedQueryOperation(buf []byte, index uint64) interf
 	}
 }
 
+func (c *consulFSM) applyTxn(buf []byte, index uint64) interface{} {
+	var req structs.TxnRequest
+	if err := structs.Decode(buf, &req); err != nil {
+		panic(fmt.Errorf("failed to decode request: %v", err))
+	}
+	defer metrics.MeasureSince([]string{"consul", "fsm", "txn"}, time.Now())
+	results, errors := c.state.TxnRun(index, req.Ops)
+	return structs.TxnResponse{results, errors}
+}
+
 func (c *consulFSM) Snapshot() (raft.FSMSnapshot, error) {
 	defer func(start time.Time) {
 		c.logger.Printf("[INFO] consul.fsm: snapshot created in %v", time.Now().Sub(start))

consul/fsm_test.go

@@ -1241,6 +1241,47 @@ func TestFSM_TombstoneReap(t *testing.T) {
 	}
 }
 
+func TestFSM_Txn(t *testing.T) {
+	fsm, err := NewFSM(nil, os.Stderr)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// Set a key using a transaction.
+	req := structs.TxnRequest{
+		Datacenter: "dc1",
+		Ops: structs.TxnOps{
+			&structs.TxnOp{
+				KVS: &structs.TxnKVSOp{
+					Verb: structs.KVSSet,
+					DirEnt: structs.DirEntry{
+						Key:   "/test/path",
+						Flags: 0,
+						Value: []byte("test"),
+					},
+				},
+			},
+		},
+	}
+	buf, err := structs.Encode(structs.TxnRequestType, req)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	resp := fsm.Apply(makeLog(buf))
+	if _, ok := resp.(structs.TxnResponse); !ok {
+		t.Fatalf("bad response type: %T", resp)
+	}
+
+	// Verify key is set directly in the state store.
+	_, d, err := fsm.state.KVSGet("/test/path")
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if d == nil {
+		t.Fatalf("missing")
+	}
+}
+
 func TestFSM_IgnoreUnknown(t *testing.T) {
 	fsm, err := NewFSM(nil, os.Stderr)
 	if err != nil {

consul/kvs_endpoint.go

@@ -31,9 +31,9 @@ func kvsPreApply(srv *Server, acl acl.ACL, op structs.KVSOp, dirEnt *structs.Dir
 				return false, permissionDeniedErr
 			}
 
-		case structs.KVSAtomicGet,
+		case structs.KVSGet,
-			structs.KVSAtomicCheckSession,
+			structs.KVSCheckSession,
-			structs.KVSAtomicCheckIndex:
+			structs.KVSCheckIndex:
 			if !acl.KeyRead(dirEnt.Key) {
 				return false, permissionDeniedErr
 			}

consul/state/kvs.go

@@ -579,103 +579,6 @@ func (s *StateStore) kvsUnlockTxn(tx *memdb.Txn, idx uint64, entry *structs.DirE
 	return true, nil
 }
 
-// KVSAtomicUpdate performs a series of updates atomically, all inside a single
-// transaction that only succeeds if all the operations succeed.
-func (s *StateStore) KVSAtomicUpdate(idx uint64, ops structs.KVSAtomicOps) (structs.DirEntries, structs.KVSAtomicErrors) {
-	tx := s.db.Txn(true)
-	defer tx.Abort()
-
-	// Dispatch all of the operations inside the transaction.
-	entries := make(structs.DirEntries, 0, len(ops))
-	errors := make(structs.KVSAtomicErrors, 0, len(ops))
-	for i, op := range ops {
-		var entry *structs.DirEntry
-		var err error
-
-		switch op.Op {
-		case structs.KVSSet:
-			entry = &op.DirEnt
-			err = s.kvsSetTxn(tx, idx, entry, false)
-
-		case structs.KVSDelete:
-			err = s.kvsDeleteTxn(tx, idx, op.DirEnt.Key)
-
-		case structs.KVSDeleteCAS:
-			var ok bool
-			ok, err = s.kvsDeleteCASTxn(tx, idx, op.DirEnt.ModifyIndex, op.DirEnt.Key)
-			if !ok && err == nil {
-				err = fmt.Errorf("failed to delete key %q, index is stale", op.DirEnt.Key)
-			}
-
-		case structs.KVSDeleteTree:
-			err = s.kvsDeleteTreeTxn(tx, idx, op.DirEnt.Key)
-
-		case structs.KVSCAS:
-			var ok bool
-			entry = &op.DirEnt
-			ok, err = s.kvsSetCASTxn(tx, idx, entry)
-			if !ok && err == nil {
-				err = fmt.Errorf("failed to set key %q, index is stale", op.DirEnt.Key)
-			}
-
-		case structs.KVSLock:
-			var ok bool
-			entry = &op.DirEnt
-			ok, err = s.kvsLockTxn(tx, idx, entry)
-			if !ok && err == nil {
-				err = fmt.Errorf("failed to lock key %q, lock is already held", op.DirEnt.Key)
-			}
-
-		case structs.KVSUnlock:
-			var ok bool
-			entry = &op.DirEnt
-			ok, err = s.kvsUnlockTxn(tx, idx, entry)
-			if !ok && err == nil {
-				err = fmt.Errorf("failed to unlock key %q, lock isn't held, or is held by another session", op.DirEnt.Key)
-			}
-
-		case structs.KVSAtomicGet:
-			_, entry, err = s.kvsGetTxn(tx, op.DirEnt.Key)
-
-		case structs.KVSAtomicCheckSession:
-			entry, err = s.kvsCheckSessionTxn(tx, op.DirEnt.Key, op.DirEnt.Session)
-
-		case structs.KVSAtomicCheckIndex:
-			entry, err = s.kvsCheckIndexTxn(tx, op.DirEnt.Key, op.DirEnt.ModifyIndex)
-
-		default:
-			err = fmt.Errorf("unknown operation %q", op.Op)
-		}
-
-		// Accumulate the entries. 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.Op == structs.KVSAtomicGet {
-				entries = append(entries, entry)
-			} else {
-				clone := entry.Clone()
-				clone.Value = nil
-				entries = append(entries, clone)
-			}
-		} else {
-			entries = append(entries, nil)
-		}
-
-		// Capture any error along with the index of the operation that
-		// failed.
-		if err != nil {
-			errors = append(errors, &structs.KVSAtomicError{i, err.Error()})
-		}
-	}
-	if len(errors) > 0 {
-		return nil, errors
-	}
-
-	tx.Commit()
-	return entries, nil
-}
-
 // kvsCheckSessionTxn checks to see if the given session matches the current
 // entry for a key.
 func (s *StateStore) kvsCheckSessionTxn(tx *memdb.Txn, key string, session string) (*structs.DirEntry, error) {

