/
ulimit_unix.go
101 lines (79 loc) · 2.46 KB
/
ulimit_unix.go
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//go:build darwin || linux
package cmd
import (
"fmt"
"syscall"
zerolog "github.com/rs/zerolog/log"
)
const ulimitUnix uint64 = 16384
func init() {
fileDescriptorF = checkAndSetUlimitUnix
}
// In this entire file, by 'ulimit' we mean the "num open files ulimit" (RLIMIT_NOFILE)
func checkAndSetUlimitUnix() {
logger := zerolog.Logger
rlimit, err := getUlimit()
if err != nil {
logger.Err(err).Msg("checkAndSetUlimitUnix: failed getting ulimit")
return
}
logger.Info().Uint64("hard_ulimit", rlimit.Max).Uint64("soft_ulimit", rlimit.Cur).Msg("limits (before adjustment)")
if err := setUlimit(); err != nil {
logger.Err(err).Msg("failed setting ulimit")
}
rlimit, err = getUlimit()
if err != nil {
logger.Err(err).Msg("checkAndSetUlimitUnix: failed getting ulimit")
return
}
logger.Info().Uint64("hard_ulimit", rlimit.Max).Uint64("soft_ulimit", rlimit.Cur).Msg("limits (after adjustment)")
}
func setUlimit() error {
logger := zerolog.Logger
// Setting the hard ulimit is very likely to fail (usually requires root or even more arcane permissions).
// If it fails we just log at "INFO" level.
if err := setHardUlimit(); err != nil {
// Just an info log here, since it's really not actionable.
logger.Info().AnErr("err", err).Msg("failed setting hard ulimit")
}
return setSoftUlimit()
}
func setHardUlimit() error {
logger := zerolog.Logger
rLimit, err := getUlimit()
if err != nil {
return fmt.Errorf("setHardUlimit: error getting ulimit: %w", err)
}
if rLimit.Max < ulimitUnix {
logger.Info().Uint64("previous_ulimit", rLimit.Max).Uint64("new_ulimit", ulimitUnix).Msg("adjusting hard ulimit")
rLimit.Max = ulimitUnix
return syscall.Setrlimit(syscall.RLIMIT_NOFILE, &rLimit)
}
return nil
}
func setSoftUlimit() error {
logger := zerolog.Logger
rlimit, err := getUlimit()
if err != nil {
return fmt.Errorf("setSoftUlimit: error getting ulimit: %w", err)
}
desiredUlimit := min(rlimit.Max, ulimitUnix)
if rlimit.Cur < desiredUlimit {
logger.Info().Uint64("previous_ulimit", rlimit.Cur).Uint64("new_ulimit", desiredUlimit).Msg("adjusting soft ulimit")
rlimit.Cur = desiredUlimit
return syscall.Setrlimit(syscall.RLIMIT_NOFILE, &rlimit)
}
return nil
}
func getUlimit() (syscall.Rlimit, error) {
var rLimit syscall.Rlimit
err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rLimit)
return rLimit, err
}
// Golang doesn't have an out-of-the-box min function xd
func min(a uint64, b uint64) uint64 {
if a < b {
return a
}
return b
}