constraints

Documentation

Overview

package constraints contains methods for decoding a compact CPU and Memory constraints format. We specify the "constraints" format as the following:

<cpushare>:<memory limit>

CPUShare can be any number between 2 and 1024. For more details on how the --cpu-shares flag works in Docker/cgroups, see https://docs.docker.com/reference/run/#cpu-share-constraint

Memory limit can contain a number and optionally the units. The following are all equivalent:

6GB
6144MB
6291456KB

Index

• Constants
• Variables
• type CPUShare
  • func NewCPUShare(i int) (CPUShare, error)
  • func ParseCPUShare(s string) (CPUShare, error)
• type Constraints
  • func Parse(s string) (Constraints, error)
• type Memory
  • func ParseMemory(s string) (Memory, error)
  • func (m Memory) String() string
• type Nproc
  • func ParseNproc(s string) (Nproc, error)

Constants

const ConstraintsSeparator = ":"

ConstraintsSeparator separates the individual resource constraints

Variables

var (
	ErrInvalidCPUShare   = errors.New("CPUShare must be a value between 2 and 1024")
	ErrInvalidMemory     = errors.New("invalid memory format")
	ErrInvalidConstraint = errors.New("invalid constraints format")
)

Types

type CPUShare

type CPUShare int

CPUShare represents a CPUShare.

func NewCPUShare

func NewCPUShare(i int) (CPUShare, error)

NewCPUShare casts i to a CPUShare and ensures its validity.

func ParseCPUShare

func ParseCPUShare(s string) (CPUShare, error)

type Constraints

type Constraints struct {
	CPUShare
	Memory
	Nproc
}

Constraints is a composition of CPUShares, Memory and Nproc constraints.

func Parse

func Parse(s string) (Constraints, error)

type Memory

type Memory uint

Memory represents a memory limit.

func ParseMemory

func ParseMemory(s string) (Memory, error)

ParseMemory parses a string in memory format and returns the amount of memory in bytes.

func (Memory) String

func (m Memory) String() string

String returns the string representation of Memory, using the following algorithm:

* If the memory is less than 1 KB, it will return "x". * If the memory is less than 1 MB, it will return "xKB". * If the memory is less than 1 GB, it will return "xMB". * etc

type Nproc

type Nproc uint

func ParseNproc

func ParseNproc(s string) (Nproc, error)