Add asynchronous task API (#7781)

* Revert dd183aa
* Revert 4418a7a
* Cherry pick cfdf7a5
* Cherry pick 60bec16
* Cherry pick 9e1337b
* Cherry pick 6b188f2

(cherry picked from commit 7e2e860)

Author: ajeetdsouza

dgraph/cmd/alpha/admin.go

@@ -83,8 +83,6 @@ func getAdminMux() *http.ServeMux {
 		http.MethodPut:  true,
 		http.MethodPost: true,
 	}, adminAuthHandler(http.HandlerFunc(drainingHandler))))
-	adminMux.Handle("/admin/export", allowedMethodsHandler(allowedMethods{http.MethodGet: true},
-		adminAuthHandler(http.HandlerFunc(exportHandler))))
 	adminMux.Handle("/admin/config/cache_mb", allowedMethodsHandler(allowedMethods{
 		http.MethodGet: true,
 		http.MethodPut: true,
@@ -160,46 +158,6 @@ func shutDownHandler(w http.ResponseWriter, r *http.Request) {
 	x.Check2(w.Write([]byte(`{"code": "Success", "message": "Server is shutting down"}`)))
 }
 
-func exportHandler(w http.ResponseWriter, r *http.Request) {
-	if err := r.ParseForm(); err != nil {
-		x.SetHttpStatus(w, http.StatusBadRequest, "Parse of export request failed.")
-		return
-	}
-
-	format := worker.DefaultExportFormat
-	if vals, ok := r.Form["format"]; ok {
-		if len(vals) > 1 {
-			x.SetHttpStatus(w, http.StatusBadRequest,
-				"Only one export format may be specified.")
-			return
-		}
-		format = worker.NormalizeExportFormat(vals[0])
-		if format == "" {
-			x.SetHttpStatus(w, http.StatusBadRequest, "Invalid export format.")
-			return
-		}
-	}
-
-	gqlReq := &schema.Request{
-		Query: `
-		mutation export($format: String) {
-		  export(input: {format: $format}) {
-			response {
-			  code
-			}
-		  }
-		}`,
-		Variables: map[string]interface{}{},
-	}
-
-	if resp := resolveWithAdminServer(gqlReq, r, adminServer); len(resp.Errors) != 0 {
-		x.SetStatus(w, resp.Errors[0].Message, "Export failed.")
-		return
-	}
-	w.Header().Set("Content-Type", "application/json")
-	x.Check2(w.Write([]byte(`{"code": "Success", "message": "Export completed."}`)))
-}
-
 func memoryLimitHandler(w http.ResponseWriter, r *http.Request) {
 	switch r.Method {
 	case http.MethodGet:

dgraph/cmd/alpha/admin_backup.go

@@ -755,6 +755,7 @@ func run() {
 	glog.Infof("worker.Config: %+v", worker.Config)
 
 	worker.InitServerState()
+	worker.InitTasks()
 
 	if Alpha.Conf.GetBool("expose_trace") {
 		// TODO: Remove this once we get rid of event logs.

dgraph/cmd/alpha/run.go

@@ -57,10 +57,10 @@ type shardState struct {
 
 func newMapperBuffer(opt *options) *z.Buffer {
 	sz := float64(opt.MapBufSize) * 1.1
-	buf, err := z.NewBufferWithDir(int(sz), 2*int(opt.MapBufSize), z.UseMmap,
-		filepath.Join(opt.TmpDir, bufferDir), "Mapper.Buffer")
+	tmpDir := filepath.Join(opt.TmpDir, bufferDir)
+	buf, err := z.NewBufferTmp(tmpDir, int(sz))
 	x.Check(err)
-	return buf
+	return buf.WithMaxSize(2 * int(opt.MapBufSize))
 }
 
 func newMapper(st *state) *mapper {

dgraph/cmd/bulk/mapper.go

@@ -434,11 +434,9 @@ func bufferStats(cbuf *z.Buffer) {
 }
 
 func getBuf(dir string) *z.Buffer {
-	cbuf, err := z.NewBufferWithDir(64<<20, 64<<30, z.UseCalloc,
-		filepath.Join(dir, bufferDir), "Reducer.GetBuf")
-	x.Check(err)
-	cbuf.AutoMmapAfter(1 << 30)
-	return cbuf
+	return z.NewBuffer(64<<20, "Reducer.GetBuf").
+		WithAutoMmap(1<<30, filepath.Join(dir, bufferDir)).
+		WithMaxSize(64 << 30)
 }
 
 func (r *reducer) reduce(partitionKeys [][]byte, mapItrs []*mapIterator, ci *countIndexer) {

dgraph/cmd/bulk/reduce.go

@@ -59,15 +59,16 @@ func (o *Oracle) Init() {
 	o.commits = make(map[uint64]uint64)
 	// Remove the older btree file, before creating NewTree, as it may contain stale data leading
 	// to wrong results.
-	o.keyCommit = z.NewTree()
+	o.keyCommit = z.NewTree("oracle")
 	o.subscribers = make(map[int]chan pb.OracleDelta)
 	o.updates = make(chan *pb.OracleDelta, 100000) // Keeping 1 second worth of updates.
 	o.doneUntil.Init(nil)
 	go o.sendDeltasToSubscribers()
 }
 