consul/state/kvs_test.go

@@ -1214,453 +1214,6 @@ func TestStateStore_KVSUnlock(t *testing.T) {
 	}
 }
 
-func TestStateStore_KVS_Atomic(t *testing.T) {
-	s := testStateStore(t)
-
-	// Create kvs entries in the state store.
-	testSetKey(t, s, 1, "foo/delete", "bar")
-	testSetKey(t, s, 2, "foo/bar/baz", "baz")
-	testSetKey(t, s, 3, "foo/bar/zip", "zip")
-	testSetKey(t, s, 4, "foo/zorp", "zorp")
-	testSetKey(t, s, 5, "foo/update", "stale")
-
-	// Make a real session.
-	testRegisterNode(t, s, 6, "node1")
-	session := testUUID()
-	if err := s.SessionCreate(7, &structs.Session{ID: session, Node: "node1"}); err != nil {
-		t.Fatalf("err: %s", err)
-	}
-
-	// Set up a transaction that hits every operation.
-	ops := structs.KVSAtomicOps{
-		&structs.KVSAtomicOp{
-			Op: structs.KVSSet,
-			DirEnt: structs.DirEntry{
-				Key:   "foo/new",
-				Value: []byte("one"),
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSDelete,
-			DirEnt: structs.DirEntry{
-				Key: "foo/zorp",
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSDeleteCAS,
-			DirEnt: structs.DirEntry{
-				Key: "foo/delete",
-				RaftIndex: structs.RaftIndex{
-					ModifyIndex: 1,
-				},
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSDeleteTree,
-			DirEnt: structs.DirEntry{
-				Key: "foo/bar",
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSAtomicGet,
-			DirEnt: structs.DirEntry{
-				Key: "foo/update",
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSAtomicCheckIndex,
-			DirEnt: structs.DirEntry{
-				Key: "foo/update",
-				RaftIndex: structs.RaftIndex{
-					ModifyIndex: 5,
-				},
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSCAS,
-			DirEnt: structs.DirEntry{
-				Key:   "foo/update",
-				Value: []byte("new"),
-				RaftIndex: structs.RaftIndex{
-					ModifyIndex: 5,
-				},
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSAtomicGet,
-			DirEnt: structs.DirEntry{
-				Key: "foo/update",
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSAtomicGet,
-			DirEnt: structs.DirEntry{
-				Key: "not/there",
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSAtomicCheckIndex,
-			DirEnt: structs.DirEntry{
-				Key: "foo/update",
-				RaftIndex: structs.RaftIndex{
-					ModifyIndex: 8,
-				},
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSAtomicGet,
-			DirEnt: structs.DirEntry{
-				Key: "foo/lock",
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSLock,
-			DirEnt: structs.DirEntry{
-				Key:     "foo/lock",
-				Session: session,
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSAtomicCheckSession,
-			DirEnt: structs.DirEntry{
-				Key:     "foo/lock",
-				Session: session,
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSUnlock,
-			DirEnt: structs.DirEntry{
-				Key:     "foo/lock",
-				Session: session,
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSAtomicCheckSession,
-			DirEnt: structs.DirEntry{
-				Key:     "foo/lock",
-				Session: "",
-			},
-		},
-	}
-	entries, errors := s.KVSAtomicUpdate(8, ops)
-	if len(errors) > 0 {
-		t.Fatalf("err: %v", errors)
-	}
-	if len(entries) != len(ops) {
-		t.Fatalf("bad len: %d != %d", len(entries), len(ops))
-	}
-
-	// Make sure the response looks as expected.
-	expected := structs.DirEntries{
-		&structs.DirEntry{
-			Key: "foo/new",
-			RaftIndex: structs.RaftIndex{
-				CreateIndex: 8,
-				ModifyIndex: 8,
-			},
-		},
-		nil, // delete
-		nil, // delete tree
-		nil, // delete CAS
-		&structs.DirEntry{
-			Key:   "foo/update",
-			Value: []byte("stale"),
-			RaftIndex: structs.RaftIndex{
-				CreateIndex: 5,
-				ModifyIndex: 5,
-			},
-		},
-		&structs.DirEntry{
-			Key: "foo/update",
-			RaftIndex: structs.RaftIndex{
-				CreateIndex: 5,
-				ModifyIndex: 5,
-			},
-		},
-		&structs.DirEntry{
-			Key: "foo/update",
-			RaftIndex: structs.RaftIndex{
-				CreateIndex: 5,
-				ModifyIndex: 8,
-			},
-		},
-		&structs.DirEntry{
-			Key:   "foo/update",
-			Value: []byte("new"),
-			RaftIndex: structs.RaftIndex{
-				CreateIndex: 5,
-				ModifyIndex: 8,
-			},
-		},
-		nil, // get on not/there
-		&structs.DirEntry{
-			Key: "foo/update",
-			RaftIndex: structs.RaftIndex{
-				CreateIndex: 5,
-				ModifyIndex: 8,
-			},
-		},
-		nil, // get on foo/lock before it's created
-		&structs.DirEntry{
-			Key:       "foo/lock",
-			Session:   session,
-			LockIndex: 1,
-			RaftIndex: structs.RaftIndex{
-				CreateIndex: 8,
-				ModifyIndex: 8,
-			},
-		},
-		&structs.DirEntry{
-			Key:       "foo/lock",
-			Session:   session,
-			LockIndex: 1,
-			RaftIndex: structs.RaftIndex{
-				CreateIndex: 8,
-				ModifyIndex: 8,
-			},
-		},
-		&structs.DirEntry{
-			Key:       "foo/lock",
-			LockIndex: 1,
-			RaftIndex: structs.RaftIndex{
-				CreateIndex: 8,
-				ModifyIndex: 8,
-			},
-		},
-		&structs.DirEntry{
-			Key:       "foo/lock",
-			LockIndex: 1,
-			RaftIndex: structs.RaftIndex{
-				CreateIndex: 8,
-				ModifyIndex: 8,
-			},
-		},
-	}
-	if len(entries) != len(expected) {
-		t.Fatalf("bad: %v", entries)
-	}
-	for i, _ := range entries {
-		if !reflect.DeepEqual(entries[i], expected[i]) {
-			t.Fatalf("bad %d: %v != %v", i, *(entries[i]), *(expected[i]))
-		}
-	}
-
-	// Pull the resulting state store contents.
-	idx, actual, err := s.KVSList("")
-	if err != nil {
-		t.Fatalf("err: %s", err)
-	}
-	if idx != 8 {
-		t.Fatalf("bad index: %d", idx)
-	}
-
-	// Make sure it looks as expected.
-	expected = structs.DirEntries{
-		&structs.DirEntry{
-			Key:       "foo/lock",
-			LockIndex: 1,
-			RaftIndex: structs.RaftIndex{
-				CreateIndex: 8,
-				ModifyIndex: 8,
-			},
-		},
-		&structs.DirEntry{
-			Key:   "foo/new",
-			Value: []byte("one"),
-			RaftIndex: structs.RaftIndex{
-				CreateIndex: 8,
-				ModifyIndex: 8,
-			},
-		},
-		&structs.DirEntry{
-			Key:   "foo/update",
-			Value: []byte("new"),
-			RaftIndex: structs.RaftIndex{
-				CreateIndex: 5,
-				ModifyIndex: 8,
-			},
-		},
-	}
-	if len(actual) != len(expected) {
-		t.Fatalf("bad len: %d != %d", len(actual), len(expected))
-	}
-	for i, _ := range actual {
-		if !reflect.DeepEqual(actual[i], expected[i]) {
-			t.Fatalf("bad %d: %v != %v", i, *(actual[i]), *(expected[i]))
-		}
-	}
-}
-
-func TestStateStore_KVS_Atomic_Rollback(t *testing.T) {
-	s := testStateStore(t)
-
-	// Create kvs entries in the state store.
-	testSetKey(t, s, 1, "foo/delete", "bar")
-	testSetKey(t, s, 2, "foo/update", "stale")
-
-	testRegisterNode(t, s, 3, "node1")
-	session := testUUID()
-	if err := s.SessionCreate(4, &structs.Session{ID: session, Node: "node1"}); err != nil {
-		t.Fatalf("err: %s", err)
-	}
-	ok, err := s.KVSLock(5, &structs.DirEntry{Key: "foo/lock", Value: []byte("foo"), Session: session})
-	if !ok || err != nil {
-		t.Fatalf("didn't get the lock: %v %s", ok, err)
-	}
-
-	bogus := testUUID()
-	if err := s.SessionCreate(6, &structs.Session{ID: bogus, Node: "node1"}); err != nil {
-		t.Fatalf("err: %s", err)
-	}
-
-	// This function verifies that the state store wasn't changed.
-	verifyStateStore := func(desc string) {
-		idx, actual, err := s.KVSList("")
-		if err != nil {
-			t.Fatalf("err (%s): %s", desc, err)
-		}
-		if idx != 5 {
-			t.Fatalf("bad index (%s): %d", desc, idx)
-		}
-
-		// Make sure it looks as expected.
-		expected := structs.DirEntries{
-			&structs.DirEntry{
-				Key:   "foo/delete",
-				Value: []byte("bar"),
-				RaftIndex: structs.RaftIndex{
-					CreateIndex: 1,
-					ModifyIndex: 1,
-				},
-			},
-			&structs.DirEntry{
-				Key:       "foo/lock",
-				Value:     []byte("foo"),
-				LockIndex: 1,
-				Session:   session,
-				RaftIndex: structs.RaftIndex{
-					CreateIndex: 5,
-					ModifyIndex: 5,
-				},
-			},
-			&structs.DirEntry{
-				Key:   "foo/update",
-				Value: []byte("stale"),
-				RaftIndex: structs.RaftIndex{
-					CreateIndex: 2,
-					ModifyIndex: 2,
-				},
-			},
-		}
-		if len(actual) != len(expected) {
-			t.Fatalf("bad len (%s): %d != %d", desc, len(actual), len(expected))
-		}
-		for i, _ := range actual {
-			if !reflect.DeepEqual(actual[i], expected[i]) {
-				t.Fatalf("bad (%s): op %d: %v != %v", desc, i, *(actual[i]), *(expected[i]))
-			}
-		}
-	}
-	verifyStateStore("initial")
-
-	// Set up a transaction that fails every operation.
-	ops := structs.KVSAtomicOps{
-		&structs.KVSAtomicOp{
-			Op: structs.KVSCAS,
-			DirEnt: structs.DirEntry{
-				Key:   "foo/update",
-				Value: []byte("new"),
-				RaftIndex: structs.RaftIndex{
-					ModifyIndex: 1,
-				},
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSLock,
-			DirEnt: structs.DirEntry{
-				Key:     "foo/lock",
-				Session: bogus,
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSUnlock,
-			DirEnt: structs.DirEntry{
-				Key:     "foo/lock",
-				Session: bogus,
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSAtomicCheckSession,
-			DirEnt: structs.DirEntry{
-				Key:     "foo/lock",
-				Session: bogus,
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSAtomicCheckSession,
-			DirEnt: structs.DirEntry{
-				Key:     "nope",
-				Session: bogus,
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSAtomicCheckIndex,
-			DirEnt: structs.DirEntry{
-				Key: "foo/lock",
-				RaftIndex: structs.RaftIndex{
-					ModifyIndex: 6,
-				},
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: structs.KVSAtomicCheckIndex,
-			DirEnt: structs.DirEntry{
-				Key: "nope",
-				RaftIndex: structs.RaftIndex{
-					ModifyIndex: 6,
-				},
-			},
-		},
-		&structs.KVSAtomicOp{
-			Op: "nope",
-			DirEnt: structs.DirEntry{
-				Key: "foo/delete",
-			},
-		},
-	}
-	entries, errors := s.KVSAtomicUpdate(7, ops)
-	if len(errors) != len(ops) {
-		t.Fatalf("bad len: %d != %d", len(errors), len(ops))
-	}
-	if len(entries) != 0 {
-		t.Fatalf("bad len: %d != 0", len(entries))
-	}
-	verifyStateStore("after")
-
-	// Make sure the errors look reasonable.
-	expected := []string{
-		"index is stale",
-		"lock is already held",
-		"lock isn't held, or is held by another session",
-		"current session",
-		`key "nope" doesn't exist`,
-		"current modify index",
-		`key "nope" doesn't exist`,
-		"unknown operation",
-	}
-	if len(errors) != len(expected) {
-		t.Fatalf("bad len: %d != %d", len(errors), len(expected))
-	}
-	for i, msg := range expected {
-		if errors[i].OpIndex != i {
-			t.Fatalf("bad index: %d != %d", i, errors[i].OpIndex)
-		}
-		if !strings.Contains(errors[i].Error(), msg) {
-			t.Fatalf("bad %d: %v", i, errors[i].Error())
-		}
-	}
-}
-
 func TestStateStore_KVS_Snapshot_Restore(t *testing.T) {
 	s := testStateStore(t)
 
