frostfs-node/pkg/local_object_storage/shard/get.go

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package shard
import (
"fmt"
"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor"
"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/blobstor/common"
meta "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/metabase"
"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/util/logicerr"
"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/writecache"
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"
"go.uber.org/zap"
)
// storFetcher is a type to unify object fetching mechanism in `fetchObjectData`
// method. It represents generalization of `getSmall` and `getBig` methods.
type storFetcher = func(stor *blobstor.BlobStor, id []byte) (*objectSDK.Object, error)
// GetPrm groups the parameters of Get operation.
type GetPrm struct {
addr oid.Address
skipMeta bool
}
// GetRes groups the resulting values of Get operation.
type GetRes struct {
obj *objectSDK.Object
hasMeta bool
}
// SetAddress is a Get option to set the address of the requested object.
//
// Option is required.
func (p *GetPrm) SetAddress(addr oid.Address) {
p.addr = addr
}
// SetIgnoreMeta is a Get option try to fetch object from blobstor directly,
// without accessing metabase.
func (p *GetPrm) SetIgnoreMeta(ignore bool) {
p.skipMeta = ignore
}
// Object returns the requested object.
func (r GetRes) Object() *objectSDK.Object {
return r.obj
}
// HasMeta returns true if info about the object was found in the metabase.
func (r GetRes) HasMeta() bool {
return r.hasMeta
}
// Get reads an object from shard.
//
// Returns any error encountered that
// did not allow to completely read the object part.
//
// Returns an error of type apistatus.ObjectNotFound if the requested object is missing in shard.
// Returns an error of type apistatus.ObjectAlreadyRemoved if the requested object has been marked as removed in shard.
// Returns the object.ErrObjectIsExpired if the object is presented but already expired.
func (s *Shard) Get(prm GetPrm) (GetRes, error) {
s.m.RLock()
defer s.m.RUnlock()
cb := func(stor *blobstor.BlobStor, id []byte) (*objectSDK.Object, error) {
var getPrm common.GetPrm
getPrm.Address = prm.addr
getPrm.StorageID = id
res, err := stor.Get(getPrm)
if err != nil {
return nil, err
}
return res.Object, nil
}
wc := func(c writecache.Cache) (*objectSDK.Object, error) {
return c.Get(prm.addr)
}
skipMeta := prm.skipMeta || s.info.Mode.NoMetabase()
obj, hasMeta, err := s.fetchObjectData(prm.addr, skipMeta, cb, wc)
return GetRes{
obj: obj,
hasMeta: hasMeta,
}, err
}
// emptyStorageID is an empty storageID that indicates that
// an object is big (and is stored in an FSTree, not in a blobovnicza).
var emptyStorageID = make([]byte, 0)
// fetchObjectData looks through writeCache and blobStor to find object.
func (s *Shard) fetchObjectData(addr oid.Address, skipMeta bool, cb storFetcher, wc func(w writecache.Cache) (*objectSDK.Object, error)) (*objectSDK.Object, bool, error) {
var (
mErr error
mRes meta.ExistsRes
)
if !skipMeta {
var mPrm meta.ExistsPrm
mPrm.SetAddress(addr)
mRes, mErr = s.metaBase.Exists(mPrm)
if mErr != nil && !s.info.Mode.NoMetabase() {
return nil, false, mErr
}
if !mRes.Exists() {
return nil, false, logicerr.Wrap(apistatus.ObjectNotFound{})
}
} else {
s.log.Warn("fetching object without meta", zap.Stringer("addr", addr))
}
if s.hasWriteCache() {
res, err := wc(s.writeCache)
if err == nil || IsErrOutOfRange(err) {
return res, false, err
}
if IsErrNotFound(err) {
s.log.Debug("object is missing in write-cache",
zap.Stringer("addr", addr),
zap.Bool("skip_meta", skipMeta))
} else {
s.log.Error("failed to fetch object from write-cache",
zap.Error(err),
zap.Stringer("addr", addr),
zap.Bool("skip_meta", skipMeta))
}
}
if skipMeta || mErr != nil {
res, err := cb(s.blobStor, nil)
return res, false, err
}
var mPrm meta.StorageIDPrm
mPrm.SetAddress(addr)
mExRes, err := s.metaBase.StorageID(mPrm)
if err != nil {
return nil, true, fmt.Errorf("can't fetch blobovnicza id from metabase: %w", err)
}
storageID := mExRes.StorageID()
if storageID == nil {
// `nil` storageID returned without any error
// means that object is big, `cb` expects an
// empty (but non-nil) storageID in such cases
storageID = emptyStorageID
}
res, err := cb(s.blobStor, storageID)
return res, true, err
}