automemlimit

If cgroup limits are unavailable, you can use system memory limits. This can be done in two ways:

1. Environment Variable: Set AUTOMEMLIMIT_EXPERIMENT=system to enable experimental fallback to system memory limits.
2. Programmatically: Use memlimit.FromSystem as a provider, or use memlimit.ApplyFallback(memlimit.FromCgroup, memlimit.FromSystem) to attempt cgroup detection first and fall back to system limits if cgroups are not found.

The simplest way to use automemlimit is to import it with a blank identifier. This automatically sets GOMEMLIMIT to 90% of the Linux cgroup memory limit and enables default logging. This is equivalent to calling memlimit.SetGoMemLimitWithOpts(memlimit.WithLogger(slog.Default())).

package main

import _ "github.com/KimMachineGun/automemlimit"

To install automemlimit in your Go project, use the go get command:

go get github.com/KimMachineGun/automemlimit@latest

The automemlimit package provides a zero-configuration way to set the GOMEMLIMIT environment variable automatically by using a side-effect import. When you import the package, its init() function is executed, which calls memlimit.SetGoMemLimitWithOpts using the default slog logger. This is useful for applications that want to automatically adjust their memory limit based on the available system memory without manual configuration.

import _ "github.com/KimMachineGun/automemlimit/automemlimit"

The memlimit package provides several shorthand methods for setting the memory limit depending on your needs:

package main

import "github.com/KimMachineGun/automemlimit/memlimit"

func init() {
	// Set limit based on a ratio (e.g., 90%)
	memlimit.SetGoMemLimit(0.9)

	// Set limit with a specific provider and ratio
	memlimit.SetGoMemLimitWithProvider(memlimit.FromCgroup, 0.9)

	// Set limit with a hard limit value and a ratio
	memlimit.SetGoMemLimitWithProvider(memlimit.Limit(1024*1024), 0.9)

	// Specific Cgroup providers
	memlimit.SetGoMemLimitWithProvider(memlimit.FromCgroupV1, 0.9)
	memlimit.SetGoMemLimitWithProvider(memlimit.FromCgroupV2, 0.9)
	memlimit.SetGoMemLimitWithProvider(memlimit.FromCgroupHybrid, 0.9)
}

For fine-grained control, use the memlimit package. You can configure the memory limit ratio, the provider (where the limit is sourced from), logging, and how often the limit is refreshed.

package main

import "github.com/KimMachineGun/automemlimit/memlimit"
import "log/slog"
import "time"

func init() {
	// Example: Custom configuration with ratio, provider, logger, and refresh interval
	memlimit.SetGoMemLimitWithOpts(
		memlimit.WithRatio(0.9),
		memlimit.WithProvider(memlimit.FromCgroup),
		memlimit.WithLogger(slog.Default()),
		memlimit.WithRefreshInterval(1*time.Minute),
	)

	// Example: Using a fallback provider (Cgroup with System fallback)
	memlimit.SetGoMemLimitWithOpts(
		memlimit.WithRatio(0.9),
		memlimit.WithProvider(
			memlimit.ApplyFallback(
				memlimit.FromCgroup,
				memlimit.FromSystem,
			),
		),
		memlimit.WithRefreshInterval(1*time.Minute),
	)
}