@@ -1893,73 +1446,6 @@ func TestStateStore_KVS_Watches(t *testing.T) {
 			})
 		})
 	})
-
-	// Verify that a basic transaction triggers multiple watches. We call
-	// the same underlying methods that are called above so this is more
-	// of a sanity check.
-	verifyWatch(t, s.GetKVSWatch("multi/one"), func() {
-		verifyWatch(t, s.GetKVSWatch("multi/two"), func() {
-			ops := structs.KVSAtomicOps{
-				&structs.KVSAtomicOp{
-					Op: structs.KVSSet,
-					DirEnt: structs.DirEntry{
-						Key:   "multi/one",
-						Value: []byte("one"),
-					},
-				},
-				&structs.KVSAtomicOp{
-					Op: structs.KVSSet,
-					DirEnt: structs.DirEntry{
-						Key:   "multi/two",
-						Value: []byte("two"),
-					},
-				},
-			}
-			entries, errors := s.KVSAtomicUpdate(15, ops)
-			if len(entries) != len(ops) {
-				t.Fatalf("bad len: %d != %d", len(entries), len(ops))
-			}
-			if len(errors) != 0 {
-				t.Fatalf("bad len: %d != 0", len(errors))
-			}
-		})
-	})
-
-	// Verify that a rolled back transaction doesn't trigger any watches.
-	verifyNoWatch(t, s.GetKVSWatch("multi/one"), func() {
-		verifyNoWatch(t, s.GetKVSWatch("multi/two"), func() {
-			ops := structs.KVSAtomicOps{
-				&structs.KVSAtomicOp{
-					Op: structs.KVSSet,
-					DirEnt: structs.DirEntry{
-						Key:   "multi/one",
-						Value: []byte("one-updated"),
-					},
-				},
-				&structs.KVSAtomicOp{
-					Op: structs.KVSSet,
-					DirEnt: structs.DirEntry{
-						Key:   "multi/two",
-						Value: []byte("two-updated"),
-					},
-				},
-				&structs.KVSAtomicOp{
-					Op: structs.KVSLock,
-					DirEnt: structs.DirEntry{
-						Key:   "multi/nope",
-						Value: []byte("nope"),
-					},
-				},
-			}
-			entries, errors := s.KVSAtomicUpdate(16, ops)
-			if len(errors) != 1 {
-				t.Fatalf("bad len: %d != 1", len(errors))
-			}
-			if len(entries) != 0 {
-				t.Fatalf("bad len: %d != 0", len(entries))
-			}
-		})
-	})
 }
 
