graphql: duplicate /health in GraphQL /admin

dgraph/cmd/alpha/http.go

@@ -208,7 +208,7 @@ func queryHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	ctx := context.WithValue(context.Background(), query.DebugKey, isDebugMode)
-	ctx = attachAccessJwt(ctx, r)
+	ctx = x.AttachAccessJwt(ctx, r)
 
 	if queryTimeout != 0 {
 		var cancel context.CancelFunc
@@ -397,7 +397,7 @@ func mutationHandler(w http.ResponseWriter, r *http.Request) {
 	req.StartTs = startTs
 	req.CommitNow = commitNow
 
-	ctx := attachAccessJwt(context.Background(), r)
+	ctx := x.AttachAccessJwt(context.Background(), r)
 	resp, err := (&edgraph.Server{}).Query(ctx, req)
 	if err != nil {
 		x.SetStatusWithData(w, x.ErrorInvalidRequest, err.Error())
@@ -548,19 +548,6 @@ func handleCommit(startTs uint64, reqText []byte) (map[string]interface{}, error
 	return response, nil
 }
 
-func attachAccessJwt(ctx context.Context, r *http.Request) context.Context {
-	if accessJwt := r.Header.Get("X-Dgraph-AccessToken"); accessJwt != "" {
-		md, ok := metadata.FromIncomingContext(ctx)
-		if !ok {
-			md = metadata.New(nil)
-		}
-
-		md.Append("accessJwt", accessJwt)
-		ctx = metadata.NewIncomingContext(ctx, md)
-	}
-	return ctx
-}
-
 func alterHandler(w http.ResponseWriter, r *http.Request) {
 	if commonHandler(w, r) {
 		return
@@ -586,7 +573,7 @@ func alterHandler(w http.ResponseWriter, r *http.Request) {
 	// Pass in an auth token, if present.
 	md.Append("auth-token", r.Header.Get("X-Dgraph-AuthToken"))
 	ctx := metadata.NewIncomingContext(context.Background(), md)
-	ctx = attachAccessJwt(ctx, r)
+	ctx = x.AttachAccessJwt(ctx, r)
 	if _, err := (&edgraph.Server{}).Alter(ctx, op); err != nil {
 		x.SetStatus(w, x.Error, err.Error())
 		return

dgraph/cmd/alpha/run.go

@@ -289,7 +289,7 @@ func healthCheck(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
 		w.WriteHeader(http.StatusOK)
 
-		ctx := attachAccessJwt(context.Background(), r)
+		ctx := x.AttachAccessJwt(context.Background(), r)
 		var resp *api.Response
 		if resp, err = (&edgraph.Server{}).Health(ctx, true); err != nil {
 			x.SetStatus(w, x.Error, err.Error())
@@ -335,7 +335,7 @@ func stateHandler(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "application/json")
 
 	ctx := context.Background()
-	ctx = attachAccessJwt(ctx, r)
+	ctx = x.AttachAccessJwt(ctx, r)
 
 	var aResp *api.Response
 	if aResp, err = (&edgraph.Server{}).State(ctx); err != nil {

graphql/admin/admin.go

@@ -47,31 +47,26 @@ const (
 		"(Please let us know : https://github.com/dgraph-io/dgraph/issues)"
 
 	// GraphQL schema for /admin endpoint.
-	//
-	// Eventually we should generate this from just the types definition.
-	// But for now, that would add too much into the schema, so this is
-	// hand crafted to be one of our schemas so we can pass it into the
-	// pipeline.
 	graphqlAdminSchema = `
 	type GQLSchema @dgraph(type: "dgraph.graphql") {
 		id: ID!
 		schema: String!  @dgraph(type: "dgraph.graphql.schema")
 		generatedSchema: String!
 	}
-
-	type Health {
-		message: String!
-		status: HealthStatus!
-	}
-
-	enum HealthStatus {
-		ErrNoConnection
-		NoGraphQLSchema
-		Healthy
+
+	"""Node state is the state of an individual node int he Dgraph cluster """
+	type NodeState {
+		"""node type : either 'alpha' or 'zero'"""
+		instance: String
+		address: String
+		"""node health status : either 'healthy' or 'unhealthy'"""
+		status: String
+		group: Int
+		version: String
+		uptime: Int
+		lastEcho: Int
 	}
 
