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|
package mapr
import (
"context"
"encoding/base64"
"fmt"
"strconv"
"strings"
)
// AggregateSet represents aggregated key/value pairs from the
// MAPREDUCE log lines. These could be either string values or float
// values.
type AggregateSet struct {
Samples int
FValues map[string]float64
SValues map[string]string
}
// NewAggregateSet creates a new empty aggregate set.
func NewAggregateSet() *AggregateSet {
return &AggregateSet{
FValues: make(map[string]float64),
SValues: make(map[string]string),
}
}
// String representation of aggregate set.
func (s *AggregateSet) String() string {
return fmt.Sprintf("AggregateSet(Samples:%d,FValues:%v,SValues:%v)",
s.Samples, s.FValues, s.SValues)
}
// Merge one aggregate set into this one.
func (s *AggregateSet) Merge(query *Query, set *AggregateSet) error {
s.Samples += set.Samples
//logger.Trace("Merge", set)
for _, sc := range query.Select {
storage := sc.FieldStorage
switch sc.Operation {
case Count:
fallthrough
case Sum:
fallthrough
case Avg:
value := set.FValues[storage]
s.addFloat(storage, value)
case Min:
value := set.FValues[storage]
s.addFloatMin(storage, value)
case Max:
value := set.FValues[storage]
s.addFloatMax(storage, value)
case Last:
value := set.SValues[storage]
s.setString(storage, value)
case Len:
s.setString(storage, set.SValues[storage])
s.setFloat(storage, set.FValues[storage])
default:
return fmt.Errorf("Unknown aggregation method '%v'", sc.Operation)
}
}
return nil
}
// Serialize the aggregate set so it can be sent over the wire.
func (s *AggregateSet) Serialize(ctx context.Context, groupKey string, ch chan<- string) {
//logger.Trace("Serialising mapr.AggregateSet", s)
var sb strings.Builder
sb.WriteString(groupKey)
sb.WriteString("|")
sb.WriteString(fmt.Sprintf("%d|", s.Samples))
for k, v := range s.FValues {
sb.WriteString(k)
sb.WriteString("=")
sb.WriteString(fmt.Sprintf("%v|", v))
}
for k, v := range s.SValues {
sb.WriteString(k)
sb.WriteString("=")
if k == "$line" {
sb.WriteString(base64.StdEncoding.EncodeToString([]byte(v)))
sb.WriteString("|")
continue
}
sb.WriteString(v)
sb.WriteString("|")
}
select {
case ch <- sb.String():
case <-ctx.Done():
}
}
// Add a float value.
func (s *AggregateSet) addFloat(key string, value float64) {
if _, ok := s.FValues[key]; !ok {
s.FValues[key] = value
return
}
s.FValues[key] += value
}
// Add a float minimum value.
func (s *AggregateSet) addFloatMin(key string, value float64) {
f, ok := s.FValues[key]
if !ok {
s.FValues[key] = value
return
}
if f > value {
s.FValues[key] = value
}
}
// Add a float maximum value.
func (s *AggregateSet) addFloatMax(key string, value float64) {
f, ok := s.FValues[key]
if !ok {
s.FValues[key] = value
return
}
if f < value {
s.FValues[key] = value
}
}
// Set a string.
func (s *AggregateSet) setString(key, value string) {
s.SValues[key] = value
}
// Set a float.
func (s *AggregateSet) setFloat(key string, value float64) {
s.FValues[key] = value
}
// Aggregate data to the aggregate set.
func (s *AggregateSet) Aggregate(key string, agg AggregateOperation, value string, clientAggregation bool) (err error) {
var f float64
// First check if we can aggregate anything without converting value to float.
switch agg {
case Count:
if clientAggregation {
f, err = strconv.ParseFloat(value, 64)
if err != nil {
return
}
s.addFloat(key, f)
return
}
s.addFloat(key, 1)
return
case Last:
s.setString(key, value)
return
case Len:
s.setString(key, value)
s.setFloat(key, float64(len(value)))
return
default:
}
// No, we have to convert to float.
f, err = strconv.ParseFloat(value, 64)
if err != nil {
return
}
switch agg {
case Sum:
fallthrough
case Avg:
s.addFloat(key, f)
case Min:
s.addFloatMin(key, f)
case Max:
s.addFloatMax(key, f)
default:
err = fmt.Errorf("Unknown aggregation method '%v'", agg)
}
return
}
|
