Issue 2277: Add strict schema mode (#2863)

Fixes #2277.

* Add --mutations option.

* Check strict mode and schema before allowing mutation.

* Remove --nomutations option.

* Add tests of strict schema with multi-group cluster.

* Refactor out code duplicated in proposeOrSend() and Mutate().

* Log message when server is ready to accept requests.

* Check for error instead of predicate type to detect undefined predicates.

* Replace nomutations test with mutations_mode test.

dgraph/cmd/alpha/mutations_mode/docker-compose.yml

@@ -0,0 +1,104 @@
+# This file sets up the cluster required by the tests in this directory.
+version: "3.5"
+services:
+  zero1:
+    image: dgraph/dgraph:latest
+    container_name: bank-dg0.1
+    working_dir: /data/dg0.1
+    ports:
+      - 5080:5080
+      - 6080:6080
+    labels:
+      cluster: test
+    volumes:
+      - type: bind
+        source: $GOPATH/bin
+        target: /gobin
+        read_only: true
+    command: /gobin/dgraph zero -o 0 --my=zero1:5080 --replicas 1 --idx 1 --logtostderr
+
+  zero2:
+    image: dgraph/dgraph:latest
+    container_name: bank-dg0.2
+    depends_on:
+      - zero1
+    ports:
+      - 5082:5082
+      - 6082:6082
+    labels:
+      cluster: test
+    volumes:
+      - type: bind
+        source: $GOPATH/bin
+        target: /gobin
+        read_only: true
+    command: /gobin/dgraph zero -o 2 --my=zero2:5082 --replicas 1 --idx 2 --logtostderr --peer=zero1:5080
+
+  zero3:
+    image: dgraph/dgraph:latest
+    container_name: bank-dg0.3
+    depends_on:
+      - zero2
+    ports:
+      - 5083:5083
+      - 6083:6083
+    labels:
+      cluster: test
+    volumes:
+      - type: bind
+        source: $GOPATH/bin
+        target: /gobin
+        read_only: true
+    command: /gobin/dgraph zero -o 3 --my=zero3:5083 --replicas 1 --idx 3 --logtostderr --peer=zero1:5080
+
+  dg1:
+    image: dgraph/dgraph:latest
+    container_name: bank-dg1
+    working_dir: /data/dg1
+    volumes:
+      - type: bind
+        source: $GOPATH/bin
+        target: /gobin
+        read_only: true
+    ports:
+      - 8180:8180
+      - 9180:9180
+    labels:
+      cluster: test
+    command: /gobin/dgraph alpha --my=dg1:7180 --lru_mb=1024 --zero=zero1:5080 -o 100 --logtostderr --mutations=disallow
+
+  dg2:
+    image: dgraph/dgraph:latest
+    container_name: bank-dg2
+    working_dir: /data/dg2
+    depends_on:
+      - dg1
+    volumes:
+      - type: bind
+        source: $GOPATH/bin
+        target: /gobin
+        read_only: true
+    ports:
+      - 8182:8182
+      - 9182:9182
+    labels:
+      cluster: test
+    command: /gobin/dgraph alpha --my=dg2:7182 --lru_mb=1024 --zero=zero1:5080 -o 102 --logtostderr --mutations=strict
+
+  dg3:
+    image: dgraph/dgraph:latest
+    container_name: bank-dg3
+    working_dir: /data/dg3
+    depends_on:
+      - dg2
+    volumes:
+      - type: bind
+        source: $GOPATH/bin
+        target: /gobin
+        read_only: true
+    ports:
+      - 8183:8183
+      - 9183:9183
+    labels:
+      cluster: test
+    command: /gobin/dgraph alpha --my=dg3:7183 --lru_mb=1024 --zero=zero1:5080 -o 103 --logtostderr --mutations=strict

