Ephemeral Nodes for via Session behavior settings.

command/agent/session_endpoint.go

@@ -32,13 +32,14 @@ func (s *HTTPServer) SessionCreate(resp http.ResponseWriter, req *http.Request)
 		return nil, nil
 	}
 
-	// Default the session to our node + serf check
+	// Default the session to our node + serf check + release session invalidate behavior
 	args := structs.SessionRequest{
 		Op: structs.SessionCreate,
 		Session: structs.Session{
 			Node:      s.agent.config.NodeName,
 			Checks:    []string{consul.SerfCheckID},
 			LockDelay: 15 * time.Second,
+			Behavior:  structs.SessionKeysRelease,
 		},
 	}
 	s.parseDC(req, &args.Datacenter)

command/agent/session_endpoint_test.go

@@ -59,6 +59,55 @@ func TestSessionCreate(t *testing.T) {
 	})
 }
 
+func TestSessionCreateDelete(t *testing.T) {
+	httpTest(t, func(srv *HTTPServer) {
+		// Create a health check
+		args := &structs.RegisterRequest{
+			Datacenter: "dc1",
+			Node:       srv.agent.config.NodeName,
+			Address:    "127.0.0.1",
+			Check: &structs.HealthCheck{
+				CheckID:   "consul",
+				Node:      srv.agent.config.NodeName,
+				Name:      "consul",
+				ServiceID: "consul",
+				Status:    structs.HealthPassing,
+			},
+		}
+		var out struct{}
+		if err := srv.agent.RPC("Catalog.Register", args, &out); err != nil {
+			t.Fatalf("err: %v", err)
+		}
+
+		// Associate session with node and 2 health checks, and make it delete on session destroy
+		body := bytes.NewBuffer(nil)
+		enc := json.NewEncoder(body)
+		raw := map[string]interface{}{
+			"Name":      "my-cool-session",
+			"Node":      srv.agent.config.NodeName,
+			"Checks":    []string{consul.SerfCheckID, "consul"},
+			"LockDelay": "20s",
+			"Behavior":  structs.SessionKeysDelete,
+		}
+		enc.Encode(raw)
+
+		req, err := http.NewRequest("PUT", "/v1/session/create", body)
+		if err != nil {
+			t.Fatalf("err: %v", err)
+		}
+
+		resp := httptest.NewRecorder()
+		obj, err := srv.SessionCreate(resp, req)
+		if err != nil {
+			t.Fatalf("err: %v", err)
+		}
+
+		if _, ok := obj.(sessionCreateResponse); !ok {
+			t.Fatalf("should work")
+		}
+	})
+}
+
 func TestFixupLockDelay(t *testing.T) {
 	inp := map[string]interface{}{
 		"lockdelay": float64(15),
@@ -105,6 +154,28 @@ func makeTestSession(t *testing.T, srv *HTTPServer) string {
 	return sessResp.ID
 }
 
+func makeTestSessionDelete(t *testing.T, srv *HTTPServer) string {
+	// Create Session with delete behavior
+	body := bytes.NewBuffer(nil)
+	enc := json.NewEncoder(body)
+	raw := map[string]interface{}{
+		"Behavior": "delete",
+	}
+	enc.Encode(raw)
+
+	req, err := http.NewRequest("PUT", "/v1/session/create", body)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	resp := httptest.NewRecorder()
+	obj, err := srv.SessionCreate(resp, req)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	sessResp := obj.(sessionCreateResponse)
+	return sessResp.ID
+}
+
 func TestSessionDestroy(t *testing.T) {
 	httpTest(t, func(srv *HTTPServer) {
 		id := makeTestSession(t, srv)
@@ -188,3 +259,45 @@ func TestSessionsForNode(t *testing.T) {
 		}
 	})
 }
+
+func TestSessionDeleteDestroy(t *testing.T) {
+	httpTest(t, func(srv *HTTPServer) {
+		id := makeTestSessionDelete(t, srv)
+
+		// now create a new key for the session and acquire it
+		buf := bytes.NewBuffer([]byte("test"))
+		req, err := http.NewRequest("PUT", "/v1/kv/ephemeral?acquire="+id, buf)
+		if err != nil {
+			t.Fatalf("err: %v", err)
+		}
+		resp := httptest.NewRecorder()
+		obj, err := srv.KVSEndpoint(resp, req)
+		if err != nil {
+			t.Fatalf("err: %v", err)
+		}
+
+		if res := obj.(bool); !res {
+			t.Fatalf("should work")
+		}
+
+		// now destroy the session, this should delete the key created above
+		req, err = http.NewRequest("PUT", "/v1/session/destroy/"+id, nil)
+		resp = httptest.NewRecorder()
+		obj, err = srv.SessionDestroy(resp, req)
+		if err != nil {
+			t.Fatalf("err: %v", err)
+		}
+		if resp := obj.(bool); !resp {
+			t.Fatalf("should work")
+		}
+
+		// Verify that the key is gone
+		req, _ = http.NewRequest("GET", "/v1/kv/ephemeral", nil)
+		resp = httptest.NewRecorder()
+		obj, _ = srv.KVSEndpoint(resp, req)
+		res, found := obj.(structs.DirEntries)
+		if found || len(res) != 0 {
+			t.Fatalf("bad: %v found, should be nothing", res)
+		}
+	})
+}