 func TestStateStore_Tombstone_Snapshot_Restore(t *testing.T) {

consul/state/txn.go

@@ -0,0 +1,123 @@
+package state
+
+import (
+	"fmt"
+
+	"github.com/hashicorp/consul/consul/structs"
+	"github.com/hashicorp/go-memdb"
+)
+
+func (s *StateStore) txnKVS(tx *memdb.Txn, idx uint64, op *structs.TxnKVSOp) (*structs.TxnKVSResult, error) {
+	var entry *structs.DirEntry
+	var err error
+
+	switch op.Verb {
+	case structs.KVSSet:
+		entry = &op.DirEnt
+		err = s.kvsSetTxn(tx, idx, entry, false)
+
+	case structs.KVSDelete:
+		err = s.kvsDeleteTxn(tx, idx, op.DirEnt.Key)
+
+	case structs.KVSDeleteCAS:
+		var ok bool
+		ok, err = s.kvsDeleteCASTxn(tx, idx, op.DirEnt.ModifyIndex, op.DirEnt.Key)
+		if !ok && err == nil {
+			err = fmt.Errorf("failed to delete key %q, index is stale", op.DirEnt.Key)
+		}
+
+	case structs.KVSDeleteTree:
+		err = s.kvsDeleteTreeTxn(tx, idx, op.DirEnt.Key)
+
+	case structs.KVSCAS:
+		var ok bool
+		entry = &op.DirEnt
+		ok, err = s.kvsSetCASTxn(tx, idx, entry)
+		if !ok && err == nil {
+			err = fmt.Errorf("failed to set key %q, index is stale", op.DirEnt.Key)
+		}
+
+	case structs.KVSLock:
+		var ok bool
+		entry = &op.DirEnt
+		ok, err = s.kvsLockTxn(tx, idx, entry)
+		if !ok && err == nil {
+			err = fmt.Errorf("failed to lock key %q, lock is already held", op.DirEnt.Key)
+		}
+
+	case structs.KVSUnlock:
+		var ok bool
+		entry = &op.DirEnt
+		ok, err = s.kvsUnlockTxn(tx, idx, entry)
+		if !ok && err == nil {
+			err = fmt.Errorf("failed to unlock key %q, lock isn't held, or is held by another session", op.DirEnt.Key)
+		}
+
+	case structs.KVSGet:
+		_, entry, err = s.kvsGetTxn(tx, op.DirEnt.Key)
+
+	case structs.KVSCheckSession:
+		entry, err = s.kvsCheckSessionTxn(tx, op.DirEnt.Key, op.DirEnt.Session)
+
+	case structs.KVSCheckIndex:
+		entry, err = s.kvsCheckIndexTxn(tx, op.DirEnt.Key, op.DirEnt.ModifyIndex)
+
+	default:
+		err = fmt.Errorf("unknown KVS 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 == structs.KVSGet {
+			return &structs.TxnKVSResult{entry}, nil
+		}
+
+		clone := entry.Clone()
+		clone.Value = nil
+		return &structs.TxnKVSResult{clone}, nil
+	}
+
+	return nil, nil
+}
+
+// TxnRun tries to run the given operations all inside a single transaction. If
+// any of the operations fail, the entire transaction will be rolled back.
+func (s *StateStore) TxnRun(idx uint64, ops structs.TxnOps) (structs.TxnResults, structs.TxnErrors) {
+	tx := s.db.Txn(true)
+	defer tx.Abort()
+
+	// Dispatch all of the operations inside the transaction.
+	results := make(structs.TxnResults, 0, len(ops))
+	errors := make(structs.TxnErrors, 0, len(ops))
+	for i, op := range ops {
+		var result structs.TxnResult
+		var err error
+
+		// Dispatch based on the type of operation.
+		if op.KVS != nil {
+			result.KVS, err = s.txnKVS(tx, idx, op.KVS)
+		} else {
+			err = fmt.Errorf("no operation specified")
+		}
+
+		// Accumulate the results.
+		results = append(results, &result)
+
+		// Capture any error along with the index of the operation that
+		// failed.
+		if err != nil {
+			errors = append(errors, &structs.TxnError{i, err.Error()})
+		}
+	}
+	if len(errors) > 0 {
+		return nil, errors
+	}
+
+	tx.Commit()
+	return results, nil
+}

