Online restores only processes backups for the alpha's group (dgraph-…

…io#5588)

I changed the test backup to have three groups instead of one and I noticed that
the test didn't work anymore. There was a missing check that caused every
group's backup to be restored to the alpha. After introducing the check, all
tests pass again.

Fixes DGRAPH-1663

systest/online-restore/backup/dgraph.20200605.233745.571/manifest.json

@@ -0,0 +1 @@
+{"type":"full","since":15,"groups":{"1":["dgraph.type","dgraph.graphql.xid","dgraph.graphql.schema"],"2":[],"3":[]},"backup_id":"cranky_bartik8","backup_num":1,"encrypted":true}

systest/online-restore/backup/dgraph.20200605.233745.571/r15-g2.backup

@@ -0,0 +1 @@
+�DnjzEM)�ڟ��͈9�Dk\�~�"�P/�^�-2#63�\{NR�<I�@[ۇe�[vVw��p&1j��fGl{��hX7�@9�Fo�D��{��h�6|�F

systest/online-restore/backup/dgraph.20200605.233956.732/manifest.json

@@ -0,0 +1 @@
+{"type":"incremental","since":2106,"groups":{"1":["performance.actor","dgraph.graphql.xid","dgraph.graphql.schema","dgraph.type","rating","rated"],"2":["email","performance.film","performance.character","name"],"3":["country","loc","genre","initial_release_date","performance.character_note","starring","director.film","actor.film","tagline","cut.note"]},"backup_id":"cranky_bartik8","backup_num":2,"encrypted":true}

systest/online-restore/docker-compose.yml

@@ -1,4 +1,4 @@
-# Auto-generated with: [./compose -a 1 -z 1 --ratel -w]
+# Auto-generated with: [./compose --num_zeros 1 --num_alphas 3 --ratel]
 #
 version: "3.5"
 services:
@@ -23,10 +23,64 @@ services:
     - type: bind
       source: ./backup
       target: /data/backup
-      read_only: true
+      read_only: false
     command: /gobin/dgraph alpha -o 100 --my=alpha1:7180 --lru_mb=1024 --zero=zero1:5180
-      --logtostderr -v=2 --idx=1 --whitelist=10.0.0.0/8,172.16.0.0/12,192.168.0.0/16
-      --encryption_key_file /data/keys/enc_key
+      --logtostderr -v=2 --idx=1 --encryption_key_file /data/keys/enc_key
+      --whitelist=10.0.0.0/8,172.16.0.0/12,192.168.0.0/16
+  alpha2:
+    image: dgraph/dgraph:latest
+    container_name: alpha2
+    working_dir: /data/alpha2
+    depends_on:
+    - alpha1
+    labels:
+      cluster: test
+    ports:
+    - 8182:8182
+    - 9182:9182
+    volumes:
+    - type: bind
+      source: $GOPATH/bin
+      target: /gobin
+      read_only: true
+    - type: bind
+      source: ./keys
+      target: /data/keys
+      read_only: true
+    - type: bind
+      source: ./backup
+      target: /data/backup
+      read_only: false
+    command: /gobin/dgraph alpha -o 102 --my=alpha2:7182 --lru_mb=1024 --zero=zero1:5180
+      --logtostderr -v=2 --idx=2 --encryption_key_file /data/keys/enc_key
+      --whitelist=10.0.0.0/8,172.16.0.0/12,192.168.0.0/16
+  alpha3:
+    image: dgraph/dgraph:latest
+    container_name: alpha3
+    working_dir: /data/alpha3
+    depends_on:
+    - alpha2
+    labels:
+      cluster: test
+    ports:
+    - 8183:8183
+    - 9183:9183
+    volumes:
+    - type: bind
+      source: $GOPATH/bin
+      target: /gobin
+      read_only: true
+    - type: bind
+      source: ./keys
+      target: /data/keys
+      read_only: true
+    - type: bind
+      source: ./backup
+      target: /data/backup
+      read_only: false
+    command: /gobin/dgraph alpha -o 103 --my=alpha3:7183 --lru_mb=1024 --zero=zero1:5180
+      --logtostderr -v=2 --idx=3 --encryption_key_file /data/keys/enc_key
+      --whitelist=10.0.0.0/8,172.16.0.0/12,192.168.0.0/16
   ratel:
     image: dgraph/dgraph:latest
     container_name: ratel
@@ -47,6 +101,6 @@ services:
       source: $GOPATH/bin
       target: /gobin
       read_only: true
-    command: /gobin/dgraph zero -o 100 --idx=1 --my=zero1:5180 --logtostderr -v=2
-      --bindall
+    command: /gobin/dgraph zero -o 100 --idx=1 --my=zero1:5180 --replicas=1 --logtostderr
+      -v=2 --bindall
 volumes: {}

systest/online-restore/online_restore_test.go

@@ -37,7 +37,7 @@ import (
 
 func sendRestoreRequest(t *testing.T) {
 	restoreRequest := `mutation restore() {
-		 restore(input: {location: "/data/backup", backupId: "heuristic_sammet9",
+		 restore(input: {location: "/data/backup", backupId: "cranky_bartik8",
 		 	encryptionKeyFile: "/data/keys/enc_key"}) {
 			response {
 				code
@@ -190,7 +190,7 @@ func TestListBackups(t *testing.T) {
 	buf, err := ioutil.ReadAll(resp.Body)
 	require.NoError(t, err)
 	sbuf := string(buf)
-	require.Contains(t, sbuf, `"backupId":"heuristic_sammet9"`)
+	require.Contains(t, sbuf, `"backupId":"cranky_bartik8"`)
 	require.Contains(t, sbuf, `"backupNum":1`)
 	require.Contains(t, sbuf, `"backupNum":2`)
 	require.Contains(t, sbuf, "initial_release_date")

worker/online_restore_ee.go

@@ -231,6 +231,12 @@ func getEncConfig(req *pb.RestoreRequest) (*viper.Viper, error) {
 func writeBackup(ctx context.Context, req *pb.RestoreRequest) error {
 	res := LoadBackup(req.Location, req.BackupId,
 		func(r io.Reader, groupId uint32, preds predicateSet) (uint64, error) {
+			if groupId != req.GroupId {
+				// LoadBackup will try to call the backup function for every group.
+				// Exit here if the group is not the one indicated by the request.
+				return 0, nil
+			}
+
 			cfg, err := getEncConfig(req)
 			if err != nil {
 				return 0, errors.Wrapf(err, "unable to get encryption config")