flow

README

go-flow-metrics

A simple library for tracking flow metrics.

A simple alternative to rcrowley's go-metrics that's a lot faster (and only does simple bandwidth metrics).

Table of Contents

• Install
• Contribute
• License

Install

make install

Contribute

PRs are welcome!

Small note: If editing the Readme, please conform to the standard-readme specification.

License

MIT © Protocol Labs

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The last gx published version of this module was: 0.2.0: QmQFXpvKpF34dK9HcE7k8Ksk8V4BwWYZtdEcjzu5aUgRVr

Documentation

Index

• Variables
• func SetClock(c clock.Clock)
• type Meter
  • func NewMeter() *Meter
  • func (m *Meter) Mark(count uint64)
  • func (m *Meter) Reset()
  • func (m *Meter) Snapshot() Snapshot
  • func (m *Meter) String() string
• type MeterRegistry
  • func (r *MeterRegistry) Clear()
  • func (r *MeterRegistry) FindIdle(since time.Time) []string
  • func (r *MeterRegistry) ForEach(iterFunc func(string, *Meter))
  • func (r *MeterRegistry) Get(name string) *Meter
  • func (r *MeterRegistry) Remove(name string)
  • func (r *MeterRegistry) TrimIdle(since time.Time) (trimmed int)
• type Snapshot
  • func (s Snapshot) String() string

Examples

• Meter

Variables

var IdleTime = 20 * time.Second

IdleTime the time that need to pass scince last update before we declare a metere idle

Functions

func SetClock

func SetClock(c clock.Clock)

SetClock sets a clock to use in the sweeper. This will probably only ever be useful for testing purposes.

Types

type Meter

type Meter struct {
	// contains filtered or unexported fields
}

Meter is a meter for monitoring a flow.

Example

meter := new(Meter)
t := time.NewTicker(100 * time.Millisecond)
for i := 0; i < 100; i++ {
	<-t.C
	meter.Mark(30)
}

// Get the current rate. This will be accurate *now* but not after we
// sleep (because we calculate it using EWMA).
rate := meter.Snapshot().Rate

// Sleep 2 seconds to allow the total to catch up. We snapshot every
// second so the total may not yet be accurate.
time.Sleep(2 * time.Second)

// Get the current total.
total := meter.Snapshot().Total

fmt.Printf("%d (%d/s)\n", total, roundTens(rate))

Output:

3000 (300/s)

func NewMeter

func NewMeter() *Meter

NewMeter returns a new Meter with the correct idle time.

While zero-value Meters can be used, their "last update" time will start at the program start instead of when the meter was created.

func (*Meter) Mark

func (m *Meter) Mark(count uint64)

Mark updates the total.

func (*Meter) Reset

func (m *Meter) Reset()

Reset sets accumulator, total and rate to zero.

func (*Meter) Snapshot

func (m *Meter) Snapshot() Snapshot

Snapshot gets a snapshot of the total and rate.

func (*Meter) String

func (m *Meter) String() string

type MeterRegistry

type MeterRegistry struct {
	// contains filtered or unexported fields
}

MeterRegistry is a registry for named meters.

func (*MeterRegistry) Clear

func (r *MeterRegistry) Clear()

Clear removes all meters from the registry.

func (*MeterRegistry) FindIdle

func (r *MeterRegistry) FindIdle(since time.Time) []string

FindIdle finds all meters that haven't been used since the given time.

func (*MeterRegistry) ForEach

func (r *MeterRegistry) ForEach(iterFunc func(string, *Meter))

ForEach calls the passed function for each registered meter.

func (*MeterRegistry) Get

func (r *MeterRegistry) Get(name string) *Meter

Get gets (or creates) a meter by name.

func (*MeterRegistry) Remove

func (r *MeterRegistry) Remove(name string)

Remove removes the named meter from the registry.

Note: The only reason to do this is to save a bit of memory. Unused meters don't consume any CPU (after they go idle).

func (*MeterRegistry) TrimIdle

func (r *MeterRegistry) TrimIdle(since time.Time) (trimmed int)

TrimIdle trims that haven't been updated since the given time. Returns the number of timers trimmed.

type Snapshot

type Snapshot struct {
	Rate       float64
	Total      uint64
	LastUpdate time.Time
}

Snapshot is a rate/total snapshot.

func (Snapshot) String

func (s Snapshot) String() string