-// oracle close releases the memory associated with btree used for keycommit.
+// close releases the memory associated with btree used for keycommit.
 func (o *Oracle) close() {
+	o.keyCommit.Close()
 }
 
 func (o *Oracle) updateStartTxnTs(ts uint64) {

dgraph/cmd/zero/oracle.go

@@ -127,7 +127,7 @@ instances to achieve high-availability.
 		Head("Audit options").
 		Flag("output",
 			`[stdout, /path/to/dir] This specifies where audit logs should be output to.
-			"stdout" is for standard output. You can also specify the directory where audit logs 
+			"stdout" is for standard output. You can also specify the directory where audit logs
 			will be saved. When stdout is specified as output other fields will be ignored.`).
 		Flag("compress",
 			"Enables the compression of old audit logs.").

dgraph/cmd/zero/run.go

@@ -19,7 +19,7 @@ require (
 	github.com/dgraph-io/gqlgen v0.13.2
 	github.com/dgraph-io/gqlparser/v2 v2.2.0
 	github.com/dgraph-io/graphql-transport-ws v0.0.0-20210223074046-e5b8b80bb4ed
-	github.com/dgraph-io/ristretto v0.0.4-0.20210310100713-a4346e5d1f90
+	github.com/dgraph-io/ristretto v0.0.4-0.20210504190834-0bf2acd73aa3
 	github.com/dgraph-io/simdjson-go v0.3.0
 	github.com/dgrijalva/jwt-go v3.2.0+incompatible
 	github.com/dgrijalva/jwt-go/v4 v4.0.0-preview1

go.mod

@@ -89,6 +89,8 @@ github.com/cenkalti/backoff v2.1.1+incompatible/go.mod h1:90ReRw6GdpyfrHakVjL/QH
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/cespare/xxhash v1.1.0 h1:a6HrQnmkObjyL+Gs60czilIUGqrzKutQD6XZog3p+ko=
 github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=
+github.com/cespare/xxhash/v2 v2.1.1 h1:6MnRN8NT7+YBpUIWxHtefFZOKTAPgGjpQSxqLNn0+qY=
+github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
 github.com/codahale/hdrhistogram v0.0.0-20161010025455-3a0bb77429bd h1:qMd81Ts1T2OTKmB4acZcyKaMtRnY5Y44NuXGX2GFJ1w=
 github.com/codahale/hdrhistogram v0.0.0-20161010025455-3a0bb77429bd/go.mod h1:sE/e/2PUdi/liOCUjSTXgM1o87ZssimdTWN964YiIeI=
@@ -129,8 +131,8 @@ github.com/dgraph-io/gqlparser/v2 v2.2.0/go.mod h1:MYS4jppjyx8b9tuUtjV7jU1UFZK6P
 github.com/dgraph-io/graphql-transport-ws v0.0.0-20210223074046-e5b8b80bb4ed h1:pgGMBoTtFhR+xkyzINaToLYRurHn+6pxMYffIGmmEPc=
 github.com/dgraph-io/graphql-transport-ws v0.0.0-20210223074046-e5b8b80bb4ed/go.mod h1:7z3c/5w0sMYYZF5bHsrh8IH4fKwG5O5Y70cPH1ZLLRQ=
 github.com/dgraph-io/ristretto v0.0.4-0.20210309073149-3836124cdc5a/go.mod h1:MIonLggsKgZLUSt414ExgwNtlOL5MuEoAJP514mwGe8=
-github.com/dgraph-io/ristretto v0.0.4-0.20210310100713-a4346e5d1f90 h1:arWVlUO9NhZ/2vWprIqpe825GISUPpgJhU/b0ep3j/M=
-github.com/dgraph-io/ristretto v0.0.4-0.20210310100713-a4346e5d1f90/go.mod h1:MIonLggsKgZLUSt414ExgwNtlOL5MuEoAJP514mwGe8=
+github.com/dgraph-io/ristretto v0.0.4-0.20210504190834-0bf2acd73aa3 h1:jU/wpYsEL+8JPLf/QcjkQKI5g0dOjSuwcMjkThxt5x0=
+github.com/dgraph-io/ristretto v0.0.4-0.20210504190834-0bf2acd73aa3/go.mod h1:fux0lOrBhrVCJd3lcTHsIJhq1T2rokOu6v9Vcb3Q9ug=
 github.com/dgraph-io/simdjson-go v0.3.0 h1:h71LO7vR4LHMPUhuoGN8bqGm1VNfGOlAG8BI6iDUKw0=
 github.com/dgraph-io/simdjson-go v0.3.0/go.mod h1:Otpysdjaxj9OGaJusn4pgQV7OFh2bELuHANq0I78uvY=
 github.com/dgrijalva/jwt-go v3.2.0+incompatible h1:7qlOGliEKZXTDg6OTjfoBKDXWrumCAMpl/TFQ4/5kLM=

