[#421] Try using badger for the write-cache

Signed-off-by: Alejandro Lopez <a.lopez@yadro.com>

pkg/local_object_storage/writecache/writecachebbolt/get.go

@@ -0,0 +1,102 @@
+package writecachebbolt
+
+import (
+	"context"
+	"time"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/common"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/internal/metaerr"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/util/logicerr"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/writecache"
+	"git.frostfs.info/TrueCloudLab/frostfs-observability/tracing"
+	apistatus "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client/status"
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
+	"github.com/nspcc-dev/neo-go/pkg/util/slice"
+	"go.etcd.io/bbolt"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// Get returns object from write-cache.
+//
+// Returns an error of type apistatus.ObjectNotFound if the requested object is missing in write-cache.
+func (c *cache) Get(ctx context.Context, addr oid.Address) (*objectSDK.Object, error) {
+	saddr := addr.EncodeToString()
+
+	ctx, span := tracing.StartSpanFromContext(ctx, "writecache.Get",
+		trace.WithAttributes(
+			attribute.String("address", saddr),
+		))
+	defer span.End()
+
+	obj, err := c.getInternal(ctx, saddr, addr)
+	return obj, metaerr.Wrap(err)
+}
+
+func (c *cache) getInternal(ctx context.Context, saddr string, addr oid.Address) (*objectSDK.Object, error) {
+	found := false
+	storageType := writecache.StorageTypeUndefined
+	startedAt := time.Now()
+	defer func() {
+		c.metrics.Get(time.Since(startedAt), found, storageType)
+	}()
+
+	value, err := Get(c.db, []byte(saddr))
+	if err == nil {
+		obj := objectSDK.New()
+		found = true
+		storageType = writecache.StorageTypeDB
+		return obj, obj.Unmarshal(value)
+	}
+
+	res, err := c.fsTree.Get(ctx, common.GetPrm{Address: addr})
+	if err != nil {
+		return nil, logicerr.Wrap(apistatus.ObjectNotFound{})
+	}
+
+	found = true
+	storageType = writecache.StorageTypeFSTree
+	return res.Object, nil
+}
+
+// Head returns object header from write-cache.
+//
+// Returns an error of type apistatus.ObjectNotFound if the requested object is missing in write-cache.
+func (c *cache) Head(ctx context.Context, addr oid.Address) (*objectSDK.Object, error) {
+	saddr := addr.EncodeToString()
+
+	ctx, span := tracing.StartSpanFromContext(ctx, "writecache.Head",
+		trace.WithAttributes(
+			attribute.String("address", saddr),
+		))
+	defer span.End()
+
+	obj, err := c.getInternal(ctx, saddr, addr)
+	if err != nil {
+		return nil, metaerr.Wrap(err)
+	}
+
+	return obj.CutPayload(), nil
+}
+
+// Get fetches object from the underlying database.
+// Key should be a stringified address.
+//
+// Returns an error of type apistatus.ObjectNotFound if the requested object is missing in db.
+func Get(db *bbolt.DB, key []byte) ([]byte, error) {
+	var value []byte
+	err := db.View(func(tx *bbolt.Tx) error {
+		b := tx.Bucket(defaultBucket)
+		if b == nil {
+			return ErrNoDefaultBucket
+		}
+		value = b.Get(key)
+		if value == nil {
+			return logicerr.Wrap(apistatus.ObjectNotFound{})
+		}
+		value = slice.Copy(value)
+		return nil
+	})
+	return value, metaerr.Wrap(err)
+}