consul/state/txn_test.go

@@ -0,0 +1,624 @@
+package state
+
+import (
+	"reflect"
+	"strings"
+	"testing"
+
+	"github.com/hashicorp/consul/consul/structs"
+)
+
+func TestStateStore_Txn_KVS(t *testing.T) {
+	s := testStateStore(t)
+
+	// Create kvs results in the state store.
+	testSetKey(t, s, 1, "foo/delete", "bar")
+	testSetKey(t, s, 2, "foo/bar/baz", "baz")
+	testSetKey(t, s, 3, "foo/bar/zip", "zip")
+	testSetKey(t, s, 4, "foo/zorp", "zorp")
+	testSetKey(t, s, 5, "foo/update", "stale")
+
+	// Make a real session.
+	testRegisterNode(t, s, 6, "node1")
+	session := testUUID()
+	if err := s.SessionCreate(7, &structs.Session{ID: session, Node: "node1"}); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	// Set up a transaction that hits every operation.
+	ops := structs.TxnOps{
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSSet,
+				DirEnt: structs.DirEntry{
+					Key:   "foo/new",
+					Value: []byte("one"),
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSDelete,
+				DirEnt: structs.DirEntry{
+					Key: "foo/zorp",
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSDeleteCAS,
+				DirEnt: structs.DirEntry{
+					Key: "foo/delete",
+					RaftIndex: structs.RaftIndex{
+						ModifyIndex: 1,
+					},
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSDeleteTree,
+				DirEnt: structs.DirEntry{
+					Key: "foo/bar",
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSGet,
+				DirEnt: structs.DirEntry{
+					Key: "foo/update",
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSCheckIndex,
+				DirEnt: structs.DirEntry{
+					Key: "foo/update",
+					RaftIndex: structs.RaftIndex{
+						ModifyIndex: 5,
+					},
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSCAS,
+				DirEnt: structs.DirEntry{
+					Key:   "foo/update",
+					Value: []byte("new"),
+					RaftIndex: structs.RaftIndex{
+						ModifyIndex: 5,
+					},
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSGet,
+				DirEnt: structs.DirEntry{
+					Key: "foo/update",
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSGet,
+				DirEnt: structs.DirEntry{
+					Key: "not/there",
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSCheckIndex,
+				DirEnt: structs.DirEntry{
+					Key: "foo/update",
+					RaftIndex: structs.RaftIndex{
+						ModifyIndex: 8,
+					},
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSGet,
+				DirEnt: structs.DirEntry{
+					Key: "foo/lock",
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSLock,
+				DirEnt: structs.DirEntry{
+					Key:     "foo/lock",
+					Session: session,
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSCheckSession,
+				DirEnt: structs.DirEntry{
+					Key:     "foo/lock",
+					Session: session,
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSUnlock,
+				DirEnt: structs.DirEntry{
+					Key:     "foo/lock",
+					Session: session,
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSCheckSession,
+				DirEnt: structs.DirEntry{
+					Key:     "foo/lock",
+					Session: "",
+				},
+			},
+		},
+	}
+	results, errors := s.TxnRun(8, ops)
+	if len(errors) > 0 {
+		t.Fatalf("err: %v", errors)
+	}
+	if len(results) != len(ops) {
+		t.Fatalf("bad len: %d != %d", len(results), len(ops))
+	}
+
+	// Make sure the response looks as expected.
+	expected := structs.TxnResults{
+		&structs.TxnResult{
+			KVS: &structs.TxnKVSResult{
+				DirEnt: &structs.DirEntry{
+					Key: "foo/new",
+					RaftIndex: structs.RaftIndex{
+						CreateIndex: 8,
+						ModifyIndex: 8,
+					},
+				},
+			},
+		},
+		&structs.TxnResult{}, // delete
+		&structs.TxnResult{}, // delete tree
+		&structs.TxnResult{}, // delete CAS
+		&structs.TxnResult{
+			KVS: &structs.TxnKVSResult{
+				DirEnt: &structs.DirEntry{
+					Key:   "foo/update",
+					Value: []byte("stale"),
+					RaftIndex: structs.RaftIndex{
+						CreateIndex: 5,
+						ModifyIndex: 5,
+					},
+				},
+			},
+		},
+		&structs.TxnResult{
+			KVS: &structs.TxnKVSResult{
+				DirEnt: &structs.DirEntry{
+
+					Key: "foo/update",
+					RaftIndex: structs.RaftIndex{
+						CreateIndex: 5,
+						ModifyIndex: 5,
+					},
+				},
+			},
+		},
+		&structs.TxnResult{
+			KVS: &structs.TxnKVSResult{
+				DirEnt: &structs.DirEntry{
+					Key: "foo/update",
+					RaftIndex: structs.RaftIndex{
+						CreateIndex: 5,
+						ModifyIndex: 8,
+					},
+				},
+			},
+		},
+		&structs.TxnResult{
+			KVS: &structs.TxnKVSResult{
+				DirEnt: &structs.DirEntry{
+					Key:   "foo/update",
+					Value: []byte("new"),
+					RaftIndex: structs.RaftIndex{
+						CreateIndex: 5,
+						ModifyIndex: 8,
+					},
+				},
+			},
+		},
+		&structs.TxnResult{}, // get on not/there
+		&structs.TxnResult{
+			KVS: &structs.TxnKVSResult{
+				DirEnt: &structs.DirEntry{
+					Key: "foo/update",
+					RaftIndex: structs.RaftIndex{
+						CreateIndex: 5,
+						ModifyIndex: 8,
+					},
+				},
+			},
+		},
+		&structs.TxnResult{}, // get on foo/lock before it's created
+		&structs.TxnResult{
+			KVS: &structs.TxnKVSResult{
+				DirEnt: &structs.DirEntry{
+					Key:       "foo/lock",
+					Session:   session,
+					LockIndex: 1,
+					RaftIndex: structs.RaftIndex{
+						CreateIndex: 8,
+						ModifyIndex: 8,
+					},
+				},
+			},
+		},
+		&structs.TxnResult{
+			KVS: &structs.TxnKVSResult{
+				DirEnt: &structs.DirEntry{
+					Key:       "foo/lock",
+					Session:   session,
+					LockIndex: 1,
+					RaftIndex: structs.RaftIndex{
+						CreateIndex: 8,
+						ModifyIndex: 8,
+					},
+				},
+			},
+		},
+		&structs.TxnResult{
+			KVS: &structs.TxnKVSResult{
+				DirEnt: &structs.DirEntry{
+					Key:       "foo/lock",
+					LockIndex: 1,
+					RaftIndex: structs.RaftIndex{
+						CreateIndex: 8,
+						ModifyIndex: 8,
+					},
+				},
+			},
+		},
+		&structs.TxnResult{
+			KVS: &structs.TxnKVSResult{
+				DirEnt: &structs.DirEntry{
+					Key:       "foo/lock",
+					LockIndex: 1,
+					RaftIndex: structs.RaftIndex{
+						CreateIndex: 8,
+						ModifyIndex: 8,
+					},
+				},
+			},
+		},
+	}
+	if len(results) != len(expected) {
+		t.Fatalf("bad: %v", results)
+	}
+	for i, _ := range results {
+		if !reflect.DeepEqual(results[i], expected[i]) {
+			t.Fatalf("bad %d", i)
+		}
+	}
+
+	// Pull the resulting state store contents.
+	idx, actual, err := s.KVSList("")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if idx != 8 {
+		t.Fatalf("bad index: %d", idx)
+	}
+
+	// Make sure it looks as expected.
+	entries := structs.DirEntries{
+		&structs.DirEntry{
+			Key:       "foo/lock",
+			LockIndex: 1,
+			RaftIndex: structs.RaftIndex{
+				CreateIndex: 8,
+				ModifyIndex: 8,
+			},
+		},
+		&structs.DirEntry{
+			Key:   "foo/new",
+			Value: []byte("one"),
+			RaftIndex: structs.RaftIndex{
+				CreateIndex: 8,
+				ModifyIndex: 8,
+			},
+		},
+		&structs.DirEntry{
+			Key:   "foo/update",
+			Value: []byte("new"),
+			RaftIndex: structs.RaftIndex{
+				CreateIndex: 5,
+				ModifyIndex: 8,
+			},
+		},
+	}
+	if len(actual) != len(entries) {
+		t.Fatalf("bad len: %d != %d", len(actual), len(entries))
+	}
+	for i, _ := range actual {
+		if !reflect.DeepEqual(actual[i], entries[i]) {
+			t.Fatalf("bad %d", i)
+		}
+	}
+}
+
+func TestStateStore_Txn_KVS_Rollback(t *testing.T) {
+	s := testStateStore(t)
+
+	// Create kvs results in the state store.
+	testSetKey(t, s, 1, "foo/delete", "bar")
+	testSetKey(t, s, 2, "foo/update", "stale")
+
+	testRegisterNode(t, s, 3, "node1")
+	session := testUUID()
+	if err := s.SessionCreate(4, &structs.Session{ID: session, Node: "node1"}); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	ok, err := s.KVSLock(5, &structs.DirEntry{Key: "foo/lock", Value: []byte("foo"), Session: session})
+	if !ok || err != nil {
+		t.Fatalf("didn't get the lock: %v %s", ok, err)
+	}
+
+	bogus := testUUID()
+	if err := s.SessionCreate(6, &structs.Session{ID: bogus, Node: "node1"}); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	// This function verifies that the state store wasn't changed.
+	verifyStateStore := func(desc string) {
+		idx, actual, err := s.KVSList("")
+		if err != nil {
+			t.Fatalf("err (%s): %s", desc, err)
+		}
+		if idx != 5 {
+			t.Fatalf("bad index (%s): %d", desc, idx)
+		}
+
+		// Make sure it looks as expected.
+		entries := structs.DirEntries{
+			&structs.DirEntry{
+				Key:   "foo/delete",
+				Value: []byte("bar"),
+				RaftIndex: structs.RaftIndex{
+					CreateIndex: 1,
+					ModifyIndex: 1,
+				},
+			},
+			&structs.DirEntry{
+				Key:       "foo/lock",
+				Value:     []byte("foo"),
+				LockIndex: 1,
+				Session:   session,
+				RaftIndex: structs.RaftIndex{
+					CreateIndex: 5,
+					ModifyIndex: 5,
+				},
+			},
+			&structs.DirEntry{
+				Key:   "foo/update",
+				Value: []byte("stale"),
+				RaftIndex: structs.RaftIndex{
+					CreateIndex: 2,
+					ModifyIndex: 2,
+				},
+			},
+		}
+		if len(actual) != len(entries) {
+			t.Fatalf("bad len (%s): %d != %d", desc, len(actual), len(entries))
+		}
+		for i, _ := range actual {
+			if !reflect.DeepEqual(actual[i], entries[i]) {
+				t.Fatalf("bad (%s): op %d: %v != %v", desc, i, *(actual[i]), *(entries[i]))
+			}
+		}
+	}
+	verifyStateStore("initial")
+
+	// Set up a transaction that fails every operation.
+	ops := structs.TxnOps{
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSCAS,
+				DirEnt: structs.DirEntry{
+					Key:   "foo/update",
+					Value: []byte("new"),
+					RaftIndex: structs.RaftIndex{
+						ModifyIndex: 1,
+					},
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSLock,
+				DirEnt: structs.DirEntry{
+					Key:     "foo/lock",
+					Session: bogus,
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSUnlock,
+				DirEnt: structs.DirEntry{
+					Key:     "foo/lock",
+					Session: bogus,
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSCheckSession,
+				DirEnt: structs.DirEntry{
+					Key:     "foo/lock",
+					Session: bogus,
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSCheckSession,
+				DirEnt: structs.DirEntry{
+					Key:     "nope",
+					Session: bogus,
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSCheckIndex,
+				DirEnt: structs.DirEntry{
+					Key: "foo/lock",
+					RaftIndex: structs.RaftIndex{
+						ModifyIndex: 6,
+					},
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: structs.KVSCheckIndex,
+				DirEnt: structs.DirEntry{
+					Key: "nope",
+					RaftIndex: structs.RaftIndex{
+						ModifyIndex: 6,
+					},
+				},
+			},
+		},
+		&structs.TxnOp{
+			KVS: &structs.TxnKVSOp{
+				Verb: "nope",
+				DirEnt: structs.DirEntry{
+					Key: "foo/delete",
+				},
+			},
+		},
+	}
+	results, errors := s.TxnRun(7, ops)
+	if len(errors) != len(ops) {
+		t.Fatalf("bad len: %d != %d", len(errors), len(ops))
+	}
+	if len(results) != 0 {
+		t.Fatalf("bad len: %d != 0", len(results))
+	}
+	verifyStateStore("after")
+
+	// Make sure the errors look reasonable.
+	expected := []string{
+		"index is stale",
+		"lock is already held",
+		"lock isn't held, or is held by another session",
+		"current session",
+		`key "nope" doesn't exist`,
+		"current modify index",
+		`key "nope" doesn't exist`,
+		"unknown KVS verb",
+	}
+	if len(errors) != len(expected) {
+		t.Fatalf("bad len: %d != %d", len(errors), len(expected))
+	}
+	for i, msg := range expected {
+		if errors[i].OpIndex != i {
+			t.Fatalf("bad index: %d != %d", i, errors[i].OpIndex)
+		}
+		if !strings.Contains(errors[i].Error(), msg) {
+			t.Fatalf("bad %d: %v", i, errors[i].Error())
+		}
+	}
+}
+
+func TestStateStore_Txn_Watches(t *testing.T) {
+	s := testStateStore(t)
+
+	// Verify that a basic transaction triggers multiple watches. We call
+	// the same underlying methods that are called above so this is more
+	// of a sanity check.
+	verifyWatch(t, s.GetKVSWatch("multi/one"), func() {
+		verifyWatch(t, s.GetKVSWatch("multi/two"), func() {
+			ops := structs.TxnOps{
+				&structs.TxnOp{
+					KVS: &structs.TxnKVSOp{
+						Verb: structs.KVSSet,
+						DirEnt: structs.DirEntry{
+							Key:   "multi/one",
+							Value: []byte("one"),
+						},
+					},
+				},
+				&structs.TxnOp{
+					KVS: &structs.TxnKVSOp{
+						Verb: structs.KVSSet,
+						DirEnt: structs.DirEntry{
+							Key:   "multi/two",
+							Value: []byte("two"),
+						},
+					},
+				},
+			}
+			results, errors := s.TxnRun(15, ops)
+			if len(results) != len(ops) {
+				t.Fatalf("bad len: %d != %d", len(results), len(ops))
+			}
+			if len(errors) != 0 {
+				t.Fatalf("bad len: %d != 0", len(errors))
+			}
+		})
+	})
+
+	// Verify that a rolled back transaction doesn't trigger any watches.
+	verifyNoWatch(t, s.GetKVSWatch("multi/one"), func() {
+		verifyNoWatch(t, s.GetKVSWatch("multi/two"), func() {
+			ops := structs.TxnOps{
+				&structs.TxnOp{
+					KVS: &structs.TxnKVSOp{
+						Verb: structs.KVSSet,
+						DirEnt: structs.DirEntry{
+							Key:   "multi/one",
+							Value: []byte("one-updated"),
+						},
+					},
+				},
+				&structs.TxnOp{
+					KVS: &structs.TxnKVSOp{
+						Verb: structs.KVSSet,
+						DirEnt: structs.DirEntry{
+							Key:   "multi/two",
+							Value: []byte("two-updated"),
+						},
+					},
+				},
+				&structs.TxnOp{
+					KVS: &structs.TxnKVSOp{
+						Verb: structs.KVSLock,
+						DirEnt: structs.DirEntry{
+							Key:   "multi/nope",
+							Value: []byte("nope"),
+						},
+					},
+				},
+			}
+			results, errors := s.TxnRun(16, ops)
+			if len(errors) != 1 {
+				t.Fatalf("bad len: %d != 1", len(errors))
+			}
+			if len(results) != 0 {
+				t.Fatalf("bad len: %d != 0", len(results))
+			}
+		})
+	})
+}

