From 91137936880b9c88ad9c29281dd05d190233ea74 Mon Sep 17 00:00:00 2001
From: Evgenii Stratonikov <evgeniy@morphbits.ru>
Date: Tue, 20 Sep 2022 15:33:59 +0300
Subject: [PATCH] [#1764] neofs-node: Allow to return error from
 `IterateShards`

Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
---
 cmd/neofs-node/config.go                    |  8 ++++++--
 cmd/neofs-node/config/engine/config.go      | 13 ++++++++++---
 cmd/neofs-node/config/engine/config_test.go | 19 ++++++++++---------
 3 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/cmd/neofs-node/config.go b/cmd/neofs-node/config.go
index c11322e3b..3b2583ee4 100644
--- a/cmd/neofs-node/config.go
+++ b/cmd/neofs-node/config.go
@@ -409,7 +409,7 @@ func initShardOptions(c *cfg) {
 
 	require := !nodeconfig.Relay(c.appCfg) // relay node does not require shards
 
-	engineconfig.IterateShards(c.appCfg, require, func(sc *shardconfig.Config) {
+	err := engineconfig.IterateShards(c.appCfg, require, func(sc *shardconfig.Config) error {
 		var writeCacheOpts []writecache.Option
 
 		writeCacheCfg := sc.WriteCache()
@@ -474,7 +474,7 @@ func initShardOptions(c *cfg) {
 					},
 				})
 			default:
-				panic(fmt.Errorf("invalid storage type: %s", storages[i].Type()))
+				return fmt.Errorf("invalid storage type: %s", storages[i].Type())
 			}
 		}
 
@@ -521,7 +521,11 @@ func initShardOptions(c *cfg) {
 			}),
 			shard.WithGCEventChannel(gcEventChannel),
 		})
+		return nil
 	})
+	if err != nil {
+		panic(err)
+	}
 
 	c.cfgObject.cfgLocalStorage.shardOpts = opts
 }
diff --git a/cmd/neofs-node/config/engine/config.go b/cmd/neofs-node/config/engine/config.go
index 37b6f1c33..0fc9e01eb 100644
--- a/cmd/neofs-node/config/engine/config.go
+++ b/cmd/neofs-node/config/engine/config.go
@@ -1,6 +1,7 @@
 package engineconfig
 
 import (
+	"errors"
 	"strconv"
 
 	"github.com/nspcc-dev/neofs-node/cmd/neofs-node/config"
@@ -15,13 +16,16 @@ const (
 	ShardPoolSizeDefault = 20
 )
 
+// ErrNoShardConfigured is returned when at least 1 shard is required but none are found.
+var ErrNoShardConfigured = errors.New("no shard configured")
+
 // IterateShards iterates over subsections of "shard" subsection of "storage" section of c,
 // wrap them into shardconfig.Config and passes to f.
 //
 // Section names are expected to be consecutive integer numbers, starting from 0.
 //
 // Panics if N is not a positive number while shards are required.
-func IterateShards(c *config.Config, required bool, f func(*shardconfig.Config)) {
+func IterateShards(c *config.Config, required bool, f func(*shardconfig.Config) error) error {
 	c = c.Sub(subsection)
 
 	c = c.Sub("shard")
@@ -44,11 +48,14 @@ func IterateShards(c *config.Config, required bool, f func(*shardconfig.Config))
 		}
 		(*config.Config)(sc).SetDefault(def)
 
-		f(sc)
+		if err := f(sc); err != nil {
+			return err
+		}
 	}
 	if i == 0 && required {
-		panic("no shard configured")
+		return ErrNoShardConfigured
 	}
+	return nil
 }
 
 // ShardPoolSize returns the value of "shard_pool_size" config parameter from "storage" section.
diff --git a/cmd/neofs-node/config/engine/config_test.go b/cmd/neofs-node/config/engine/config_test.go
index 7eef4eff2..fa0f656d1 100644
--- a/cmd/neofs-node/config/engine/config_test.go
+++ b/cmd/neofs-node/config/engine/config_test.go
@@ -20,17 +20,17 @@ func TestEngineSection(t *testing.T) {
 	t.Run("defaults", func(t *testing.T) {
 		empty := configtest.EmptyConfig()
 
-		require.Panics(t, func() {
-			engineconfig.IterateShards(empty, true, nil)
-		})
+		require.ErrorIs(t,
+			engineconfig.IterateShards(empty, true, nil),
+			engineconfig.ErrNoShardConfigured)
 
 		handlerCalled := false
 
-		require.NotPanics(t, func() {
-			engineconfig.IterateShards(empty, false, func(_ *shardconfig.Config) {
+		require.NoError(t,
+			engineconfig.IterateShards(empty, false, func(_ *shardconfig.Config) error {
 				handlerCalled = true
-			})
-		})
+				return nil
+			}))
 
 		require.False(t, handlerCalled)
 
@@ -47,7 +47,7 @@ func TestEngineSection(t *testing.T) {
 		require.EqualValues(t, 100, engineconfig.ShardErrorThreshold(c))
 		require.EqualValues(t, 15, engineconfig.ShardPoolSize(c))
 
-		engineconfig.IterateShards(c, true, func(sc *shardconfig.Config) {
+		err := engineconfig.IterateShards(c, true, func(sc *shardconfig.Config) error {
 			defer func() {
 				num++
 			}()
@@ -145,8 +145,9 @@ func TestEngineSection(t *testing.T) {
 				require.Equal(t, true, sc.RefillMetabase())
 				require.Equal(t, mode.ReadWrite, sc.Mode())
 			}
+			return nil
 		})
-
+		require.NoError(t, err)
 		require.Equal(t, 2, num)
 	}