Files
kubeshark/api/pkg/database/size_enforcer.go
2021-07-21 10:49:33 +03:00

122 lines
3.3 KiB
Go

package database
import (
"fmt"
"github.com/fsnotify/fsnotify"
"github.com/up9inc/mizu/shared"
"github.com/up9inc/mizu/shared/debounce"
"github.com/up9inc/mizu/shared/units"
"log"
"mizuserver/pkg/models"
"os"
"strconv"
"time"
)
const percentageOfMaxSizeBytesToPrune = 15
const defaultMaxDatabaseSizeBytes int64 = 200 * 1000 * 1000
func StartEnforcingDatabaseSize() {
watcher, err := fsnotify.NewWatcher()
if err != nil {
log.Fatalf("Error creating filesystem watcher for db size enforcement: %v\n", err)
return
}
maxEntriesDBByteSize, err := getMaxEntriesDBByteSize()
if err != nil {
log.Fatalf("Error parsing max db size: %v\n", err)
return
}
checkFileSizeDebouncer := debounce.NewDebouncer(5*time.Second, func() {
checkFileSize(maxEntriesDBByteSize)
})
go func() {
for {
select {
case event, ok := <-watcher.Events:
if !ok {
return // closed channel
}
if event.Op == fsnotify.Write {
checkFileSizeDebouncer.SetOn()
}
case err, ok := <-watcher.Errors:
if !ok {
return // closed channel
}
fmt.Printf("filesystem watcher encountered error:%v\n", err)
}
}
}()
err = watcher.Add(DBPath)
if err != nil {
log.Fatalf("Error adding %s to filesystem watcher for db size enforcement: %v\n", DBPath, err)
}
}
func getMaxEntriesDBByteSize() (int64, error) {
maxEntriesDBByteSize := defaultMaxDatabaseSizeBytes
var err error
maxEntriesDBSizeByteSEnvVarValue := os.Getenv(shared.MaxEntriesDBSizeBytesEnvVar)
if maxEntriesDBSizeByteSEnvVarValue != "" {
maxEntriesDBByteSize, err = strconv.ParseInt(maxEntriesDBSizeByteSEnvVarValue, 10, 64)
}
return maxEntriesDBByteSize, err
}
func checkFileSize(maxSizeBytes int64) {
fileStat, err := os.Stat(DBPath)
if err != nil {
fmt.Printf("Error checking %s file size: %v\n", DBPath, err)
} else {
if fileStat.Size() > maxSizeBytes {
pruneOldEntries(fileStat.Size())
}
}
}
func pruneOldEntries(currentFileSize int64) {
// sqlite locks the database while delete or VACUUM are running and sqlite is terrible at handling its own db lock while a lot of inserts are attempted, we prevent a significant bottleneck by handling the db lock ourselves here
IsDBLocked = true
defer func() {IsDBLocked = false}()
amountOfBytesToTrim := currentFileSize / (100 / percentageOfMaxSizeBytesToPrune)
rows, err := GetEntriesTable().Limit(10000).Order("id").Rows()
if err != nil {
fmt.Printf("Error getting 10000 first db rows: %v\n", err)
return
}
entryIdsToRemove := make([]uint, 0)
bytesToBeRemoved := int64(0)
for rows.Next() {
if bytesToBeRemoved >= amountOfBytesToTrim {
break
}
var entry models.MizuEntry
err = DB.ScanRows(rows, &entry)
if err != nil {
fmt.Printf("Error scanning db row: %v\n", err)
continue
}
entryIdsToRemove = append(entryIdsToRemove, entry.ID)
bytesToBeRemoved += int64(entry.EstimatedSizeBytes)
}
if len(entryIdsToRemove) > 0 {
GetEntriesTable().Where(entryIdsToRemove).Delete(models.MizuEntry{})
// VACUUM causes sqlite to shrink the db file after rows have been deleted, the db file will not shrink without this
DB.Exec("VACUUM")
fmt.Printf("Removed %d rows and cleared %s\n", len(entryIdsToRemove), units.BytesToHumanReadable(bytesToBeRemoved))
} else {
fmt.Println("Found no rows to remove when pruning")
}
}