frostfs-api-go-pogpp/pkg/netmap/selector.go
Evgenii Stratonikov ea6b6adfe0 [#157] netmap: Fallback to using minimal backup factor
Use CBF=1 when strict policy can't be satisfied.

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
2020-12-01 13:33:11 +03:00

252 lines
6.1 KiB
Go

package netmap
import (
"fmt"
"sort"
"github.com/nspcc-dev/hrw"
"github.com/nspcc-dev/neofs-api-go/v2/netmap"
)
// Selector represents v2-compatible netmap selector.
type Selector netmap.Selector
// processSelectors processes selectors and returns error is any of them is invalid.
func (c *Context) processSelectors(p *PlacementPolicy) error {
for _, s := range p.Selectors() {
if s == nil {
return fmt.Errorf("%w: SELECT", ErrMissingField)
} else if s.Filter() != MainFilterName {
_, ok := c.Filters[s.Filter()]
if !ok {
return fmt.Errorf("%w: SELECT FROM '%s'", ErrFilterNotFound, s.Filter())
}
}
c.Selectors[s.Name()] = s
result, err := c.getSelection(p, s)
if err != nil {
return err
}
c.Selections[s.Name()] = result
}
return nil
}
// GetNodesCount returns amount of buckets and minimum number of nodes in every bucket
// for the given selector.
func GetNodesCount(_ *PlacementPolicy, s *Selector) (int, int) {
switch s.Clause() {
case ClauseSame:
return 1, int(s.Count())
default:
return int(s.Count()), 1
}
}
// getSelection returns nodes grouped by s.attribute.
func (c *Context) getSelection(p *PlacementPolicy, s *Selector) ([]Nodes, error) {
bucketCount, nodesInBucket := GetNodesCount(p, s)
buckets := c.getSelectionBase(s)
if len(buckets) < bucketCount {
return nil, fmt.Errorf("%w: '%s'", ErrNotEnoughNodes, s.Name())
}
if len(c.pivot) == 0 {
// Deterministic order in case of zero seed.
if s.Attribute() == "" {
sort.Slice(buckets, func(i, j int) bool {
return buckets[i].nodes[0].ID < buckets[j].nodes[0].ID
})
} else {
sort.Slice(buckets, func(i, j int) bool {
return buckets[i].attr < buckets[j].attr
})
}
}
maxNodesInBucket := nodesInBucket * int(p.ContainerBackupFactor())
nodes := make([]Nodes, 0, len(buckets))
fallback := make([]Nodes, 0, len(buckets))
for i := range buckets {
ns := buckets[i].nodes
if len(ns) >= maxNodesInBucket {
nodes = append(nodes, ns[:maxNodesInBucket])
} else if len(ns) >= nodesInBucket {
fallback = append(fallback, ns)
}
}
if len(nodes) < bucketCount {
// Fallback to using minimum allowed backup factor (1).
nodes = append(nodes, fallback...)
if len(nodes) < bucketCount {
return nil, fmt.Errorf("%w: '%s'", ErrNotEnoughNodes, s.Name())
}
}
if len(c.pivot) != 0 {
weights := make([]float64, len(nodes))
for i := range nodes {
weights[i] = GetBucketWeight(nodes[i], c.aggregator(), c.weightFunc)
}
hrw.SortSliceByWeightIndex(nodes, weights, c.pivotHash)
}
return nodes[:bucketCount], nil
}
type nodeAttrPair struct {
attr string
nodes Nodes
}
// getSelectionBase returns nodes grouped by selector attribute.
// It it guaranteed that each pair will contain at least one node.
func (c *Context) getSelectionBase(s *Selector) []nodeAttrPair {
f := c.Filters[s.Filter()]
isMain := s.Filter() == MainFilterName
result := []nodeAttrPair{}
nodeMap := map[string]Nodes{}
attr := s.Attribute()
for i := range c.Netmap.Nodes {
if isMain || c.match(f, c.Netmap.Nodes[i]) {
if attr == "" {
// Default attribute is transparent identifier which is different for every node.
result = append(result, nodeAttrPair{attr: "", nodes: Nodes{c.Netmap.Nodes[i]}})
} else {
v := c.Netmap.Nodes[i].Attribute(attr)
nodeMap[v] = append(nodeMap[v], c.Netmap.Nodes[i])
}
}
}
if attr != "" {
for k, ns := range nodeMap {
result = append(result, nodeAttrPair{attr: k, nodes: ns})
}
}
if len(c.pivot) != 0 {
for i := range result {
hrw.SortSliceByWeightValue(result[i].nodes, result[i].nodes.Weights(c.weightFunc), c.pivotHash)
}
}
return result
}
// NewSelector creates and returns new Selector instance.
func NewSelector() *Selector {
return NewSelectorFromV2(new(netmap.Selector))
}
// NewSelectorFromV2 converts v2 Selector to Selector.
func NewSelectorFromV2(f *netmap.Selector) *Selector {
return (*Selector)(f)
}
// ToV2 converts Selector to v2 Selector.
func (s *Selector) ToV2() *netmap.Selector {
return (*netmap.Selector)(s)
}
// Name returns selector name.
func (s *Selector) Name() string {
return (*netmap.Selector)(s).
GetName()
}
// SetName sets selector name.
func (s *Selector) SetName(name string) {
(*netmap.Selector)(s).
SetName(name)
}
// Count returns count of nodes to select from bucket.
func (s *Selector) Count() uint32 {
return (*netmap.Selector)(s).
GetCount()
}
// SetCount sets count of nodes to select from bucket.
func (s *Selector) SetCount(c uint32) {
(*netmap.Selector)(s).
SetCount(c)
}
// Clause returns modifier showing how to form a bucket.
func (s *Selector) Clause() Clause {
return ClauseFromV2(
(*netmap.Selector)(s).
GetClause(),
)
}
// SetClause sets modifier showing how to form a bucket.
func (s *Selector) SetClause(c Clause) {
(*netmap.Selector)(s).
SetClause(c.ToV2())
}
// Attribute returns attribute bucket to select from.
func (s *Selector) Attribute() string {
return (*netmap.Selector)(s).
GetAttribute()
}
// SetAttribute sets attribute bucket to select from.
func (s *Selector) SetAttribute(a string) {
(*netmap.Selector)(s).
SetAttribute(a)
}
// Filter returns filter reference to select from.
func (s *Selector) Filter() string {
return (*netmap.Selector)(s).
GetFilter()
}
// SetFilter sets filter reference to select from.
func (s *Selector) SetFilter(f string) {
(*netmap.Selector)(s).
SetFilter(f)
}
// Marshal marshals Selector into a protobuf binary form.
//
// Buffer is allocated when the argument is empty.
// Otherwise, the first buffer is used.
func (s *Selector) Marshal(b ...[]byte) ([]byte, error) {
var buf []byte
if len(b) > 0 {
buf = b[0]
}
return (*netmap.Selector)(s).StableMarshal(buf)
}
// Unmarshal unmarshals protobuf binary representation of Selector.
func (s *Selector) Unmarshal(data []byte) error {
return (*netmap.Selector)(s).
Unmarshal(data)
}
// MarshalJSON encodes Selector to protobuf JSON format.
func (s *Selector) MarshalJSON() ([]byte, error) {
return (*netmap.Selector)(s).
MarshalJSON()
}
// UnmarshalJSON decodes Selector from protobuf JSON format.
func (s *Selector) UnmarshalJSON(data []byte) error {
return (*netmap.Selector)(s).
UnmarshalJSON(data)
}