feat(graphql): adds @default directive to graphql (#8017) (#8837)

Co-authored-by: shivaji-dgraph <shivaji@dgraph.io>

graphql/e2e/schema/apollo_service_response.graphql

@@ -118,6 +118,10 @@ input CustomHTTP {
 	skipIntrospection: Boolean
 }
 
+input DgraphDefault {
+	value: String
+}
+
 type Point {
 	longitude: Float!
 	latitude: Float!
@@ -201,6 +205,7 @@ directive @search(by: [String!]) on FIELD_DEFINITION
 directive @embedding on FIELD_DEFINITION
 directive @dgraph(type: String, pred: String) on OBJECT | INTERFACE | FIELD_DEFINITION
 directive @id(interface: Boolean) on FIELD_DEFINITION
+directive @default(add: DgraphDefault, update: DgraphDefault) on FIELD_DEFINITION
 directive @withSubscription on OBJECT | INTERFACE | FIELD_DEFINITION
 directive @secret(field: String!, pred: String) on OBJECT | INTERFACE
 directive @remote on OBJECT | INTERFACE | UNION | INPUT_OBJECT | ENUM

graphql/e2e/schema/generatedSchema.graphql

@@ -99,6 +99,10 @@ input CustomHTTP {
 	skipIntrospection: Boolean
 }
 
+input DgraphDefault {
+	value: String
+}
+
 type Point {
 	longitude: Float!
 	latitude: Float!
@@ -182,6 +186,7 @@ directive @search(by: [String!]) on FIELD_DEFINITION
 directive @embedding on FIELD_DEFINITION
 directive @dgraph(type: String, pred: String) on OBJECT | INTERFACE | FIELD_DEFINITION
 directive @id(interface: Boolean) on FIELD_DEFINITION
+directive @default(add: DgraphDefault, update: DgraphDefault) on FIELD_DEFINITION
 directive @withSubscription on OBJECT | INTERFACE | FIELD_DEFINITION
 directive @secret(field: String!, pred: String) on OBJECT | INTERFACE
 directive @auth(

