[#1532] node: Allow to omit metabase.path if shard is disabled

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

cmd/frostfs-node/config/engine/config.go

@@ -41,6 +41,10 @@ func IterateShards(c *config.Config, required bool, f func(*shardconfig.Config)
 			c.Sub(si),
 		)
 
+		if sc.Mode() == mode.Disabled {
+			continue
+		}
+
 		// Path for the blobstor can't be present in the default section, because different shards
 		// must have different paths, so if it is missing, the shard is not here.
 		// At the same time checking for "blobstor" section doesn't work proper
@@ -50,10 +54,6 @@ func IterateShards(c *config.Config, required bool, f func(*shardconfig.Config)
 		}
 		(*config.Config)(sc).SetDefault(def)
 
-		if sc.Mode() == mode.Disabled {
-			continue
-		}
-
 		if err := f(sc); err != nil {
 			return err
 		}

cmd/frostfs-node/config/engine/config_test.go

@@ -18,6 +18,22 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+func TestIterateShards(t *testing.T) {
+	fileConfigTest := func(c *config.Config) {
+		var res []string
+		require.NoError(t,
+			engineconfig.IterateShards(c, false, func(sc *shardconfig.Config) error {
+				res = append(res, sc.Metabase().Path())
+				return nil
+			}))
+		require.Equal(t, []string{"abc", "xyz"}, res)
+	}
+
+	const cfgDir = "./testdata/shards"
+	configtest.ForEachFileType(cfgDir, fileConfigTest)
+	configtest.ForEnvFileType(t, cfgDir, fileConfigTest)
+}
+
 func TestEngineSection(t *testing.T) {
 	t.Run("defaults", func(t *testing.T) {
 		empty := configtest.EmptyConfig()

cmd/frostfs-node/config/engine/testdata/shards.env

@@ -0,0 +1,3 @@
+FROSTFS_STORAGE_SHARD_0_METABASE_PATH=abc
+FROSTFS_STORAGE_SHARD_1_MODE=disabled
+FROSTFS_STORAGE_SHARD_2_METABASE_PATH=xyz

cmd/frostfs-node/config/engine/testdata/shards.json

@@ -0,0 +1,13 @@
+{
+  "storage.shard": {
+    "0": {
+      "metabase.path": "abc"
+    },
+    "1": {
+      "mode": "disabled"
+    },
+    "2": {
+      "metabase.path": "xyz"
+    }
+  }
+}

cmd/frostfs-node/config/engine/testdata/shards.yaml

@@ -0,0 +1,7 @@
+storage.shard:
+  0:
+    metabase.path: abc
+  1:
+    mode: disabled
+  2:
+    metabase.path: xyz