🫶 Add new SetGoMemLimitWithOptions

[mirecl]

✅ Add configure options for SetGoMemLimitWithEnv:

• WithLogger (Please consider logging by default #5);
• WithProvider;
• WithEnv;
• WithRatio.

❗For example:

logger, _ := zap.NewProduction()
sugar := logger.Sugar()

memlimit.SetGoMemLimitWithOptions(
   memlimit.WithLogger(sugar.Debugf), // default: `log.Printf`
   memlimit.WithProvider(memlimit.FromCgroupV1), // default: `memlimit.FromCgroup`
   memlimit.WithRatio(.8), // default: `0.9`
   memlimit.WithEnv(), // default: `false`
)

P.S. I am confident that this commit will be beneficial for the community.

[mirecl]

@KimMachineGun, what do you think about it?

[KimMachineGun]

Thank you for your contribution.
The idea seems great!

[KimMachineGun]

The logging patterns will be changed after the Go 1.21 release to use the log/slog package. (Go 1.21 is expected to be released in August.)

What about separating the logger part to another PR and re-visiting after the Go 1.21 release?

[mirecl]

@KimMachineGun, now there is no way to manage logging outside the library and by default the log package is used. In the new function SetGoMemLimitWithOptions, I propose to give the user the opportunity to use
your logger (e.g. zap)

[KimMachineGun]

I think the printf style logger is not as customizable as slog.Logger. slog.Logger can even handle log level and logging style (in a structured way such as json, key-value style, etc) as well.

So I want to reserve the name WithLogger for slog.Logger and avoid adding new API (even in another name) likely to be deprecated soon (after Go 1.21).

Would slog.Logger not be sufficient to qualify your needs?

[mirecl]

@KimMachineGun, ✅
I propose to include these improvements in v0.3.0

[mirecl]

@KimMachineGun ,what do you think about it?

[KimMachineGun]

It seems like WithRatio and WithEnv work exclusively for each other.
What about not adding WithEnv and using the environment variable if WithRatio is not used?
(i.e. using the environment variable by default, and if the ratio is provided, using it instead.)

[KimMachineGun]

@mirecl
I apologize for the delayed review. I've been quite occupied these days 🥲.

[t-e-s-tweb]

Actually this is my question. Can I use the whole example code as it is? are these options chosen in some preference or do i have to only set one type of variable?

[KimMachineGun]

@t-e-s-tweb
Yes, this PR will not change(or remove) any public API exported before, so you can use the whole example code as it is.
And also, since I care about backward compatibility significantly, breaking change is unlikely to happen before the next major version.

[KimMachineGun]

@mirecl
Hi mirecl, Go 1.21 is finally released. Can we resume this pr?

[t-e-s-tweb]

quick question, if all the options are imported in go file, then how do they take priority over one another or should only one be used at a time? e.g using env, hardlimit by ram, by ratio or by cgroups? if all are added then which is applied? is there any way to check the currently applied limit?

[KimMachineGun]

@t-e-s-tweb
If I understand your question correctly, since the ratio and the provider are different concepts in automemlimit, basically no priority is there.
And you can check the current value of GOMEMLIMIT through debug.SetMemoryLimit(-1).

Below is a simplified version of the automemlimit process.

1. Get the ratio that specifies the portion of memory that will be used as GOMEMLIMIT.

• The default ratio is 0.9.
• You can configure it with SetGoMemLimitWithOptions + WithRatio.
• If you use SetGoMemLimitWithEnv or SetGoMemLimitWithOptions + WithEnv, you can overwrite the ratio at the application initialization time with the environment variable.

2. Get the total memory size from the provider.

• The default provider is FromCgroup. (support all cgroups versions)
• You can configure it with SetGoMemLimitWithOptions + WithProvider.

3. Apply the memory limit (total memory size * ratio).

[KimMachineGun]

I forked it to a new PR for the fast follow-up for Go 1.21.
Thank you again, @mirecl!

[t-e-s-tweb]

while using

func init() {
	// Configure memory limit with options
	memlimit.SetGoMemLimitWithOptions(
		memlimit.WithEnv(),          // Configure memory limit from environment variable
		memlimit.WithRatio(0.9),     // Set the memory limit ratio
		memlimit.WithProvider(memlimit.FromCgroupV2), // Use the FromCgroupV2 provider
	)

	// And so on...
}

i get

./main.go:13:11: undefined: memlimit.SetGoMemLimitWithOpts
./main.go:14:12: undefined: memlimit.WithEnv
./main.go:15:12: undefined: memlimit.WithRatio
./main.go:16:12: undefined: memlimit.WithProvider

[mirecl]

@KimMachineGun, most likely need a new release (tag).

[KimMachineGun]

@mirecl
This change will be released after a few days of testing.
I'll let you know when it is released.

[KimMachineGun]

@mirecl
This change was released as v0.3.0!