consul/session_endpoint.go

@@ -28,6 +28,14 @@ func (s *Session) Apply(args *structs.SessionRequest, reply *string) error {
 	if args.Session.Node == "" && args.Op == structs.SessionCreate {
 		return fmt.Errorf("Must provide Node")
 	}
+	switch args.Session.Behavior {
+	case structs.SessionKeysRelease, structs.SessionKeysDelete:
+		// we like it, use it
+	case "":
+		args.Session.Behavior = structs.SessionKeysRelease // force default behavior
+	default:
+		return fmt.Errorf("Invalid Behavior setting '%s'", args.Session.Behavior)
+	}
 
 	// If this is a create, we must generate the Session ID. This must
 	// be done prior to appending to the raft log, because the ID is not

consul/session_endpoint_test.go

@@ -66,6 +66,69 @@ func TestSessionEndpoint_Apply(t *testing.T) {
 	}
 }
 
+func TestSessionEndpoint_DeleteApply(t *testing.T) {
+	dir1, s1 := testServer(t)
+	defer os.RemoveAll(dir1)
+	defer s1.Shutdown()
+	client := rpcClient(t, s1)
+	defer client.Close()
+
+	testutil.WaitForLeader(t, client.Call, "dc1")
+
+	// Just add a node
+	s1.fsm.State().EnsureNode(1, structs.Node{"foo", "127.0.0.1"})
+
+	arg := structs.SessionRequest{
+		Datacenter: "dc1",
+		Op:         structs.SessionCreate,
+		Session: structs.Session{
+			Node:     "foo",
+			Name:     "my-session",
+			Behavior: structs.SessionKeysDelete,
+		},
+	}
+	var out string
+	if err := client.Call("Session.Apply", &arg, &out); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	id := out
+
+	// Verify
+	state := s1.fsm.State()
+	_, s, err := state.SessionGet(out)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if s == nil {
+		t.Fatalf("should not be nil")
+	}
+	if s.Node != "foo" {
+		t.Fatalf("bad: %v", s)
+	}
+	if s.Name != "my-session" {
+		t.Fatalf("bad: %v", s)
+	}
+	if s.Behavior != structs.SessionKeysDelete {
+		t.Fatalf("bad: %v", s)
+	}
+
+	// Do a delete
+	arg.Op = structs.SessionDestroy
+	arg.Session.ID = out
+	if err := client.Call("Session.Apply", &arg, &out); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// Verify
+	_, s, err = state.SessionGet(id)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if s != nil {
+		t.Fatalf("bad: %v", s)
+	}
+}
+
 func TestSessionEndpoint_Get(t *testing.T) {
 	dir1, s1 := testServer(t)
 	defer os.RemoveAll(dir1)

consul/state_store.go

@@ -1327,6 +1327,15 @@ func (s *StateStore) SessionCreate(index uint64, session *structs.Session) error
 		return fmt.Errorf("Missing Session ID")
 	}
 
+	switch session.Behavior {
+	case structs.SessionKeysRelease, structs.SessionKeysDelete:
+		// we like
+	case "":
+		session.Behavior = structs.SessionKeysRelease // force default behavior
+	default:
+		return fmt.Errorf("Invalid Session Behavior setting '%s'", session.Behavior)
+	}
+
 	// Assign the create index
 	session.CreateIndex = index
 
@@ -1454,7 +1463,7 @@ func (s *StateStore) SessionDestroy(index uint64, id string) error {
 	}
 	defer tx.Abort()
 