-	scalar DateTime
-
 	directive @dgraph(type: String, pred: String) on OBJECT | INTERFACE | FIELD_DEFINITION
 
 	type UpdateGQLSchemaPayload {
@@ -134,7 +129,7 @@ const (
 
 	type Query {
 		getGQLSchema: GQLSchema
-		health: Health
+		health: [NodeState]
 	}
 
 	type Mutation {
@@ -157,7 +152,6 @@ type gqlSchema struct {
 type adminServer struct {
 	rf       resolve.ResolverFactory
 	resolver *resolve.RequestResolver
-	status   healthStatus
 
 	// The mutex that locks schema update operations
 	mux sync.Mutex
@@ -213,7 +207,6 @@ func newAdminResolver(
 	server := &adminServer{
 		rf:                rf,
 		resolver:          resolve.New(adminSchema, rf),
-		status:            errNoConnection,
 		gqlServer:         gqlServer,
 		fns:               fns,
 		withIntrospection: withIntrospection,
@@ -275,7 +268,6 @@ func newAdminResolver(
 		defer server.mux.Unlock()
 
 		server.schema = newSchema
-		server.status = healthy
 		server.resetSchema(gqlSchema)
 	}, 1, closer)
 
@@ -288,14 +280,12 @@ func newAdminResolverFactory() resolve.ResolverFactory {
 	rf := resolverFactoryWithErrorMsg(errResolverNotFound).
 		WithQueryResolver("health",
 			func(q schema.Query) resolve.QueryResolver {
-				health := &healthResolver{
-					status: errNoConnection,
-				}
+				health := &healthResolver{}
 
 				return resolve.NewQueryResolver(
 					health,
 					health,
-					resolve.StdQueryCompletion())
+					resolve.AliasQueryCompletion())
 			}).
 		WithMutationResolver("updateGQLSchema", func(m schema.Mutation) resolve.MutationResolver {
 			return resolve.MutationResolverFunc(
@@ -370,26 +360,28 @@ func newAdminResolverFactory() resolve.ResolverFactory {
 }
 
 func (as *adminServer) initServer() {
-	var waitFor time.Duration
+	// It takes a few seconds for the Dgraph cluster to be up and running.
+	// Before that, trying to read the GraphQL schema will result in error:
+	// "Please retry again, server is not ready to accept requests."
+	// 5 seconds is a pretty reliable wait for a fresh instance to read the
+	// schema on a first try.
+	waitFor := 5 * time.Second
+
+	// Nothing else should be able to lock before here.  The admin resolvers aren't yet
+	// set up (they all just error), so we will obtain the lock here without contention.
+	// We then setup the admin resolvers and they must wait until we are done before the
+	// first admin calls will go through.
+	as.mux.Lock()
+	defer as.mux.Unlock()
+
+	as.addConnectedAdminResolvers()
 	for {
 		<-time.After(waitFor)
-		waitFor = 10 * time.Second
-
-		// Nothing else should be able to lock before here.  The admin resolvers aren't yet
-		// set up (they all just error), so we will obtain the lock here without contention.
-		// We then setup the admin resolvers and they must wait until we are done before the
-		// first admin calls will go through.
-		as.mux.Lock()
-		defer as.mux.Unlock()
-
-		as.addConnectedAdminResolvers()
-
-		as.status = noGraphQLSchema
 
 		sch, err := getCurrentGraphQLSchema(as.resolver)
 		if err != nil {
 			glog.Infof("Error reading GraphQL schema: %s.", err)
-			break
+			continue
 		} else if sch == nil {
 			glog.Infof("No GraphQL schema in Dgraph; serving empty GraphQL API")
 			break
@@ -411,7 +403,6 @@ func (as *adminServer) initServer() {
 		glog.Infof("Successfully loaded GraphQL schema.  Serving GraphQL API.")
 
 		as.schema = *sch
-		as.status = healthy
 		as.resetSchema(generatedSchema)
 
 		break
@@ -430,32 +421,21 @@ func (as *adminServer) addConnectedAdminResolvers() {
 	as.fns.Qe = qryExec
 	as.fns.Me = mutExec
 
