[#1502] Use zap.Error for logging errors

Use `zap.Error` instead of `zap.String` for logging errors: change all expressions like
`zap.String("error", err.Error())` or `zap.String("err", err.Error())` to `zap.Error(err)`.
Leave similar expressions with other messages unchanged, for example,
`zap.String("last_error", lastErr.Error())` or `zap.String("reason", ctx.Err().Error())`.

This change was made by applying the following patch:
```diff
@@
var err expression
@@
-zap.String("error", err.Error())
+zap.Error(err)

@@
var err expression
@@
-zap.String("err", err.Error())
+zap.Error(err)
```

Signed-off-by: Aleksey Savchuk <a.savchuk@yadro.com>

cmd/frostfs-ir/httpcomponent.go

@@ -77,7 +77,7 @@ func (c *httpComponent) reload(ctx context.Context) {
 		log.Info(ctx, c.name+" config updated")
 		if err := c.shutdown(ctx); err != nil {
 			log.Debug(ctx, logs.FrostFSIRCouldNotShutdownHTTPServer,
-				zap.String("error", err.Error()),
+				zap.Error(err),
 			)
 		} else {
 			c.init(ctx)

cmd/frostfs-ir/main.go

@@ -119,12 +119,12 @@ func shutdown(ctx context.Context) {
 	innerRing.Stop(ctx)
 	if err := metricsCmp.shutdown(ctx); err != nil {
 		log.Debug(ctx, logs.FrostFSIRCouldNotShutdownHTTPServer,
-			zap.String("error", err.Error()),
+			zap.Error(err),
 		)
 	}
 	if err := pprofCmp.shutdown(ctx); err != nil {
 		log.Debug(ctx, logs.FrostFSIRCouldNotShutdownHTTPServer,
-			zap.String("error", err.Error()),
+			zap.Error(err),
 		)
 	}
 

cmd/frostfs-ir/pprof.go

@@ -58,7 +58,7 @@ func (c *pprofComponent) reload(ctx context.Context) {
 		log.Info(ctx, c.name+" config updated")
 		if err := c.shutdown(ctx); err != nil {
 			log.Debug(ctx, logs.FrostFSIRCouldNotShutdownHTTPServer,
-				zap.String("error", err.Error()))
+				zap.Error(err))
 			return
 		}
 

cmd/frostfs-node/config.go

@@ -1119,7 +1119,7 @@ func initLocalStorage(ctx context.Context, c *cfg) {
 		err := ls.Close(context.WithoutCancel(ctx))
 		if err != nil {
 			c.log.Info(ctx, logs.FrostFSNodeStorageEngineClosingFailure,
-				zap.String("error", err.Error()),
+				zap.Error(err),
 			)
 		} else {
 			c.log.Info(ctx, logs.FrostFSNodeAllComponentsOfTheStorageEngineClosedSuccessfully)
@@ -1209,7 +1209,7 @@ func (c *cfg) updateContractNodeInfo(ctx context.Context, epoch uint64) {
 	if err != nil {
 		c.log.Error(ctx, logs.FrostFSNodeCouldNotUpdateNodeStateOnNewEpoch,
 			zap.Uint64("epoch", epoch),
-			zap.String("error", err.Error()))
+			zap.Error(err))
 		return
 	}
 

cmd/frostfs-node/main.go

@@ -134,7 +134,7 @@ func stopAndLog(ctx context.Context, c *cfg, name string, stopper func(context.C
 	err := stopper(ctx)
 	if err != nil {
 		c.log.Debug(ctx, fmt.Sprintf("could not shutdown %s server", name),
-			zap.String("error", err.Error()),
+			zap.Error(err),
 		)
 	}
 

cmd/frostfs-node/morph.go

@@ -96,7 +96,7 @@ func initMorphClient(ctx context.Context, c *cfg) {
 	if err != nil {
 		c.log.Info(ctx, logs.FrostFSNodeFailedToCreateNeoRPCClient,
 			zap.Any("endpoints", addresses),
-			zap.String("error", err.Error()),
+			zap.Error(err),
 		)
 
 		fatalOnErr(err)
@@ -168,7 +168,7 @@ func listenMorphNotifications(ctx context.Context, c *cfg) {
 	fromSideChainBlock, err := c.persistate.UInt32(persistateSideChainLastBlockKey)
 	if err != nil {
 		fromSideChainBlock = 0
-		c.log.Warn(ctx, logs.FrostFSNodeCantGetLastProcessedSideChainBlockNumber, zap.String("error", err.Error()))
+		c.log.Warn(ctx, logs.FrostFSNodeCantGetLastProcessedSideChainBlockNumber, zap.Error(err))
 	}
 
 	subs, err = subscriber.New(ctx, &subscriber.Params{

cmd/frostfs-node/netmap.go

@@ -197,7 +197,7 @@ func addNewEpochNotificationHandlers(c *cfg) {
 		_, _, err := makeNotaryDeposit(ctx, c)
 		if err != nil {
 			c.log.Error(ctx, logs.FrostFSNodeCouldNotMakeNotaryDeposit,
-				zap.String("error", err.Error()),
+				zap.Error(err),
 			)
 		}
 	})

cmd/frostfs-node/object.go

@@ -58,7 +58,7 @@ func (c *cfg) MaxObjectSize() uint64 {
 	sz, err := c.cfgNetmap.wrapper.MaxObjectSize()
 	if err != nil {
 		c.log.Error(context.Background(), logs.FrostFSNodeCouldNotGetMaxObjectSizeValue,
-			zap.String("error", err.Error()),
+			zap.Error(err),
 		)
 	}
 
@@ -269,7 +269,7 @@ func addPolicer(c *cfg, keyStorage *util.KeyStorage, clientConstructor *cache.Cl
 			_, err := ls.Inhume(ctx, inhumePrm)
 			if err != nil {
 				c.log.Warn(ctx, logs.FrostFSNodeCouldNotInhumeMarkRedundantCopyAsGarbage,
-					zap.String("error", err.Error()),
+					zap.Error(err),
 				)
 			}
 		}),

cmd/frostfs-node/tree.go

@@ -113,7 +113,7 @@ func initTreeService(c *cfg) {
 			// Ignore pilorama.ErrTreeNotFound but other errors, including shard.ErrReadOnly, should be logged.
 			c.log.Error(ctx, logs.FrostFSNodeContainerRemovalEventReceivedButTreesWerentRemoved,
 				zap.Stringer("cid", ev.ID),
-				zap.String("error", err.Error()))
+				zap.Error(err))
 		}
 	})