add /admin/schema endpoint (#4777)

Adds a POST `/admin/schema` endpoint which allows updating the GraphQL schema similar to how `/alter` works.

dgraph/cmd/alpha/http.go

@@ -21,6 +21,8 @@ import (
 	"compress/gzip"
 	"context"
 	"encoding/json"
+	"github.com/dgraph-io/dgraph/graphql/schema"
+	"github.com/dgraph-io/dgraph/graphql/web"
 	"io"
 	"io/ioutil"
 	"net/http"
@@ -143,20 +145,6 @@ func parseDuration(r *http.Request, name string) (time.Duration, error) {
 	return durationValue, nil
 }
 
-// Write response body, transparently compressing if necessary.
-func writeResponse(w http.ResponseWriter, r *http.Request, b []byte) (int, error) {
-	var out io.Writer = w
-
-	if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
-		w.Header().Set("Content-Encoding", "gzip")
-		gzw := gzip.NewWriter(w)
-		defer gzw.Close()
-		out = gzw
-	}
-
-	return out.Write(b)
-}
-
 // This method should just build the request and proxy it to the Query method of dgraph.Server.
 // It can then encode the response as appropriate before sending it back to the user.
 func queryHandler(w http.ResponseWriter, r *http.Request) {
@@ -277,7 +265,7 @@ func queryHandler(w http.ResponseWriter, r *http.Request) {
 	writeEntry("extensions", js)
 	x.Check2(out.WriteRune('}'))
 
-	if _, err := writeResponse(w, r, out.Bytes()); err != nil {
+	if _, err := x.WriteResponse(w, r, out.Bytes()); err != nil {
 		// If client crashes before server could write response, writeResponse will error out,
 		// Check2 will fatal and shut the server down in such scenario. We don't want that.
 		glog.Errorln("Unable to write response: ", err)
@@ -432,7 +420,7 @@ func mutationHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	_, _ = writeResponse(w, r, js)
+	_, _ = x.WriteResponse(w, r, js)
 }
 
 func commitHandler(w http.ResponseWriter, r *http.Request) {
@@ -480,7 +468,7 @@ func commitHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	_, _ = writeResponse(w, r, js)
+	_, _ = x.WriteResponse(w, r, js)
 }
 
 func handleAbort(startTs uint64) (map[string]interface{}, error) {
@@ -579,6 +567,50 @@ func alterHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	writeSuccessResponse(w, r)
+}
+
+func adminSchemaHandler(w http.ResponseWriter, r *http.Request, adminServer web.IServeGraphQL) {
+	if commonHandler(w, r) {
+		return
+	}
+
+	b := readRequest(w, r)
+	if b == nil {
+		return
+	}
+
+	md := metadata.New(nil)
+	ctx := metadata.NewIncomingContext(context.Background(), md)
+	ctx = x.AttachAccessJwt(ctx, r)
+
+	gqlReq := &schema.Request{}
+	gqlReq.Query = `
+		mutation updateGqlSchema($sch: String!) {
+			updateGQLSchema(input: {
+				set: {
+					schema: $sch
+				}
+			}) {
+				gqlSchema {
+					id
+				}
+			}
+		}`
+	gqlReq.Variables = map[string]interface{}{
+		"sch": string(b),
+	}
+
+	response := adminServer.Resolve(ctx, gqlReq)
+	if len(response.Errors) > 0 {
+		x.SetStatus(w, x.Error, response.Errors.Error())
+		return
+	}
+
+	writeSuccessResponse(w, r)
+}
+
+func writeSuccessResponse(w http.ResponseWriter, r *http.Request) {
 	res := map[string]interface{}{}
 	data := map[string]interface{}{}
 	data["code"] = x.Success
@@ -591,7 +623,7 @@ func alterHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	_, _ = writeResponse(w, r, js)
+	_, _ = x.WriteResponse(w, r, js)
 }
 
 // skipJSONUnmarshal stores the raw bytes as is while JSON unmarshaling.