-	as.rf.WithQueryResolver("health",
-		func(q schema.Query) resolve.QueryResolver {
-			health := &healthResolver{
-				status: as.status,
+	as.rf.WithMutationResolver("updateGQLSchema",
+		func(m schema.Mutation) resolve.MutationResolver {
+			updResolver := &updateSchemaResolver{
+				admin:                as,
+				baseAddRewriter:      addRw,
+				baseMutationRewriter: updRw,
+				baseMutationExecutor: mutExec,
 			}
 
-			return resolve.NewQueryResolver(
-				health,
-				health,
-				resolve.StdQueryCompletion())
+			return resolve.NewMutationResolver(
+				updResolver,
+				updResolver,
+				updResolver,
+				resolve.StdMutationCompletion(m.Name()))
 		}).
-		WithMutationResolver("updateGQLSchema",
-			func(m schema.Mutation) resolve.MutationResolver {
-				updResolver := &updateSchemaResolver{
-					admin:                as,
-					baseAddRewriter:      addRw,
-					baseMutationRewriter: updRw,
-					baseMutationExecutor: mutExec,
-				}
-
-				return resolve.NewMutationResolver(
-					updResolver,
-					updResolver,
-					updResolver,
-					resolve.StdMutationCompletion(m.Name()))
-			}).
 		WithQueryResolver("getGQLSchema",
 			func(q schema.Query) resolve.QueryResolver {
 				getResolver := &getSchemaResolver{
@@ -512,8 +492,6 @@ func (as *adminServer) resetSchema(gqlSchema schema.Schema) {
 	}
 
 	as.gqlServer.ServeGQL(resolve.New(gqlSchema, resolverFactory))
-
-	as.status = healthy
 }
 
 func writeResponse(m schema.Mutation, code, message string) []byte {

graphql/admin/health.go

@@ -17,49 +17,40 @@
 package admin
 
 import (
+	"bytes"
 	"context"
-	"fmt"
 
+	"github.com/dgraph-io/dgo/v2/protos/api"
+	"github.com/dgraph-io/dgraph/edgraph"
 	"github.com/dgraph-io/dgraph/gql"
 	"github.com/dgraph-io/dgraph/graphql/schema"
+	"github.com/dgraph-io/dgraph/x"
+	"github.com/pkg/errors"
 )
 
-const (
-	errNoConnection healthStatus = "ErrNoConnection"
-	noGraphQLSchema healthStatus = "NoGraphQLSchema"
-	healthy         healthStatus = "Healthy"
-)
-
-type healthStatus string
-
 type healthResolver struct {
-	status healthStatus
-	format string
 }
 
-var statusMessage = map[healthStatus]string{
-	errNoConnection: "Unable to contact Dgraph",
-	noGraphQLSchema: "Dgraph connection established but there's no GraphQL schema.",
-	healthy:         "Dgraph connection established and serving GraphQL schema.",
+func (hr *healthResolver) Rewrite(q schema.Query) (*gql.GraphQuery, error) {
+	return nil, nil
 }
 
-func (hr *healthResolver) Rewrite(q schema.Query) (*gql.GraphQuery, error) {
-	msg := "message"
-	status := "status"
+func (hr *healthResolver) Query(ctx context.Context, query *gql.GraphQuery) ([]byte, error) {
+	var err error
 
-	for _, f := range q.SelectionSet() {
-		if f.Name() == "message" {
-			msg = f.ResponseName()
-		}
-		if f.Name() == "status" {
-			status = f.ResponseName()
-		}
+	var resp *api.Response
+	var respErr error
+	if resp, respErr = (&edgraph.Server{}).Health(ctx, true); respErr != nil {
+		err = errors.Errorf("%s: %s", x.Error, respErr.Error())
+	}
+	if resp == nil {
+		err = errors.Errorf("%s: %s", x.ErrorNoData, "No state information available.")
 	}
 
-	hr.format = fmt.Sprintf(`{"%s":[{"%s":"%%s","%s":"%%s"}]}`, q.ResponseName(), msg, status)
-	return nil, nil
-}
+	var buf bytes.Buffer
+	x.Check2(buf.WriteString(`{ "health":`))
+	x.Check2(buf.Write(resp.Json))
+	x.Check2(buf.WriteString(`}`))
 
-func (hr *healthResolver) Query(ctx context.Context, query *gql.GraphQuery) ([]byte, error) {
-	return []byte(fmt.Sprintf(hr.format, statusMessage[hr.status], string(hr.status))), nil
+	return buf.Bytes(), err
 }