frostfs-api-go-pogpp/pkg/netmap/selector.go

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package netmap
import (
"fmt"
"sort"
"github.com/nspcc-dev/hrw"
"github.com/nspcc-dev/neofs-api-go/v2/netmap"
)
// processSelectors processes selectors and returns error is any of them is invalid.
func (c *Context) processSelectors(p *netmap.PlacementPolicy) error {
for _, s := range p.GetSelectors() {
if s == nil {
return fmt.Errorf("%w: SELECT", ErrMissingField)
} else if s.GetFilter() != MainFilterName {
_, ok := c.Filters[s.GetFilter()]
if !ok {
return fmt.Errorf("%w: SELECT FROM '%s'", ErrFilterNotFound, s.GetFilter())
}
}
c.Selectors[s.GetName()] = s
result, err := c.getSelection(p, s)
if err != nil {
return err
}
c.Selections[s.GetName()] = result
}
return nil
}
// GetNodesCount returns amount of buckets and nodes in every bucket
// for a given placement policy.
func GetNodesCount(p *netmap.PlacementPolicy, s *netmap.Selector) (int, int) {
switch s.GetClause() {
case netmap.Same:
return 1, int(p.GetContainerBackupFactor() * s.GetCount())
default:
return int(s.GetCount()), int(p.GetContainerBackupFactor())
}
}
// getSelection returns nodes grouped by s.attribute.
func (c *Context) getSelection(p *netmap.PlacementPolicy, s *netmap.Selector) ([]Nodes, error) {
bucketCount, nodesInBucket := GetNodesCount(p, s)
buckets := c.getSelectionBase(s)
if len(buckets) < bucketCount {
return nil, fmt.Errorf("%w: '%s'", ErrNotEnoughNodes, s.GetName())
}
if len(c.pivot) == 0 {
// Deterministic order in case of zero seed.
if s.GetAttribute() == "" {
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
})
}
}
nodes := make([]Nodes, 0, len(buckets))
for i := range buckets {
ns := buckets[i].nodes
if len(ns) >= nodesInBucket {
nodes = append(nodes, ns[:nodesInBucket])
}
}
if len(nodes) < bucketCount {
return nil, fmt.Errorf("%w: '%s'", ErrNotEnoughNodes, s.GetName())
}
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 *netmap.Selector) []nodeAttrPair {
f := c.Filters[s.GetFilter()]
isMain := s.GetFilter() == MainFilterName
result := []nodeAttrPair{}
nodeMap := map[string]Nodes{}
attr := s.GetAttribute()
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
}