dgraph/cmd/alpha/mutations_mode/mutations_mode_test.go

@@ -0,0 +1,204 @@
+/*
+ * Copyright 2017-2018 Dgraph Labs, Inc. and Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package main
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"github.com/dgraph-io/dgo"
+	"github.com/dgraph-io/dgo/protos/api"
+	"github.com/dgraph-io/dgraph/x"
+	"github.com/stretchr/testify/require"
+
+	"google.golang.org/grpc"
+)
+
+// Tests in this file require a cluster running with the --mutations=<mode> option.
+
+const disallowModeAlpha = "localhost:9180"
+const strictModeAlphaGroup1 = "localhost:9182"
+const strictModeAlphaGroup2 = "localhost:9183"
+
+func runOn(conn *grpc.ClientConn, fn func(*testing.T, *dgo.Dgraph)) func(*testing.T) {
+	return func(t *testing.T) {
+		dg := dgo.NewDgraphClient(api.NewDgraphClient(conn))
+		fn(t, dg)
+	}
+}
+
+func dropAllDisallowed(t *testing.T, dg *dgo.Dgraph) {
+	err := dg.Alter(context.Background(), &api.Operation{DropAll: true})
+
+	require.Error(t, err)
+	require.Contains(t, strings.ToLower(err.Error()), "no mutations allowed")
+}
+
+func dropAllAllowed(t *testing.T, dg *dgo.Dgraph) {
+	err := dg.Alter(context.Background(), &api.Operation{DropAll: true})
+
+	require.NoError(t, err)
+}
+
+func mutateNewDisallowed(t *testing.T, dg *dgo.Dgraph) {
+	ctx := context.Background()
+
+	txn := dg.NewTxn()
+	_, err := txn.Mutate(ctx, &api.Mutation{
+		SetNquads: []byte(`
+			_:a <name> "Alice" .
+		`),
+	})
+
+	require.Error(t, err)
+	require.Contains(t, strings.ToLower(err.Error()), "no mutations allowed")
+}
+
+func mutateNewDisallowed2(t *testing.T, dg *dgo.Dgraph) {
+	ctx := context.Background()
+
+	txn := dg.NewTxn()
+	_, err := txn.Mutate(ctx, &api.Mutation{
+		SetNquads: []byte(`
+			_:a <name> "Alice" .
+		`),
+	})
+
+	require.Error(t, err)
+	require.Contains(t, strings.ToLower(err.Error()), "schema not defined for predicate")
+}
+
+func addPredicateDisallowed(t *testing.T, dg *dgo.Dgraph) {
+	ctx := context.Background()
+
+	err := dg.Alter(ctx, &api.Operation{
+		Schema: `name: string @index(exact) .`,
+	})
+
+	require.Error(t, err)
+	require.Contains(t, strings.ToLower(err.Error()), "no mutations allowed")
+}
+
+func addPredicateAllowed1(t *testing.T, dg *dgo.Dgraph) {
+	ctx := context.Background()
+
+	err := dg.Alter(ctx, &api.Operation{
+		Schema: `name: string @index(exact) .`,
+	})
+
+	require.NoError(t, err)
+}
+
+func addPredicateAllowed2(t *testing.T, dg *dgo.Dgraph) {
+	ctx := context.Background()
+
+	err := dg.Alter(ctx, &api.Operation{
+		Schema: `size: string @index(exact) .`,
+	})
+
+	require.NoError(t, err)
+}
+
+func mutateExistingDisallowed(t *testing.T, dg *dgo.Dgraph) {
+	ctx := context.Background()
+
+	txn := dg.NewTxn()
+	_, err := txn.Mutate(ctx, &api.Mutation{
+		SetNquads: []byte(`
+			_:a <dgraph.xid> "XID00001" .
+		`),
+	})
+
+	require.NoError(t, txn.Discard(ctx))
+	require.Error(t, err)
+	require.Contains(t, strings.ToLower(err.Error()), "no mutations allowed")
+}
+
+func mutateExistingAllowed1(t *testing.T, dg *dgo.Dgraph) {
+	ctx := context.Background()
+
+	txn := dg.NewTxn()
+	_, err := txn.Mutate(ctx, &api.Mutation{
+		SetNquads: []byte(`
+			_:a <name> "Alice" .
+		`),
+	})
+
+	require.NoError(t, txn.Commit(ctx))
+	require.NoError(t, err)
+}
+
+func mutateExistingAllowed2(t *testing.T, dg *dgo.Dgraph) {
+	ctx := context.Background()
+
+	txn := dg.NewTxn()
+	_, err := txn.Mutate(ctx, &api.Mutation{
+		SetNquads: []byte(`
+			_:s <size> "small" .
+		`),
+	})
+
+	require.NoError(t, txn.Commit(ctx))
+	require.NoError(t, err)
+}
+
+func TestMutationsDisallow(t *testing.T) {
+	conn, err := grpc.Dial(disallowModeAlpha, grpc.WithInsecure())
+	x.Check(err)
+	defer conn.Close()
+
+	t.Run("disallow drop all in no mutations mode",
+		runOn(conn, dropAllDisallowed))
+	t.Run("disallow mutate new predicate in no mutations mode",
+		runOn(conn, mutateNewDisallowed))
+	t.Run("disallow add predicate in no mutations mode",
+		runOn(conn, addPredicateDisallowed))
+	t.Run("disallow mutate existing predicate in no mutations mode",
+		runOn(conn, mutateExistingDisallowed))
+}
+
+func TestMutationsStrict(t *testing.T) {
+	conn1, err := grpc.Dial(strictModeAlphaGroup1, grpc.WithInsecure())
+	x.Check(err)
+	defer conn1.Close()
+
+	conn2, err := grpc.Dial(strictModeAlphaGroup2, grpc.WithInsecure())
+	x.Check(err)
+	defer conn2.Close()
+
+	t.Run("allow group1 drop all in strict mutations mode",
+		runOn(conn1, dropAllAllowed))
+	t.Run("allow group2 drop all in strict mutations mode",
+		runOn(conn2, dropAllAllowed))
+	t.Run("disallow group1 mutate new predicate in strict mutations mode",
+		runOn(conn1, mutateNewDisallowed2))
+	t.Run("disallow group2 mutate new predicate in strict mutations mode",
+		runOn(conn2, mutateNewDisallowed2))
+	t.Run("allow group1 add predicate in strict mutations mode",
+		runOn(conn1, addPredicateAllowed1))
+	t.Run("allow group2 add predicate in strict mutations mode",
+		runOn(conn2, addPredicateAllowed2))
+	t.Run("allow group1 mutate group1 predicate in strict mutations mode",
+		runOn(conn1, mutateExistingAllowed1))
+	t.Run("allow group2 mutate group1 predicate in strict mutations mode",
+		runOn(conn2, mutateExistingAllowed1))
+	t.Run("allow group1 mutate group2 predicate in strict mutations mode",
+		runOn(conn1, mutateExistingAllowed2))
+	t.Run("allow group2 mutate group2 predicate in strict mutations mode",
+		runOn(conn2, mutateExistingAllowed2))
+}