go.sum

@@ -55,9 +55,9 @@ const (
     """
 	The UInt64 scalar type represents an unsigned 64‐bit numeric non‐fractional value.
 	UInt64 can represent values in range [0,(2^64 - 1)].
-	""" 
+	"""
     scalar UInt64
-	
+
 	"""
 	The DateTime scalar type represents date and time as a string in RFC3339 format.
 	For example: "1985-04-12T23:20:50.52Z" represents 20 minutes and 50.52 seconds after the 23rd hour of April 12th, 1985 in UTC.
@@ -243,14 +243,19 @@ const (
 		anonymous: Boolean
 	}
 
+	input TaskInput {
+		id: String!
+	}
+
 	type Response {
 		code: String
 		message: String
 	}
 
 	type ExportPayload {
-		response: Response
 		exportedFiles: [String]
+		response: Response
+		taskId: String
 	}
 
 	type DrainingPayload {
@@ -261,6 +266,26 @@ const (
 		response: Response
 	}
 
+	type TaskPayload {
+		kind: TaskKind
+		status: TaskStatus
+		lastUpdated: DateTime
+	}
+
+	enum TaskStatus {
+		Queued
+		Running
+		Failed
+		Success
+		Unknown
+	}
+
+	enum TaskKind {
+		Backup
+		Export
+		Unknown
+	}
+
 	input ConfigInput {
 		"""
 		Estimated memory the caches can take. Actual usage by the process would be
@@ -367,6 +392,7 @@ const (
 		health: [NodeState]
 		state: MembershipState
 		config: Config
+		task(input: TaskInput!): TaskPayload
 		` + adminQueries + `
 	}
 
@@ -724,7 +750,6 @@ func newAdminResolver(
 }
 
 func newAdminResolverFactory() resolve.ResolverFactory {
-
 	adminMutationResolvers := map[string]resolve.MutationResolverFunc{
 		"addNamespace":      resolveAddNamespace,
 		"backup":            resolveBackup,
@@ -757,18 +782,21 @@ func newAdminResolverFactory() resolve.ResolverFactory {
 		WithQueryResolver("listBackups", func(q schema.Query) resolve.QueryResolver {
 			return resolve.QueryResolverFunc(resolveListBackups)
 		}).
-		WithMutationResolver("updateGQLSchema", func(m schema.Mutation) resolve.MutationResolver {
-			return resolve.MutationResolverFunc(
-				func(ctx context.Context, m schema.Mutation) (*resolve.Resolved, bool) {
-					return &resolve.Resolved{Err: errors.Errorf(errMsgServerNotReady), Field: m},
-						false
-				})
+		WithQueryResolver("task", func(q schema.Query) resolve.QueryResolver {
+			return resolve.QueryResolverFunc(resolveTask)
 		}).
 		WithQueryResolver("getGQLSchema", func(q schema.Query) resolve.QueryResolver {
 			return resolve.QueryResolverFunc(
 				func(ctx context.Context, query schema.Query) *resolve.Resolved {
 					return &resolve.Resolved{Err: errors.Errorf(errMsgServerNotReady), Field: q}
 				})
+		}).
+		WithMutationResolver("updateGQLSchema", func(m schema.Mutation) resolve.MutationResolver {
+			return resolve.MutationResolverFunc(
+				func(ctx context.Context, m schema.Mutation) (*resolve.Resolved, bool) {
+					return &resolve.Resolved{Err: errors.Errorf(errMsgServerNotReady), Field: m},
+						false
+				})
 		})
 	for gqlMut, resolver := range adminMutationResolvers {
 		// gotta force go to evaluate the right function at each loop iteration