dgraph/cmd/alpha/login_ee.go

@@ -80,7 +80,7 @@ func loginHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if _, err := writeResponse(w, r, js); err != nil {
+	if _, err := x.WriteResponse(w, r, js); err != nil {
 		glog.Errorf("Error while writing response: %v", err)
 	}
 }

dgraph/cmd/alpha/run.go

@@ -463,6 +463,9 @@ func setupServer(closer *y.Closer) {
 		})
 	}
 	http.Handle("/admin", whitelist(adminServer.HTTPHandler()))
+	http.HandleFunc("/admin/schema", func(w http.ResponseWriter, r *http.Request) {
+		adminSchemaHandler(w, r, adminServer)
+	})
 
 	addr := fmt.Sprintf("%s:%d", laddr, httpPort())
 	glog.Infof("Bringing up GraphQL HTTP API at %s/graphql", addr)

graphql/e2e/common/admin.go

@@ -181,6 +181,82 @@ const (
         ]
     }
 }`
+
+	adminSchemaEndptTypes = `
+	type A {
+		b: String
+		c: Int
+		d: Float
+	}`
+	adminSchemaEndptSchema = `{
+    "schema": [
+        {
+            "predicate": "A.b",
+            "type": "string"
+        },
+        {
+            "predicate": "A.c",
+            "type": "int"
+        },
+        {
+            "predicate": "A.d",
+            "type": "float"
+        },
+        {
+            "predicate": "dgraph.graphql.schema",
+            "type": "string"
+        },
+        {
+            "predicate": "dgraph.type",
+            "type": "string",
+            "index": true,
+            "tokenizer": [
+                "exact"
+            ],
+            "list": true
+        }
+    ],
+    "types": [
+        {
+            "fields": [
+                {
+                    "name": "A.b"
+                },
+                {
+                    "name": "A.c"
+                },
+                {
+                    "name": "A.d"
+                }
+            ],
+            "name": "A"
+        },
+        {
+            "fields": [
+                {
+                    "name": "dgraph.graphql.schema"
+                }
+            ],
+            "name": "dgraph.graphql"
+        }
+    ]
+}`
+	adminSchemaEndptGQLSchema = `{
+    "__type": {
+        "name": "A",
+        "fields": [
+            {
+                "name": "b"
+            },
+            {
+                "name": "c"
+            },
+            {
+                "name": "d"
+            }
+        ]
+    }
+}`
 )
 
 func admin(t *testing.T) {
@@ -196,6 +272,7 @@ func admin(t *testing.T) {
 	schemaIsInInitialState(t, client)
 	addGQLSchema(t, client)
 	updateSchema(t, client)
+	updateSchemaThroughAdminSchemaEndpt(t, client)
 }
 
 func schemaIsInInitialState(t *testing.T, client *dgo.Dgraph) {
@@ -229,6 +306,18 @@ func updateSchema(t *testing.T, client *dgo.Dgraph) {
 	introspect(t, updatedGQLSchema)
 }
 
+func updateSchemaThroughAdminSchemaEndpt(t *testing.T, client *dgo.Dgraph) {
+	err := addSchemaThroughAdminSchemaEndpt(graphqlAdminTestAdminSchemaURL, adminSchemaEndptTypes)
+	require.NoError(t, err)
+
+	resp, err := client.NewReadOnlyTxn().Query(context.Background(), "schema {}")
+	require.NoError(t, err)
+
+	require.JSONEq(t, adminSchemaEndptSchema, string(resp.GetJson()))
+
+	introspect(t, adminSchemaEndptGQLSchema)
+}
+
 func introspect(t *testing.T, expected string) {
 	queryParams := &GraphQLParams{
 		Query: `query {

graphql/e2e/common/common.go

@@ -42,10 +42,11 @@ const (
 	graphqlAdminURL = "http://localhost:8180/admin"
 	alphagRPC       = "localhost:9180"
 