graphql/resolve/add_mutation_test.yaml

@@ -5499,4 +5499,163 @@
   error2:
     {
       "message": "failed to rewrite mutation payload because field id cannot be empty"
-    }
+    }
+
+-
+  name: "Add mutation with @default directive"
+  gqlmutation: |
+    mutation($input: [AddBookingInput!]!) {
+      addBooking(input: $input) {
+        booking {
+          name
+          created
+          updated
+        }
+      }
+    }
+  gqlvariables: |
+    {
+      "input": [
+        {
+          "name": "Holiday to Bermuda"
+        }
+      ]
+    }
+  explanation: "As booking has @default fields and is being added, these should be set to the default add value"
+  dgmutations:
+    - setjson: |
+        {
+            "Booking.created": "2000-01-01T00:00:00.00Z",
+            "Booking.active": "false",
+            "Booking.count": "1",
+            "Booking.hotel": "add",
+            "Booking.length": "1.1",
+            "Booking.status": "ACTIVE",
+            "Booking.name": "Holiday to Bermuda",
+            "Booking.updated": "2000-01-01T00:00:00.00Z",
+            "dgraph.type": [
+                    "Booking"
+                ],
+            "uid":"_:Booking_1"
+        }
+
+-
+  name: "Add mutation with @default directive uses provided values"
+  gqlmutation: |
+    mutation($input: [AddBookingInput!]!) {
+      addBooking(input: $input) {
+        booking {
+          name
+          created
+          updated
+        }
+      }
+    }
+  gqlvariables: |
+    {
+      "input": [
+        {
+          "name": "Holiday to Bermuda",
+          "created": "2022-10-12T07:20:50.52Z",
+          "updated": "2023-10-12T07:20:50.52Z",
+          "active": false,
+          "length": 12.3,
+          "status": "INACTIVE",
+          "hotel": "provided"
+        }
+      ]
+    }
+  explanation: "Fields with @default(add) should use input values if provided (note that count is still using default)"
+  dgmutations:
+    - setjson: |
+        {
+            "Booking.name": "Holiday to Bermuda",
+            "Booking.created": "2022-10-12T07:20:50.52Z",
+            "Booking.updated": "2023-10-12T07:20:50.52Z",
+            "Booking.active": false,
+            "Booking.count": "1",
+            "Booking.hotel": "provided",
+            "Booking.length": 12.3,
+            "Booking.status": "INACTIVE",
+            "dgraph.type": [
+                    "Booking"
+                ],
+            "uid":"_:Booking_1"
+        }
+
+-
+  name: "Upsert mutation with @default directives where only one of the nodes exists"
+  explanation: "Booking1 should only have updated timestamp as it exists, Booking2 should have created and updated timestamps"
+  gqlmutation: |
+    mutation addBookingXID($input: [AddBookingXIDInput!]!) {
+      addBookingXID(input: $input, upsert: true) {
+        bookingXID {
+          name
+        }
+      }
+    }
+  gqlvariables: |
+    { "input":
+      [
+        {
+          "id": "Booking1",
+          "name": "Trip to Bermuda"
+        },
+        {
+          "id": "Booking2",
+          "name": "Trip to Antigua"
+        }
+      ]
+    }
+  dgquery: |-
+    query {
+      BookingXID_1(func: eq(BookingXID.id, "Booking1")) {
+        uid
+        dgraph.type
+      }
+      BookingXID_2(func: eq(BookingXID.id, "Booking2")) {
+        uid
+        dgraph.type
+      }
+    }
+  qnametouid: |-
+    {
+      "BookingXID_1": "0x11"
+    }
+  dgquerysec: |-
+    query {
+      BookingXID_1 as BookingXID_1(func: uid(0x11)) @filter(type(BookingXID)) {
+        uid
+      }
+    }
+  dgmutations:
+    - setjson: |
+        {
+          "uid" : "uid(BookingXID_1)",
+          "BookingXID.id": "Booking1",
+          "BookingXID.name": "Trip to Bermuda",
+          "BookingXID.updated": "2000-01-01T00:00:00.00Z",
+          "BookingXID.active": "true",
+          "BookingXID.count": "2",
+          "BookingXID.length": "1.2",
+          "BookingXID.status": "INACTIVE",
+          "BookingXID.hotel": "update"
+        }
+      cond: "@if(gt(len(BookingXID_1), 0))"
+    - setjson: |
+        {
+          "uid": "_:BookingXID_2",
+          "BookingXID.id": "Booking2",
+          "BookingXID.name": "Trip to Antigua",
+          "BookingXID.created": "2000-01-01T00:00:00.00Z",
+          "BookingXID.updated": "2000-01-01T00:00:00.00Z",
+          "BookingXID.active": "false",
+          "BookingXID.count": "1",
+          "BookingXID.length": "1.1",
+          "BookingXID.status": "ACTIVE",
+          "BookingXID.hotel": "add",
+          "dgraph.type": [
+            "BookingXID"
+          ]
+        }
+

graphql/resolve/mutation_rewriter.go

@@ -34,9 +34,11 @@ import (
 )
 
 const (
-	MutationQueryVar        = "x"
-	MutationQueryVarUID     = "uid(x)"
-	updateMutationCondition = `gt(len(x), 0)`
+	MutationQueryVar          = "x"
+	MutationQueryVarUID       = "uid(x)"
+	updateMutationCondition   = `gt(len(x), 0)`
+	defaultDirectiveUpdateAct = "update"
+	defaultDirectiveAddAct    = "add"
 )
 
 // Enum passed on to rewriteObject function.
@@ -1587,6 +1589,8 @@ func rewriteObject(
 		}
 	}
 
+	action := defaultDirectiveUpdateAct
+
 	// This is not an XID reference. This is also not a UID reference.
 	// This is definitely a new node.
 	// Create new node
@@ -1635,6 +1639,19 @@ func rewriteObject(
 		// "_:Project2" . myUID will store the variable generated to reference this node.
 		newObj["dgraph.type"] = dgraphTypes
 		newObj["uid"] = myUID
+		action = defaultDirectiveAddAct
+	}
+
+	// Now we know whether this is a new node or not, we can set @default(add/update) fields
+	for _, field := range typ.Fields() {
+		var pred = field.DgraphPredicate()
+		if newObj[pred] != nil {
+			continue
+		}
+		var value = field.GetDefaultValue(action)
+		if value != nil {
+			newObj[pred] = value
+		}
 	}
 
 	// Add Inverse Link if necessary

graphql/resolve/schema.graphql

@@ -175,6 +175,32 @@ type Student implements People {
     taughtBy: [Teacher] @hasInverse(field: "teaches")
 }
 
