[#242] node: Add tracing spans

Add tracing spans for PUT requests.
Add tracing spans for DELETE requests.
Add tracing spans for SELECT requests.

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/local_object_storage/writecache/mode.go

@@ -1,12 +1,16 @@
 package writecache
 
 import (
+	"context"
 	"fmt"
 	"time"
 
+	"git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/pkg/tracing"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/internal/logs"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/shard/mode"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/util/logicerr"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
 )
 
 // ErrReadOnly is returned when Put/Write is performed in a read-only mode.
@@ -19,19 +23,25 @@ var ErrNotInitialized = logicerr.New("write-cache is not initialized yet")
 // When shard is put in read-only mode all objects in memory are flushed to disk
 // and all background jobs are suspended.
 func (c *cache) SetMode(m mode.Mode) error {
+	ctx, span := tracing.StartSpanFromContext(context.TODO(), "writecache.SetMode",
+		trace.WithAttributes(
+			attribute.String("mode", m.String()),
+		))
+	defer span.End()
+
 	c.modeMtx.Lock()
 	defer c.modeMtx.Unlock()
 
-	return c.setMode(m)
+	return c.setMode(ctx, m)
 }
 
 // setMode applies new mode. Must be called with cache.modeMtx lock taken.
-func (c *cache) setMode(m mode.Mode) error {
+func (c *cache) setMode(ctx context.Context, m mode.Mode) error {
 	var err error
 	turnOffMeta := m.NoMetabase()
 
 	if turnOffMeta && !c.mode.NoMetabase() {
-		err = c.flush(true)
+		err = c.flush(ctx, true)
 		if err != nil {
 			return err
 		}
@@ -45,7 +55,7 @@ func (c *cache) setMode(m mode.Mode) error {
 
 		defer func() {
 			if err == nil && !turnOffMeta {
-				c.initFlushMarks()
+				c.initFlushMarks(ctx)
 			}
 		}()
 	}