frostfs-node/pkg/local_object_storage/shard/get.go
Leonard Lyubich 318639e5bf [#1247] *: Clarify docs about returned errors from apistatus package
`apistatus` package provides types which implement build-in `error`
interface. Add `error of type` pattern when documenting these errors in
order to clarify how these errors should be handled (e.g. `errors.Is` is
not good).

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
2022-03-17 16:34:00 +03:00

157 lines
4 KiB
Go

package shard
import (
"errors"
"fmt"
"github.com/nspcc-dev/neofs-node/pkg/core/object"
"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/blobovnicza"
"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/blobstor"
meta "github.com/nspcc-dev/neofs-node/pkg/local_object_storage/metabase"
"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/writecache"
apistatus "github.com/nspcc-dev/neofs-sdk-go/client/status"
objectSDK "github.com/nspcc-dev/neofs-sdk-go/object"
addressSDK "github.com/nspcc-dev/neofs-sdk-go/object/address"
"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 *blobovnicza.ID) (*objectSDK.Object, error)
// GetPrm groups the parameters of Get operation.
type GetPrm struct {
addr *addressSDK.Address
skipMeta bool
}
// GetRes groups resulting values of Get operation.
type GetRes struct {
obj *objectSDK.Object
hasMeta bool
}
// WithAddress is a Get option to set the address of the requested object.
//
// Option is required.
func (p *GetPrm) WithAddress(addr *addressSDK.Address) *GetPrm {
if p != nil {
p.addr = addr
}
return p
}
// WithIgnoreMeta is a Get option try to fetch object from blobstor directly,
// without accessing metabase.
func (p *GetPrm) WithIgnoreMeta(ignore bool) *GetPrm {
p.skipMeta = ignore
return p
}
// 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 requested object is missing in shard.
// Returns an error of type apistatus.ObjectAlreadyRemoved if requested object has been marked as removed in shard.
func (s *Shard) Get(prm *GetPrm) (*GetRes, error) {
var big, small storFetcher
big = func(stor *blobstor.BlobStor, _ *blobovnicza.ID) (*objectSDK.Object, error) {
getBigPrm := new(blobstor.GetBigPrm)
getBigPrm.SetAddress(prm.addr)
res, err := stor.GetBig(getBigPrm)
if err != nil {
return nil, err
}
return res.Object(), nil
}
small = func(stor *blobstor.BlobStor, id *blobovnicza.ID) (*objectSDK.Object, error) {
getSmallPrm := new(blobstor.GetSmallPrm)
getSmallPrm.SetAddress(prm.addr)
getSmallPrm.SetBlobovniczaID(id)
res, err := stor.GetSmall(getSmallPrm)
if err != nil {
return nil, err
}
return res.Object(), nil
}
obj, hasMeta, err := s.fetchObjectData(prm.addr, prm.skipMeta, big, small)
return &GetRes{
obj: obj,
hasMeta: hasMeta,
}, err
}
// fetchObjectData looks through writeCache and blobStor to find object.
func (s *Shard) fetchObjectData(addr *addressSDK.Address, skipMeta bool, big, small storFetcher) (*objectSDK.Object, bool, error) {
var (
err error
res *objectSDK.Object
)
if s.hasWriteCache() {
res, err = s.writeCache.Get(addr)
if err == nil {
return res, false, nil
}
if writecache.IsErrNotFound(err) {
s.log.Debug("object is missing in write-cache")
} else {
s.log.Error("failed to fetch object from write-cache", zap.Error(err))
}
}
if skipMeta {
res, err = small(s.blobStor, nil)
if err == nil || errors.Is(err, object.ErrRangeOutOfBounds) {
return res, false, err
}
res, err = big(s.blobStor, nil)
return res, false, err
}
exists, err := meta.Exists(s.metaBase, addr)
if err != nil {
return nil, false, err
}
if !exists {
var errNotFound apistatus.ObjectNotFound
return nil, false, errNotFound
}
blobovniczaID, err := meta.IsSmall(s.metaBase, addr)
if err != nil {
return nil, true, fmt.Errorf("can't fetch blobovnicza id from metabase: %w", err)
}
if blobovniczaID != nil {
res, err = small(s.blobStor, blobovniczaID)
} else {
res, err = big(s.blobStor, nil)
}
return res, true, err
}