consul/structs/structs.go

@@ -36,7 +36,7 @@ const (
 	TombstoneRequestType
 	CoordinateBatchUpdateType
 	PreparedQueryRequestType
-	KVSAtomicRequestType
+	TxnRequestType
 )
 
 const (
@@ -535,11 +535,11 @@ const (
 	KVSLock             = "lock"   // Lock a key
 	KVSUnlock           = "unlock" // Unlock a key
 
-	// KVSAtomic* operations are only available in KVSAtomicRequest
+	// The following operations are only available inside of atomic
-	// transactions.
+	// transactions via the Txn request.
-	KVSAtomicGet          = "get"           // Read the key during the transaction.
+	KVSGet          = "get"           // Read the key during the transaction.
-	KVSAtomicCheckSession = "check-session" // Check the session holds the key.
+	KVSCheckSession = "check-session" // Check the session holds the key.
-	KVSAtomicCheckIndex   = "check-index"   // Check the modify index of the key.
+	KVSCheckIndex   = "check-index"   // Check the modify index of the key.
 )
 
 // KVSRequest is used to operate on the Key-Value store
@@ -554,49 +554,6 @@ func (r *KVSRequest) RequestDatacenter() string {
 	return r.Datacenter
 }
 
-// KVSAtomicOp is used to define a single operation within an multi-key
-// transaction.
-type KVSAtomicOp struct {
-	Op     KVSOp
-	DirEnt DirEntry
-}
-
-// KVSAtomicOps is a list of atomic operations.
-type KVSAtomicOps []*KVSAtomicOp
-
-// KVSAtomicRequest is used to perform atomic multi-key operations on the
-// Key-Value store.
-type KVSAtomicRequest struct {
-	Datacenter string
-	Ops        KVSAtomicOps
-	WriteRequest
-}
-
-func (r *KVSAtomicRequest) RequestDatacenter() string {
-	return r.Datacenter
-}
-
-// KVSAtomicError is used to return information about an error for a specific
-// operation.
-type KVSAtomicError struct {
-	OpIndex int
-	What    string
-}
-
-// Error returns the string representation of an atomic error.
-func (e KVSAtomicError) Error() string {
-	return fmt.Sprintf("op %d: %s", e.OpIndex, e.What)
-}
-
-// KVSAtomicErrors is a list of KVSAtomicError entries.
-type KVSAtomicErrors []*KVSAtomicError
-
-// KVSAtomicResponse is the structure returned by a KVSAtomicRequest.
-type KVSAtomicResponse struct {
-	Errors  KVSAtomicErrors
-	Results DirEntries
-}
-
 // KeyRequest is used to request a key, or key prefix
 type KeyRequest struct {
 	Datacenter string