-	log.Printf("[DEBUG] consul.state: Invalidating session %s due to session destroy",
+	s.logger.Printf("[DEBUG] consul.state: Invalidating session %s due to session destroy",
 		id)
 	if err := s.invalidateSession(index, tx, id); err != nil {
 		return err
@@ -1471,7 +1480,7 @@ func (s *StateStore) invalidateNode(index uint64, tx *MDBTxn, node string) error
 	}
 	for _, sess := range sessions {
 		session := sess.(*structs.Session).ID
-		log.Printf("[DEBUG] consul.state: Invalidating session %s due to node '%s' invalidation",
+		s.logger.Printf("[DEBUG] consul.state: Invalidating session %s due to node '%s' invalidation",
 			session, node)
 		if err := s.invalidateSession(index, tx, session); err != nil {
 			return err
@@ -1489,7 +1498,7 @@ func (s *StateStore) invalidateCheck(index uint64, tx *MDBTxn, node, check strin
 	}
 	for _, sc := range sessionChecks {
 		session := sc.(*sessionCheck).Session
-		log.Printf("[DEBUG] consul.state: Invalidating session %s due to check '%s' invalidation",
+		s.logger.Printf("[DEBUG] consul.state: Invalidating session %s due to check '%s' invalidation",
 			session, check)
 		if err := s.invalidateSession(index, tx, session); err != nil {
 			return err
@@ -1513,15 +1522,23 @@ func (s *StateStore) invalidateSession(index uint64, tx *MDBTxn, id string) erro
 	}
 	session := res[0].(*structs.Session)
 
-	// Enforce the MaxLockDelay
-	delay := session.LockDelay
-	if delay > structs.MaxLockDelay {
-		delay = structs.MaxLockDelay
-	}
+	if session.Behavior == structs.SessionKeysDelete {
+		// delete the keys held by the session
+		if err := s.deleteKeys(index, tx, id); err != nil {
+			return err
+		}
 
-	// Invalidate any held locks
-	if err := s.invalidateLocks(index, tx, delay, id); err != nil {
-		return err
+	} else { // default to release
+		// Enforce the MaxLockDelay
+		delay := session.LockDelay
+		if delay > structs.MaxLockDelay {
+			delay = structs.MaxLockDelay
+		}
+
+		// Invalidate any held locks
+		if err := s.invalidateLocks(index, tx, delay, id); err != nil {
+			return err
+		}
 	}
 
 	// Nuke the session
@@ -1588,6 +1605,23 @@ func (s *StateStore) invalidateLocks(index uint64, tx *MDBTxn,
 	return nil
 }
 
+// deleteKeys is used to delete all the keys created by a session
+// within a given txn. All tables should be locked in the tx.
+func (s *StateStore) deleteKeys(index uint64, tx *MDBTxn, id string) error {
+	num, err := s.kvsTable.DeleteTxn(tx, "session", id)
+	if err != nil {
+		return err
+	}
+
+	if num > 0 {
+		if err := s.kvsTable.SetLastIndexTxn(tx, index); err != nil {
+			return err
+		}
+		tx.Defer(func() { s.watch[s.kvsTable].Notify() })
+	}
+	return nil
+}
+
 // ACLSet is used to create or update an ACL entry
 func (s *StateStore) ACLSet(index uint64, acl *structs.ACL) error {
 	// Check for an ID

consul/state_store_test.go

@@ -2279,6 +2279,53 @@ func TestSessionInvalidate_KeyUnlock(t *testing.T) {
 	}
 }
 
+func TestSessionInvalidate_KeyDelete(t *testing.T) {
+	store, err := testStateStore()
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	defer store.Close()
+
+	if err := store.EnsureNode(3, structs.Node{"foo", "127.0.0.1"}); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	session := &structs.Session{
+		ID:        generateUUID(),
+		Node:      "foo",
+		LockDelay: 50 * time.Millisecond,
+		Behavior:  structs.SessionKeysDelete,
+	}
+	if err := store.SessionCreate(4, session); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// Lock a key with the session
+	d := &structs.DirEntry{
+		Key:     "/bar",
+		Flags:   42,
+		Value:   []byte("test"),
+		Session: session.ID,
+	}
+	ok, err := store.KVSLock(5, d)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if !ok {
+		t.Fatalf("unexpected fail")
+	}
+
+	// Delete the node
+	if err := store.DeleteNode(6, "foo"); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// Key should be deleted
+	_, d2, err := store.KVSGet("/bar")
+	if d2 != nil {
+		t.Fatalf("unexpected undeleted key")
+	}
+}
+
 func TestACLSet_Get(t *testing.T) {
 	store, err := testStateStore()
 	if err != nil {