+# For testing default values
+type Booking {
+    id: ID!
+    name: String!
+    created: DateTime! @default(add: {value: "$now"})
+    updated: DateTime! @default(add: {value: "$now"}, update: {value: "$now"})
+    count: Int! @default(add: {value: "1"}, update: {value: "2"})
+    length: Float! @default(add: {value: "1.1"}, update: {value: "1.2"})
+    hotel: String! @default(add: {value: "add"}, update: {value: "update"})
+    active: Boolean! @default(add: {value: "false"}, update: {value: "true"})
+    status: Status! @default(add: {value: "ACTIVE"}, update: {value: "INACTIVE"})
+}
+
+# For testing default values with upserts
+type BookingXID {
+    id: String! @id
+    name: String!
+    created: DateTime! @default(add: {value: "$now"})
+    updated: DateTime! @default(add: {value: "$now"}, update: {value: "$now"})
+    count: Int! @default(add: {value: "1"}, update: {value: "2"})
+    length: Float! @default(add: {value: "1.1"}, update: {value: "1.2"})
+    hotel: String! @default(add: {value: "add"}, update: {value: "update"})
+    active: Boolean! @default(add: {value: "false"}, update: {value: "true"})
+    status: Status! @default(add: {value: "ACTIVE"}, update: {value: "INACTIVE"})
+}
+
 type Comment {
     id: ID!
     author: String!

graphql/resolve/update_mutation_test.yaml

@@ -2331,7 +2331,7 @@
   explaination: "If nested object have inherited @id field which have interface argument set, and that
    field already exist in some other implementing type than we returns error.In below mutation manages
   is of type LibraryMember but node with given refID already exist in some other
-   type than LibraryMember"
+   type than than LibraryMember"
   gqlmutation: |
     mutation update($patch: UpdateLibraryManagerInput!) {
       updateLibraryManager(input: $patch) {
@@ -2447,3 +2447,88 @@
          "uid": "uid(x)"
        }
     cond: "@if(gt(len(x), 0))"
+
+-
+  name: "Update with @default directive"
+  gqlmutation: |
+    mutation updateBooking($patch: UpdateBookingInput!) {
+      updateBooking(input: $patch) {
+        booking {
+          id
+        }
+      }
+    }
+  gqlvariables: |
+    { "patch":
+      { "filter": {
+          "id": ["0x123", "0x124"]
+        },
+        "set": {
+          "name": "Flight to Antigua"
+        }
+      }
+    }
+  explanation: "The update patch should include default values on the fields with the @default(update:) directive"
+  dgquerysec: |-
+    query {
+      x as updateBooking(func: uid(0x123, 0x124)) @filter(type(Booking)) {
+        uid
+      }
+    }
+  dgmutations:
+    - setjson: |
+        { "uid" : "uid(x)",
+          "Booking.name": "Flight to Antigua",
+          "Booking.updated": "2000-01-01T00:00:00.00Z",
+          "Booking.active": "true",
+          "Booking.count": "2",
+          "Booking.length": "1.2",
+          "Booking.status": "INACTIVE",
+          "Booking.hotel": "update"
+        }
+      cond: "@if(gt(len(x), 0))"
+
+-
+  name: "Update with @default directive uses provided values"
+  gqlmutation: |
+    mutation updateBooking($patch: UpdateBookingInput!) {
+      updateBooking(input: $patch) {
+        booking {
+          id
+        }
+      }
+    }
+  gqlvariables: |
+    { "patch":
+      { "filter": {
+          "id": ["0x123", "0x124"]
+        },
+        "set": {
+          "name": "Flight to Antigua",
+          "updated": "2022-10-12T07:20:50.52Z",
+          "active": false,
+          "length": 12.3,
+          "status": "ACTIVE",
+          "hotel": "provided"
+        }
+      }
+    }
+  explanation: "Fields with @default(update) should use input values if provided (note that count is still using default)"
+  dgquerysec: |-
+    query {
+      x as updateBooking(func: uid(0x123, 0x124)) @filter(type(Booking)) {
+        uid
+      }
+    }
+  dgmutations:
+    - setjson: |
+        { "uid" : "uid(x)",
+          "Booking.name": "Flight to Antigua",
+          "Booking.updated": "2022-10-12T07:20:50.52Z",
+          "Booking.active": false,
+          "Booking.count": "2",
+          "Booking.length": 12.3,
+          "Booking.status": "ACTIVE",
+          "Booking.hotel": "provided"
+        }
+      cond: "@if(gt(len(x), 0))"