consul/structs/txn.go

@@ -0,0 +1,69 @@
+package structs
+
+import (
+	"fmt"
+)
+
+// TxnKVSOp is used to define a single operation on the KVS inside a
+// transaction
+type TxnKVSOp struct {
+	Verb   KVSOp
+	DirEnt DirEntry
+}
+
+// TxnKVSResult is used to define the result of a single operation on the KVS
+// inside a transaction.
+type TxnKVSResult struct {
+	DirEnt *DirEntry
+}
+
+// TxnOp is used to define a single operation inside a transaction. Only one
+// of the types should be filled out per entry.
+type TxnOp struct {
+	KVS *TxnKVSOp
+}
+
+// TxnOps is a list of operations within a transaction.
+type TxnOps []*TxnOp
+
+// TxnRequest is used to apply multiple operations to the state store in a
+// single transaction
+type TxnRequest struct {
+	Datacenter string
+	Ops        TxnOps
+	WriteRequest
+}
+
+func (r *TxnRequest) RequestDatacenter() string {
+	return r.Datacenter
+}
+
+// TxnError is used to return information about an error for a specific
+// operation.
+type TxnError struct {
+	OpIndex int
+	What    string
+}
+
+// Error returns the string representation of an atomic error.
+func (e TxnError) Error() string {
+	return fmt.Sprintf("op %d: %s", e.OpIndex, e.What)
+}
+
+// TxnErrors is a list of TxnError entries.
+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 {
+	KVS *TxnKVSResult
+}
+
+// TxnResults is a list of TxnResult entries.
+type TxnResults []*TxnResult
+
+// TxnResponse is the structure returned by a TxnRequest.
+type TxnResponse struct {
+	Results TxnResults
+	Errors  TxnErrors
+}

consul/txn_endpoint.go

@@ -14,24 +14,26 @@ type Txn struct {
 }
 
 // Apply is used to apply multiple operations in a single, atomic transaction.
-func (t *Txn) Apply(args *structs.KVSAtomicRequest, reply *structs.KVSAtomicResponse) error {
+func (t *Txn) Apply(args *structs.TxnRequest, reply *structs.TxnResponse) error {
 	if done, err := t.srv.forward("Txn.Apply", args, args, reply); done {
 		return err
 	}
 	defer metrics.MeasureSince([]string{"consul", "txn", "apply"}, time.Now())
 
-	// Perform the pre-apply checks on each of the operations.
+	// Perform the pre-apply checks for any KVS operations.
 	acl, err := t.srv.resolveToken(args.Token)
 	if err != nil {
 		return err
 	}
 	for i, op := range args.Ops {
-		ok, err := kvsPreApply(t.srv, acl, op.Op, &op.DirEnt)
+		if op.KVS != nil {
-		if err != nil {
+			ok, err := kvsPreApply(t.srv, acl, op.KVS.Verb, &op.KVS.DirEnt)
-			reply.Errors = append(reply.Errors, &structs.KVSAtomicError{i, err.Error()})
+			if err != nil {
-		} else if !ok {
+				reply.Errors = append(reply.Errors, &structs.TxnError{i, err.Error()})
-			err = fmt.Errorf("failed to lock key %q due to lock delay", op.DirEnt.Key)
+			} else if !ok {
-			reply.Errors = append(reply.Errors, &structs.KVSAtomicError{i, err.Error()})
+				err = fmt.Errorf("failed to lock key %q due to lock delay", op.KVS.DirEnt.Key)
+				reply.Errors = append(reply.Errors, &structs.TxnError{i, err.Error()})
+			}
 		}
 	}
 	if len(reply.Errors) > 0 {
@@ -39,9 +41,9 @@ func (t *Txn) Apply(args *structs.KVSAtomicRequest, reply *structs.KVSAtomicResp
 	}
 
 	// Apply the update.
-	resp, err := t.srv.raftApply(structs.KVSAtomicRequestType, args)
+	resp, err := t.srv.raftApply(structs.TxnRequestType, args)
 	if err != nil {
-		t.srv.logger.Printf("[ERR] consul.kvs: ApplyAtomic failed: %v", err)
+		t.srv.logger.Printf("[ERR] consul.txn: Apply failed: %v", err)
 		return err
 	}
 	if respErr, ok := resp.(error); ok {
@@ -50,8 +52,8 @@ func (t *Txn) Apply(args *structs.KVSAtomicRequest, reply *structs.KVSAtomicResp
 
 	// Convert the return type. This should be a cheap copy since we are
 	// just taking the two slices.
-	if respAtomic, ok := resp.(structs.KVSAtomicResponse); ok {
+	if txnResp, ok := resp.(structs.TxnResponse); ok {
-		*reply = respAtomic
+		*reply = txnResp
 	} else {
 		return fmt.Errorf("unexpected return type %T", resp)
 	}

consul/txn_endpoint_test.go

@@ -25,26 +25,30 @@ func TestTxn_Apply(t *testing.T) {
 	// Do a super basic request. The state store test covers the details so
 	// we just need to be sure that the transaction is sent correctly and
 	// the results are converted appropriately.
-	arg := structs.KVSAtomicRequest{
+	arg := structs.TxnRequest{
 		Datacenter: "dc1",
-		Ops: structs.KVSAtomicOps{
+		Ops: structs.TxnOps{
-			&structs.KVSAtomicOp{
+			&structs.TxnOp{
-				Op: structs.KVSSet,
+				KVS: &structs.TxnKVSOp{
-				DirEnt: structs.DirEntry{
+					Verb: structs.KVSSet,
-					Key:   "test",
+					DirEnt: structs.DirEntry{
-					Flags: 42,
+						Key:   "test",
-					Value: []byte("test"),
+						Flags: 42,
+						Value: []byte("test"),
+					},
 				},
 			},
-			&structs.KVSAtomicOp{
+			&structs.TxnOp{
-				Op: structs.KVSAtomicGet,
+				KVS: &structs.TxnKVSOp{
-				DirEnt: structs.DirEntry{
+					Verb: structs.KVSGet,
-					Key: "test",
+					DirEnt: structs.DirEntry{
+						Key: "test",
+					},
 				},
 			},
 		},
 	}
-	var out structs.KVSAtomicResponse
+	var out structs.TxnResponse
 	if err := msgpackrpc.CallWithCodec(codec, "Txn.Apply", &arg, &out); err != nil {
 		t.Fatalf("err: %v", err)
 	}
@@ -64,24 +68,32 @@ func TestTxn_Apply(t *testing.T) {
 	}
 
 	// Verify the transaction's return value.
-	expected := structs.KVSAtomicResponse{
+	expected := structs.TxnResponse{
-		Results: structs.DirEntries{
+		Results: structs.TxnResults{
-			&structs.DirEntry{
+			&structs.TxnResult{
-				Key:   "test",
+				KVS: &structs.TxnKVSResult{
-				Flags: 42,
+					DirEnt: &structs.DirEntry{
-				Value: nil,
+						Key:   "test",
-				RaftIndex: structs.RaftIndex{
+						Flags: 42,
-					CreateIndex: d.CreateIndex,
+						Value: nil,
-					ModifyIndex: d.ModifyIndex,
+						RaftIndex: structs.RaftIndex{
+							CreateIndex: d.CreateIndex,
+							ModifyIndex: d.ModifyIndex,
+						},
+					},
 				},
 			},
-			&structs.DirEntry{
+			&structs.TxnResult{
-				Key:   "test",
+				KVS: &structs.TxnKVSResult{
-				Flags: 42,
+					DirEnt: &structs.DirEntry{
-				Value: []byte("test"),
+						Key:   "test",
-				RaftIndex: structs.RaftIndex{
+						Flags: 42,
-					CreateIndex: d.CreateIndex,
+						Value: []byte("test"),
-					ModifyIndex: d.ModifyIndex,
+						RaftIndex: structs.RaftIndex{
+							CreateIndex: d.CreateIndex,
+							ModifyIndex: d.ModifyIndex,
+						},
+					},
 				},
 			},
 		},
@@ -124,81 +136,101 @@ func TestTxn_Apply_ACLDeny(t *testing.T) {
 