-	adminDgraphHealthURL     = "http://localhost:8280/health?all"
-	graphqlAdminTestURL      = "http://localhost:8280/graphql"
-	graphqlAdminTestAdminURL = "http://localhost:8280/admin"
-	alphaAdminTestgRPC       = "localhost:9280"
+	adminDgraphHealthURL           = "http://localhost:8280/health?all"
+	graphqlAdminTestURL            = "http://localhost:8280/graphql"
+	graphqlAdminTestAdminURL       = "http://localhost:8280/admin"
+	graphqlAdminTestAdminSchemaURL = "http://localhost:8280/admin/schema"
+	alphaAdminTestgRPC             = "localhost:9280"
 )
 
 // GraphQLParams is parameters for the constructing a GraphQL query - that's
@@ -681,3 +682,33 @@ func addSchema(url string, schema string) error {
 
 	return nil
 }
+
+func addSchemaThroughAdminSchemaEndpt(url string, schema string) error {
+	req, err := http.NewRequest(http.MethodPost, url, strings.NewReader(schema))
+	if err != nil {
+		return errors.Wrap(err, "error running GraphQL query")
+	}
+
+	resp, err := runGQLRequest(req)
+	if err != nil {
+		return errors.Wrap(err, "error running GraphQL query")
+	}
+
+	var addResult struct {
+		Data struct {
+			Code    string
+			Message string
+		}
+	}
+
+	err = json.Unmarshal(resp, &addResult)
+	if err != nil {
+		return errors.Wrap(err, "error trying to unmarshal GraphQL mutation result")
+	}
+
+	if addResult.Data.Code != "Success" && addResult.Data.Message != "Done" {
+		return errors.New("GraphQL schema mutation failed")
+	}
+
+	return nil
+}

graphql/web/http.go

@@ -43,6 +43,9 @@ type IServeGraphQL interface {
 
 	// HTTPHandler returns a http.Handler that serves GraphQL.
 	HTTPHandler() http.Handler
+
+	// Resolve processes a GQL Request using the correct resolver and returns a GQL Response
+	Resolve(ctx context.Context, gqlReq *schema.Request) *schema.Response
 }
 
 type graphqlHandler struct {
@@ -65,6 +68,10 @@ func (gh *graphqlHandler) ServeGQL(resolver *resolve.RequestResolver) {
 	gh.resolver = resolver
 }
 
+func (gh *graphqlHandler) Resolve(ctx context.Context, gqlReq *schema.Request) *schema.Response {
+	return gh.resolver.Resolve(ctx, gqlReq)
+}
+
 // write chooses between the http response writer and gzip writer
 // and sends the schema response using that.
 func write(w http.ResponseWriter, rr *schema.Response, acceptGzip bool) {
@@ -96,19 +103,18 @@ func (gh *graphqlHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		panic("graphqlHandler not initialised")
 	}
 
+	ctx = x.AttachAccessJwt(ctx, r)
+
 	var res *schema.Response
 	gqlReq, err := getRequest(ctx, r)
 
-	ctx = x.AttachAccessJwt(ctx, r)
-
 	if err != nil {
 		res = schema.ErrorResponse(err)
 	} else {
 		res = gh.resolver.Resolve(ctx, gqlReq)
 	}
 
 	write(w, res, strings.Contains(r.Header.Get("Accept-Encoding"), "gzip"))
-
 }
 
 func (gh *graphqlHandler) isValid() bool {

x/x.go

@@ -19,10 +19,12 @@ package x
 import (
 	"bufio"
 	"bytes"
+	builtinGzip "compress/gzip"
 	"context"
 	"crypto/tls"
 	"encoding/json"
 	"fmt"
+	"io"
 	"math"
 	"math/rand"
 	"net"
@@ -338,6 +340,20 @@ func AttachAccessJwt(ctx context.Context, r *http.Request) context.Context {
 	return ctx
 }
 
+// Write response body, transparently compressing if necessary.
+func WriteResponse(w http.ResponseWriter, r *http.Request, b []byte) (int, error) {
+	var out io.Writer = w
+
+	if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
+		w.Header().Set("Content-Encoding", "gzip")
+		gzw := builtinGzip.NewWriter(w)
+		defer gzw.Close()
+		out = gzw
+	}
+
+	return out.Write(b)
+}
+
 // Min returns the minimum of the two given numbers.
 func Min(a, b uint64) uint64 {
 	if a < b {