diskusage

Documentation

Overview

Package diskusage calculates IO usage the of block devices. Usage is calculated by taking the difference between tow snapshots of IO statistics of block devices, /proc/diskstats. The time elapsed between the two snapshots is stored in the TimeDelta field. Instead of returning a Go struct, it returns JSON serialized bytes. A function to deserialize the JSON serialized bytes into a struct.DiskUsage struct is provided.

Note: the package name is diskusage and not the final element of the import path (json).

Index

• func Deserialize(p []byte) (*structs.DiskUsage, error)
• func Get() (p []byte, err error)
• func Marshal(u *structs.DiskUsage) ([]byte, error)
• func NewTicker(d time.Duration) (joe.Tocker, error)
• func Serialize(u *structs.DiskUsage) (p []byte, err error)
• func Unmarshal(p []byte) (*structs.DiskUsage, error)
• type Profiler
  • func NewProfiler() (prof *Profiler, err error)
  • func (prof *Profiler) Get() (p []byte, err error)
  • func (prof *Profiler) Marshal(u *structs.DiskUsage) ([]byte, error)
  • func (prof *Profiler) Serialize(u *structs.DiskUsage) ([]byte, error)
• type Ticker
  • func (t *Ticker) Close()
  • func (t *Ticker) Run()

Functions

func Deserialize

func Deserialize(p []byte) (*structs.DiskUsage, error)

Deserialize takes some JSON serialized bytes and unmarshals them as structs.DiskUsage.

func Get

func Get() (p []byte, err error)

Get returns the current IO usage of the block devices as JSON serialized bytes using the package's global Profiler. The Profiler is instantiated lazily. If the profiler doesn't already exist, the first utilization information will not be useful due to minimal time elapsing between the initial and second snapshots used for utilization calculations; the results of the first call should be discarded.

func Marshal

func Marshal(u *structs.DiskUsage) ([]byte, error)

Marshal is an alias for Serialize using the package global Profiler.

func NewTicker

func NewTicker(d time.Duration) (joe.Tocker, error)

NewTicker returns a new Ticker containing a Data channel that delivers the data at intervals and an error channel that delivers any errors encountered. Stop the ticker to signal the ticker to stop running. Stopping the ticker does not close the Data channel; call Close to close both the ticker and the data channel.

func Serialize

func Serialize(u *structs.DiskUsage) (p []byte, err error)

Serialize IO usage of the block devices as JSON using the package's global Profiler.

func Unmarshal

func Unmarshal(p []byte) (*structs.DiskUsage, error)

Unmarshal is an alias for Deserialize.

Types

type Profiler

type Profiler struct {
	*usage.Profiler
}

Profiler is used to process IO usage of the block devices using JSON.

func NewProfiler

func NewProfiler() (prof *Profiler, err error)

Returns an initialized Profiler; ready to use. Upon creation, a /proc/diskstats snapshot is taken so that any Get() will return valid information.

func (*Profiler) Get

func (prof *Profiler) Get() (p []byte, err error)

Get returns the current IO usage of the block devices as JSON serialized bytes. Calculating usage requires two snapshots. This func gets the current snapshot of /proc/diskstats and calculates the difference between that and the prior snapshot. The current snapshot is stored for use as the prior snapshot on the next Get call. If ongoing usage information is desired, the Ticker should be used; it's better suited for ongoing usage information.

func (*Profiler) Marshal

func (prof *Profiler) Marshal(u *structs.DiskUsage) ([]byte, error)

Marshal is an alias for Serialize.

func (*Profiler) Serialize

func (prof *Profiler) Serialize(u *structs.DiskUsage) ([]byte, error)

Serialize IO usage of the block devices using JSON.

type Ticker

type Ticker struct {
	*joe.Ticker
	Data chan []byte
	*Profiler
}

Ticker delivers the system's IO usage of the block devices at intervals.

func (*Ticker) Close

func (t *Ticker) Close()

Close closes the ticker resources.

func (*Ticker) Run

func (t *Ticker) Run()

Run runs the ticker.