 	// Set up a transaction where every operation should get blocked due to
 	// ACLs.
-	arg := structs.KVSAtomicRequest{
+	arg := structs.TxnRequest{
 		Datacenter: "dc1",
-		Ops: structs.KVSAtomicOps{
+		Ops: structs.TxnOps{
-			&structs.KVSAtomicOp{
+			&structs.TxnOp{
-				Op: structs.KVSSet,
+				KVS: &structs.TxnKVSOp{
-				DirEnt: structs.DirEntry{
+					Verb: structs.KVSSet,
-					Key: "foo",
+					DirEnt: structs.DirEntry{
+						Key: "foo",
+					},
 				},
 			},
-			&structs.KVSAtomicOp{
+			&structs.TxnOp{
-				Op: structs.KVSDelete,
+				KVS: &structs.TxnKVSOp{
-				DirEnt: structs.DirEntry{
+					Verb: structs.KVSDelete,
-					Key: "foo",
+					DirEnt: structs.DirEntry{
+						Key: "foo",
+					},
 				},
 			},
-			&structs.KVSAtomicOp{
+			&structs.TxnOp{
-				Op: structs.KVSDeleteCAS,
+				KVS: &structs.TxnKVSOp{
-				DirEnt: structs.DirEntry{
+					Verb: structs.KVSDeleteCAS,
-					Key: "foo",
+					DirEnt: structs.DirEntry{
+						Key: "foo",
+					},
 				},
 			},
-			&structs.KVSAtomicOp{
+			&structs.TxnOp{
-				Op: structs.KVSDeleteTree,
+				KVS: &structs.TxnKVSOp{
-				DirEnt: structs.DirEntry{
+					Verb: structs.KVSDeleteTree,
-					Key: "foo",
+					DirEnt: structs.DirEntry{
+						Key: "foo",
+					},
 				},
 			},
-			&structs.KVSAtomicOp{
+			&structs.TxnOp{
-				Op: structs.KVSCAS,
+				KVS: &structs.TxnKVSOp{
-				DirEnt: structs.DirEntry{
+					Verb: structs.KVSCAS,
-					Key: "foo",
+					DirEnt: structs.DirEntry{
+						Key: "foo",
+					},
 				},
 			},
-			&structs.KVSAtomicOp{
+			&structs.TxnOp{
-				Op: structs.KVSLock,
+				KVS: &structs.TxnKVSOp{
-				DirEnt: structs.DirEntry{
+					Verb: structs.KVSLock,
-					Key: "foo",
+					DirEnt: structs.DirEntry{
+						Key: "foo",
+					},
 				},
 			},
-			&structs.KVSAtomicOp{
+			&structs.TxnOp{
-				Op: structs.KVSUnlock,
+				KVS: &structs.TxnKVSOp{
-				DirEnt: structs.DirEntry{
+					Verb: structs.KVSUnlock,
-					Key: "foo",
+					DirEnt: structs.DirEntry{
+						Key: "foo",
+					},
 				},
 			},
-			&structs.KVSAtomicOp{
+			&structs.TxnOp{
-				Op: structs.KVSAtomicGet,
+				KVS: &structs.TxnKVSOp{
-				DirEnt: structs.DirEntry{
+					Verb: structs.KVSGet,
-					Key: "nope",
+					DirEnt: structs.DirEntry{
+						Key: "nope",
+					},
 				},
 			},
-			&structs.KVSAtomicOp{
+			&structs.TxnOp{
-				Op: structs.KVSAtomicCheckSession,
+				KVS: &structs.TxnKVSOp{
-				DirEnt: structs.DirEntry{
+					Verb: structs.KVSCheckSession,
-					Key: "nope",
+					DirEnt: structs.DirEntry{
+						Key: "nope",
+					},
 				},
 			},
-			&structs.KVSAtomicOp{
+			&structs.TxnOp{
-				Op: structs.KVSAtomicCheckIndex,
+				KVS: &structs.TxnKVSOp{
-				DirEnt: structs.DirEntry{
+					Verb: structs.KVSCheckIndex,
-					Key: "nope",
+					DirEnt: structs.DirEntry{
+						Key: "nope",
+					},
 				},
 			},
 		},
 		WriteRequest: structs.WriteRequest{Token: id},
 	}
-	var out structs.KVSAtomicResponse
+	var out structs.TxnResponse
 	if err := msgpackrpc.CallWithCodec(codec, "Txn.Apply", &arg, &out); err != nil {
 		t.Fatalf("err: %v", err)
 	}
 
 	// Verify the transaction's return value.
-	var expected structs.KVSAtomicResponse
+	var expected structs.TxnResponse
 	for i, _ := range arg.Ops {
-		expected.Errors = append(expected.Errors, &structs.KVSAtomicError{i, permissionDeniedErr.Error()})
+		expected.Errors = append(expected.Errors, &structs.TxnError{i, permissionDeniedErr.Error()})
 	}
 	if !reflect.DeepEqual(out, expected) {
 		t.Fatalf("bad %v", out)
@@ -245,20 +277,22 @@ func TestTxn_Apply_LockDelay(t *testing.T) {
 	validId := session.ID
 
 	// Make a lock request via an atomic transaction.
-	arg := structs.KVSAtomicRequest{
+	arg := structs.TxnRequest{
 		Datacenter: "dc1",
-		Ops: structs.KVSAtomicOps{
+		Ops: structs.TxnOps{
-			&structs.KVSAtomicOp{
+			&structs.TxnOp{
-				Op: structs.KVSLock,
+				KVS: &structs.TxnKVSOp{
-				DirEnt: structs.DirEntry{
+					Verb: structs.KVSLock,
-					Key:     "test",
+					DirEnt: structs.DirEntry{
-					Session: validId,
+						Key:     "test",
+						Session: validId,
+					},
 				},
 			},
 		},
 	}
 	{
-		var out structs.KVSAtomicResponse
+		var out structs.TxnResponse
 		if err := msgpackrpc.CallWithCodec(codec, "Txn.Apply", &arg, &out); err != nil {
 			t.Fatalf("err: %v", err)
 		}
@@ -275,13 +309,13 @@ func TestTxn_Apply_LockDelay(t *testing.T) {
 
 	// Should acquire.
 	{
-		var out structs.KVSAtomicResponse
+		var out structs.TxnResponse
 		if err := msgpackrpc.CallWithCodec(codec, "Txn.Apply", &arg, &out); err != nil {
 			t.Fatalf("err: %v", err)
 		}
 		if len(out.Results) != 1 ||
 			len(out.Errors) != 0 ||
-			out.Results[0].LockIndex != 2 {
+			out.Results[0].KVS.DirEnt.LockIndex != 2 {
 			t.Fatalf("bad: %v", out)
 		}
 	}