go-ionice

OS independent ionice for Golang

Introduction

This repository provides a Golang package for setting process IO priority (like ionice does on Linux) in an OS independent way. Currently Linux, MacOS and Windows are supported.

Example

package main 

import (
    "fmt"
    
    "github.com/secDre4mer/go-ionice"
)

func main() {
	niceness, _ := ionice.GetIoPriority()
	fmt.Println("IO priority is:", niceness)

	ionice.SetIoPriority(ionice.Low)
	fmt.Println("Changed IO priority to low!")
}

Error handling is omitted for brevity.

Handling of OS specific details

Some OS (e.g. Linux) offer a more detailed IO priority interface, whereas others (e.g. MacOS) provide only 3 levels that can be set. To abstract between these points of view, this package defines 5 niceness values (VeryLow to VeryHigh).

These niceness values are mapped to the OS specific values in some way: SetIoPriority is always valid with any niceness value, but some OS implementations might map High and VeryHigh to the same underlying value. Some OS specific values may also be mapped to the same Niceness despite being different.

Therefore, there is no guarantee that GetIoPriority returns the same value that was previously set with SetIoPriority, and there is also no guarantee that calling SetIoPriority with the return value of GetIoPriority is a no-op. This is typically true for the default values, but no promises beyond this are made.