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

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

pkg/local_object_storage/writecache/writecache.go

@@ -2,18 +2,14 @@ package writecache
 
 import (
 	"context"
-	"os"
-	"sync"
+	"errors"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/common"
-	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/fstree"
-	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/internal/metaerr"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/shard/mode"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/util/logicerr"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/logger"
 	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
 	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
-	"go.etcd.io/bbolt"
-	"go.uber.org/zap"
 )
 
 // Info groups the information about write-cache.
@@ -44,133 +40,13 @@ type Cache interface {
 	Close() error
 }
 
-type cache struct {
-	options
-
-	// mtx protects statistics, counters and compressFlags.
-	mtx sync.RWMutex
-
-	mode    mode.Mode
-	modeMtx sync.RWMutex
-
-	// compressFlags maps address of a big object to boolean value indicating
-	// whether object should be compressed.
-	compressFlags map[string]struct{}
-
-	// flushCh is a channel with objects to flush.
-	flushCh chan *objectSDK.Object
-	// closeCh is close channel, protected by modeMtx.
-	closeCh chan struct{}
-	// wg is a wait group for flush workers.
-	wg sync.WaitGroup
-	// store contains underlying database.
-	store
-	// fsTree contains big files stored directly on file-system.
-	fsTree *fstree.FSTree
-}
-
-// wcStorageType is used for write-cache operations logging.
-const wcStorageType = "write-cache"
-
-type objectInfo struct {
-	addr string
-	data []byte
-	obj  *objectSDK.Object
-}
-
-const (
-	defaultMaxObjectSize   = 64 * 1024 * 1024 // 64 MiB
-	defaultSmallObjectSize = 32 * 1024        // 32 KiB
-	defaultMaxCacheSize    = 1 << 30          // 1 GiB
-)
-
 var (
-	defaultBucket = []byte{0}
+	// ErrReadOnly is returned when Put/Write is performed in a read-only mode.
+	ErrReadOnly = logicerr.New("write-cache is in read-only mode")
+	// ErrNotInitialized is returned when write-cache is initializing.
+	ErrNotInitialized = logicerr.New("write-cache is not initialized yet")
+	// ErrBigObject is returned when object is too big to be placed in cache.
+	ErrBigObject = errors.New("too big object")
+	// ErrOutOfSpace is returned when there is no space left to put a new object.
+	ErrOutOfSpace = errors.New("no space left in the write cache")
 )
-
-// New creates new writecache instance.
-func New(opts ...Option) Cache {
-	c := &cache{
-		flushCh: make(chan *objectSDK.Object),
-		mode:    mode.ReadWrite,
-
-		compressFlags: make(map[string]struct{}),
-		options: options{
-			log:             &logger.Logger{Logger: zap.NewNop()},
-			maxObjectSize:   defaultMaxObjectSize,
-			smallObjectSize: defaultSmallObjectSize,
-			workersCount:    defaultFlushWorkersCount,
-			maxCacheSize:    defaultMaxCacheSize,
-			maxBatchSize:    bbolt.DefaultMaxBatchSize,
-			maxBatchDelay:   bbolt.DefaultMaxBatchDelay,
-			openFile:        os.OpenFile,
-			metrics:         &metricsStub{},
-		},
-	}
-
-	for i := range opts {
-		opts[i](&c.options)
-	}
-
-	return c
-}
-
-// SetLogger sets logger. It is used after the shard ID was generated to use it in logs.
-func (c *cache) SetLogger(l *logger.Logger) {
-	c.log = l
-}
-
-func (c *cache) DumpInfo() Info {
-	return Info{
-		Path: c.path,
-	}
-}
-
-// Open opens and initializes database. Reads object counters from the ObjectCounters instance.
-func (c *cache) Open(readOnly bool) error {
-	err := c.openStore(readOnly)
-	if err != nil {
-		return metaerr.Wrap(err)
-	}
-
-	// Opening after Close is done during maintenance mode,
-	// thus we need to create a channel here.
-	c.closeCh = make(chan struct{})
-
-	return metaerr.Wrap(c.initCounters())
-}
-
-// Init runs necessary services.
-func (c *cache) Init() error {
-	c.metrics.SetMode(c.mode)
-	c.runFlushLoop()
-	return nil
-}
-
-// Close closes db connection and stops services. Executes ObjectCounters.FlushAndClose op.
-func (c *cache) Close() error {
-	// We cannot lock mutex for the whole operation duration
-	// because it is taken by some background workers, so `wg.Wait()` is done without modeMtx.
-	c.modeMtx.Lock()
-	if c.closeCh != nil {
-		close(c.closeCh)
-	}
-	c.mode = mode.DegradedReadOnly // prevent new operations from being processed
-	c.modeMtx.Unlock()
-
-	c.wg.Wait()
-
-	c.modeMtx.Lock()
-	defer c.modeMtx.Unlock()
-
-	c.closeCh = nil
-	var err error
-	if c.db != nil {
-		err = c.db.Close()
-		if err != nil {
-			c.db = nil
-		}
-	}
-	c.metrics.Close()
-	return nil
-}