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package client
import (
"fmt"
"strconv"
"strings"
"github.com/mimecast/dtail/internal/io/dlog"
"github.com/mimecast/dtail/internal/mapr"
"github.com/mimecast/dtail/internal/protocol"
)
// Aggregate mapreduce data on the DTail client side.
type Aggregate struct {
// This represents aggregated data of a single remote server.
group *mapr.GroupSet
// Shared per-client session state.
session *SessionState
// The currently tracked shared generation.
generation uint64
// The server we aggregate the data for (logging and debugging purposes only)
server string
}
// NewAggregate create new client aggregator.
func NewAggregate(server string, session *SessionState) *Aggregate {
generation := uint64(0)
if session != nil {
generation = session.Snapshot().Generation
}
return &Aggregate{
group: mapr.NewGroupSet(),
session: session,
generation: generation,
server: server,
}
}
// Aggregate data from mapr log line into local (and global) group sets.
func (a *Aggregate) Aggregate(message string) error {
if a.session == nil {
return fmt.Errorf("missing client mapreduce session state")
}
snapshot := a.session.Snapshot()
if snapshot.Query == nil || snapshot.GlobalGroup == nil {
return fmt.Errorf("missing client mapreduce query state")
}
if snapshot.Generation != a.generation {
a.group.InitSet()
a.generation = snapshot.Generation
}
parts := strings.Split(message, protocol.AggregateDelimiter)
if len(parts) < 4 {
return fmt.Errorf("aggregate message without any real data")
}
groupKey := parts[0]
samples, err := strconv.Atoi(parts[1])
if err != nil {
return fmt.Errorf("unable to parse sample count '%s': %w", parts[1], err)
}
fields := a.makeFields(parts[2:])
set := a.group.GetSet(groupKey)
var addedSamples bool
for _, sc := range snapshot.Query.Select {
if val, ok := fields[sc.FieldStorage]; ok {
if err := set.Aggregate(sc.FieldStorage, sc.Operation, val, true); err != nil {
dlog.Client.Error(err)
continue
}
addedSamples = true
}
}
if addedSamples {
set.Samples += samples
}
// Merge data from group into global group.
isMerged, err := snapshot.GlobalGroup.MergeNoblock(snapshot.Query, a.group)
if err != nil {
return fmt.Errorf("unable to merge aggregate data for server %s: %w", a.server, err)
}
if isMerged {
// Re-init local group (make it empty again).
a.group.InitSet()
}
return nil
}
// Flush merges any pending per-server aggregate state into the shared global group.
// The normal hot path uses MergeNoblock to avoid stalling on the global merge lock.
// During shutdown we need a blocking flush so the last local batch is not lost.
func (a *Aggregate) Flush() error {
if a.session == nil {
return fmt.Errorf("missing client mapreduce session state")
}
snapshot := a.session.Snapshot()
if snapshot.Query == nil || snapshot.GlobalGroup == nil {
return nil
}
if snapshot.Generation != a.generation {
a.group.InitSet()
a.generation = snapshot.Generation
return nil
}
if err := snapshot.GlobalGroup.Merge(snapshot.Query, a.group); err != nil {
return fmt.Errorf("unable to flush aggregate data for server %s: %w", a.server, err)
}
a.group.InitSet()
return nil
}
// Create a map of key-value pairs from a part list such as ["foo=bar", "bar=baz"].
func (a *Aggregate) makeFields(parts []string) map[string]string {
fields := make(map[string]string, len(parts))
for _, part := range parts {
key, value, ok := strings.Cut(part, protocol.AggregateKVDelimiter)
if !ok {
continue
}
fields[key] = value
}
return fields
}
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