github.com/dgraph-io/dgraph@v1.2.8/graphql/admin/health.go (about) 1 /* 2 * Copyright 2019 Dgraph Labs, Inc. and Contributors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package admin 18 19 import ( 20 "context" 21 "fmt" 22 23 "github.com/dgraph-io/dgraph/gql" 24 "github.com/dgraph-io/dgraph/graphql/schema" 25 ) 26 27 const ( 28 errNoConnection healthStatus = "ErrNoConnection" 29 noGraphQLSchema healthStatus = "NoGraphQLSchema" 30 healthy healthStatus = "Healthy" 31 ) 32 33 type healthStatus string 34 35 type healthResolver struct { 36 status healthStatus 37 format string 38 } 39 40 var statusMessage = map[healthStatus]string{ 41 errNoConnection: "Unable to contact Dgraph", 42 noGraphQLSchema: "Dgraph connection established but there's no GraphQL schema.", 43 healthy: "Dgraph connection established and serving GraphQL schema.", 44 } 45 46 func (hr *healthResolver) Rewrite(q schema.Query) (*gql.GraphQuery, error) { 47 msg := "message" 48 status := "status" 49 50 for _, f := range q.SelectionSet() { 51 if f.Name() == "message" { 52 msg = f.ResponseName() 53 } 54 if f.Name() == "status" { 55 status = f.ResponseName() 56 } 57 } 58 59 hr.format = fmt.Sprintf(`{"%s":[{"%s":"%%s","%s":"%%s"}]}`, q.ResponseName(), msg, status) 60 return nil, nil 61 } 62 63 func (hr *healthResolver) Query(ctx context.Context, query *gql.GraphQuery) ([]byte, error) { 64 return []byte(fmt.Sprintf(hr.format, statusMessage[hr.status], string(hr.status))), nil 65 }