forked from TrueCloudLab/frostfs-node
7eedb23eb7
Dump contains magic and a list of objects prefixed by object size in bytes. We can't use proto-marshaled list because this requires having all dump in memory. Using TAR induces 512 byte overhead for each object which can be a problem in some cases. Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
102 lines
2 KiB
Go
102 lines
2 KiB
Go
package shard
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import (
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"encoding/binary"
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"errors"
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"io"
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"os"
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"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/blobstor"
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)
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var dumpMagic = []byte("NEOF")
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// EvacuatePrm groups the parameters of Evacuate operation.
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type EvacuatePrm struct {
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path string
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stream io.Writer
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}
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// WithPath is an Evacuate option to set the destination path.
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func (p *EvacuatePrm) WithPath(path string) *EvacuatePrm {
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p.path = path
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return p
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}
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// WithStream is an Evacuate option to set the destination stream.
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// It takes priority over `path` option.
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func (p *EvacuatePrm) WithStream(r io.Writer) *EvacuatePrm {
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p.stream = r
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return p
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}
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// EvacuateRes groups the result fields of Evacuate operation.
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type EvacuateRes struct {
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count int
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}
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// Count return amount of object written.
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func (r *EvacuateRes) Count() int {
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return r.count
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}
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var ErrMustBeReadOnly = errors.New("shard must be in read-only mode")
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// Evacuate dumps all objects from the shard to a file or stream.
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//
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// Returns any error encountered.
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func (s *Shard) Evacuate(prm *EvacuatePrm) (*EvacuateRes, error) {
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s.m.RLock()
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defer s.m.RUnlock()
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if s.info.Mode != ModeReadOnly {
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return nil, ErrMustBeReadOnly
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}
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w := prm.stream
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if w == nil {
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f, err := os.OpenFile(prm.path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0640)
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if err != nil {
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return nil, err
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}
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defer f.Close()
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w = f
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}
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_, err := w.Write(dumpMagic)
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if err != nil {
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return nil, err
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}
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var count int
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if s.hasWriteCache() {
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// TODO evacuate objects from write cache
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}
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var pi blobstor.IteratePrm
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pi.SetIterationHandler(func(elem blobstor.IterationElement) error {
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data := elem.ObjectData()
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var size [4]byte
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binary.LittleEndian.PutUint32(size[:], uint32(len(data)))
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if _, err := w.Write(size[:]); err != nil {
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return err
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}
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if _, err := w.Write(data); err != nil {
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return err
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}
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count++
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return nil
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})
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if _, err := s.blobStor.Iterate(pi); err != nil {
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return nil, err
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}
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return &EvacuateRes{count: count}, nil
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}
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