memlimit

Documentation

Index

• Variables
• func FromCgroup() (uint64, error)
• func FromCgroupHybrid() (uint64, error)
• func FromCgroupV1() (uint64, error)
• func FromCgroupV2() (uint64, error)
• func FromSystem() (uint64, error)
• func Limit(limit uint64) func() (uint64, error)
• func SetGoMemLimit(ratio float64) (int64, error)
• func SetGoMemLimitWithEnv()
• func SetGoMemLimitWithOpts(opts ...Option) (_ int64, _err error)
• func SetGoMemLimitWithProvider(provider Provider, ratio float64) (int64, error)
• type Experiments
• type Option
  • func WithEnv() Option
  • func WithLogger(logger *slog.Logger) Option
  • func WithProvider(provider Provider) Option
  • func WithRatio(ratio float64) Option
  • func WithRefreshInterval(refresh time.Duration) Option
• type Provider
  • func ApplyFallback(provider Provider, fallback Provider) Provider
  • func ApplyRatio(provider Provider, ratio float64) Provider

Variables

var (
	// ErrNoCgroup is returned when the process is not in cgroup.
	ErrNoCgroup = errors.New("process is not in cgroup")
	// ErrCgroupsNotSupported is returned when the system does not support cgroups.
	ErrCgroupsNotSupported = errors.New("cgroups is not supported on this system")
)

var ErrNoLimit = errors.New("memory is not limited")

ErrNoLimit is returned when the memory limit is not set.

Functions

func FromCgroup

func FromCgroup() (uint64, error)

FromCgroup retrieves the memory limit from the cgroup.

func FromCgroupHybrid

func FromCgroupHybrid() (uint64, error)

FromCgroupHybrid retrieves the memory limit from the cgroup v2 and v1 controller sequentially, basically, it is equivalent to FromCgroup. After v1.0.0, this function could be removed and FromCgroup should be used instead.

func FromCgroupV1

func FromCgroupV1() (uint64, error)

FromCgroupV1 retrieves the memory limit from the cgroup v1 controller. After v1.0.0, this function could be removed and FromCgroup should be used instead.

func FromCgroupV2

func FromCgroupV2() (uint64, error)

FromCgroupV2 retrieves the memory limit from the cgroup v2 controller. After v1.0.0, this function could be removed and FromCgroup should be used instead.

func FromSystem

func FromSystem() (uint64, error)

FromSystem returns the total memory of the system.

func Limit

func Limit(limit uint64) func() (uint64, error)

Limit is a helper Provider function that returns the given limit.

func SetGoMemLimit

func SetGoMemLimit(ratio float64) (int64, error)

SetGoMemLimit sets GOMEMLIMIT with the value from the cgroup's memory limit and given ratio.

func SetGoMemLimitWithEnv

func SetGoMemLimitWithEnv()

SetGoMemLimitWithEnv sets GOMEMLIMIT with the value from the environment variables. Since WithEnv is deprecated, this function is equivalent to SetGoMemLimitWithOpts(). Deprecated: use SetGoMemLimitWithOpts instead.

func SetGoMemLimitWithOpts

func SetGoMemLimitWithOpts(opts ...Option) (_ int64, _err error)

SetGoMemLimitWithOpts sets GOMEMLIMIT with options and environment variables.

You can configure how much memory of the cgroup's memory limit to set as GOMEMLIMIT through AUTOMEMLIMIT environment variable in the half-open range (0.0,1.0].

If AUTOMEMLIMIT is not set, it defaults to 0.9. (10% is the headroom for memory sources the Go runtime is unaware of.) If GOMEMLIMIT is already set or AUTOMEMLIMIT=off, this function does nothing.

If AUTOMEMLIMIT_EXPERIMENT is set, it enables experimental features. Please see the documentation of Experiments for more details.

Options:

• WithRatio
• WithProvider
• WithLogger

func SetGoMemLimitWithProvider

func SetGoMemLimitWithProvider(provider Provider, ratio float64) (int64, error)

SetGoMemLimitWithProvider sets GOMEMLIMIT with the value from the given provider and ratio.

Types

type Experiments

type Experiments struct {
	// System enables fallback to system memory limit.
	System bool
}

Experiments is a set of experiment flags. It is used to enable experimental features.

You can set the flags by setting the environment variable AUTOMEMLIMIT_EXPERIMENT. The value of the environment variable is a comma-separated list of experiment names.

The following experiment names are known:

• none: disable all experiments
• system: enable fallback to system memory limit

type Option

type Option func(cfg *config)

Option is a function that configures the behavior of SetGoMemLimitWithOptions.

func WithEnv

func WithEnv() Option

WithEnv configures whether to use environment variables.

Default: false

Deprecated: currently this does nothing.

func WithLogger

func WithLogger(logger *slog.Logger) Option

WithLogger configures the logger. It automatically attaches the "package" attribute to the logs.

Default: slog.New(noopLogger{})

func WithProvider

func WithProvider(provider Provider) Option

WithProvider configures the provider.

Default: FromCgroup

func WithRatio

func WithRatio(ratio float64) Option

WithRatio configures the ratio of the memory limit to set as GOMEMLIMIT.

Default: 0.9

func WithRefreshInterval

func WithRefreshInterval(refresh time.Duration) Option

WithRefreshInterval configures the refresh interval for automemlimit. If a refresh interval is greater than 0, automemlimit periodically fetches the memory limit from the provider and reapplies it if it has changed. If the provider returns an error, it logs the error and continues. ErrNoLimit is treated as math.MaxInt64.

Default: 0 (no refresh)

type Provider

type Provider func() (uint64, error)

Provider is a function that returns the memory limit.

func ApplyFallback

func ApplyFallback(provider Provider, fallback Provider) Provider

ApplyFallback is a helper Provider function that sets the fallback provider.

func ApplyRatio

func ApplyRatio(provider Provider, ratio float64) Provider

ApplyRationA is a helper Provider function that applies the given ratio to the given provider.