0g-chain/cmd/opendb/stat_parser.go

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//go:build rocksdb
// +build rocksdb
package opendb
import (
"fmt"
"strings"
"errors"
)
// stat represents one line from rocksdb statistics data, stat may have one or more properties
// examples:
// - rocksdb.block.cache.miss COUNT : 5
// - rocksdb.compaction.times.micros P50 : 21112 P95 : 21112 P99 : 21112 P100 : 21112 COUNT : 1 SUM : 21112
// `rocksdb.compaction.times.micros` is name of stat, P50, COUNT, SUM, etc... are props of stat
type stat struct {
name string
props map[string]string
}
// parseSerializedStats parses serialisedStats into map of stat objects
// example of serializedStats:
// rocksdb.block.cache.miss COUNT : 5
// rocksdb.compaction.times.micros P50 : 21112 P95 : 21112 P99 : 21112 P100 : 21112 COUNT : 1 SUM : 21112
func parseSerializedStats(serializedStats string) (map[string]*stat, error) {
stats := make(map[string]*stat, 0)
serializedStatList := strings.Split(serializedStats, "\n")
if len(serializedStatList) == 0 {
return nil, errors.New("serializedStats is empty")
}
serializedStatList = serializedStatList[:len(serializedStatList)-1]
// iterate over stats line by line
for _, serializedStat := range serializedStatList {
stat, err := parseSerializedStat(serializedStat)
if err != nil {
return nil, err
}
stats[stat.name] = stat
}
return stats, nil
}
// parseSerializedStat parses serialisedStat into stat object
// example of serializedStat:
// rocksdb.block.cache.miss COUNT : 5
func parseSerializedStat(serializedStat string) (*stat, error) {
tokens := strings.Split(serializedStat, " ")
tokensNum := len(tokens)
if err := validateTokens(tokens); err != nil {
return nil, fmt.Errorf("tokens are invalid: %v", err)
}
props := make(map[string]string)
for idx := 1; idx < tokensNum; idx += 3 {
// never should happen, but double check to avoid unexpected panic
if idx+2 >= tokensNum {
break
}
key := tokens[idx]
sep := tokens[idx+1]
value := tokens[idx+2]
if err := validateStatProperty(key, value, sep); err != nil {
return nil, fmt.Errorf("invalid stat property: %v", err)
}
props[key] = value
}
return &stat{
name: tokens[0],
props: props,
}, nil
}
// validateTokens validates that tokens contains name + N triples (key, sep, value)
func validateTokens(tokens []string) error {
tokensNum := len(tokens)
if tokensNum < 4 {
return fmt.Errorf("invalid number of tokens: %v, tokens: %v", tokensNum, tokens)
}
if (tokensNum-1)%3 != 0 {
return fmt.Errorf("invalid number of tokens: %v, tokens: %v", tokensNum, tokens)
}
if tokens[0] == "" {
return fmt.Errorf("stat name shouldn't be empty")
}
return nil
}
// validateStatProperty validates that key and value are divided by separator and aren't empty
func validateStatProperty(key, value, sep string) error {
if key == "" {
return fmt.Errorf("key shouldn't be empty")
}
if sep != ":" {
return fmt.Errorf("separator should be :")
}
if value == "" {
return fmt.Errorf("value shouldn't be empty")
}
return nil
}