meter

package module
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 Go to latest Published: Jun 19, 2020 License: Apache-2.0 Imports: 13 Imported by: 0

README

gometer

Metrics gathering library.

Installation

You can download the code via the usual go utilities:

go get github.com/datacratic/gometer/meter

To build the code and run the test suite along with several static analysis tools, use the provided Makefile:

make test

Note that the usual go utilities will work just fine but we require that all commits pass the full suite of tests and static analysis tools.

Documentation

Documentation is available at godoc and usage examples are available in this test suite.

License

The source code is available under the Apache License. See the LICENSE file for more details.

Documentation

Overview

Copyright (c) 2014 Datacratic. All rights reserved.

Index

Constants

View Source 
const DefaultHistogramSize = 1000

DefaultHistogramSize is used if Size is not set in Histogram.

Variables

View Source 
var (
	// CarbonDialTimeout is the timeout value when dialing the remote carbon
	// host.
	CarbonDialTimeout = 1 * time.Second

	// CarbonMaxConnDelay is the maximum value of the exponential backoff scheme
	// when reconecting to a carbon host.
	CarbonMaxConnDelay = 1 * time.Minute
)

Functions

func Add 

func Add(key string, meter Meter) bool

Add associates the given meter with the given key and begins to periodically poll the meter.

func Handle 

func Handle(handler Handler)

Handle adds the given handler to the list of handlers to be executed after polling the meters.

func Join 

func Join(items ...string) string

Join concatenates the given items with a '.' character where necessary.

func Load 

func Load(obj interface{}, prefix string)

Load crawls the given object to register and instantiate any pointer to meters that it finds. The meter key will be derived from the name of the field that contains the meter and will be prefixed by the given prefix string. If a structure is encoutered then it will be recursively crawled with the name of the field appended to the given prefix.

func Poll 

func Poll(prefix string, rate time.Duration)

Poll starts a background goroutine which will periodically poll the registered meters at the given rate and prepend all the polled keys with the given prefix.

func Remove 

func Remove(key string)

Remove removes any meters associated with the key which will no longer be polled.

func Unload 

func Unload(obj interface{}, prefix string)

Unload crawls the given object and deregisters any pointer to meters that it finds. See Load for more details about the crawling and naming behaviour.

Types

type CarbonHandler 

type CarbonHandler struct {

	// URLs contains the list of carbon hosts to connect to.
	URLs []string
	// contains filtered or unexported fields
}

CarbonHandler forwards a set of recorded meter values to multiple carbon hosts. Any values received while the connection to the carbon host is unavailable are dropped.

func NewCarbonHandler 

func NewCarbonHandler(URL string) *CarbonHandler

NewCarbonHandler instantiates a new CarbonHandler which will log to the given URL.

func (*CarbonHandler) HandleMeters 

func (carbon *CarbonHandler) HandleMeters(values map[string]float64)

HandleMeters forwards the given values to all the carbon host with a valid connection.

func (*CarbonHandler) Init 

func (carbon *CarbonHandler) Init()

Init can be optionally used to initialize the object. Note that the handler will lazily initialize itself as needed.

type Counter 

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

Counter counts the number of occurence of an event. Is also completely go-routine safe.

func GetCounter 

func GetCounter(prefix string) *Counter

GetCounter returns the counter registered with the given key or creates a new one and registers it.

func (*Counter) Count 

func (counter *Counter) Count(count uint64)

Count adds the given value to the counter.

func (*Counter) Hit 

func (counter *Counter) Hit()

Hit adds 1 to the counter.

func (*Counter) ReadMeter 

func (counter *Counter) ReadMeter(delta time.Duration) map[string]float64

ReadMeter returns the current count and resets the counter's value to 0. The returned value is normalized using the given delta to ensure that the value always represents a per second value.

type Gauge 

type Gauge struct {

	// Value contains the initial value of the gauge. Should not be read or
	// written after construction.
	Value float64
	// contains filtered or unexported fields
}

Gauge reports a recorded value until a new value is recorded. This can be useful to record the result of rare or periodic events by ensuring that the results are always available and hard to miss.

func GetGauge 

func GetGauge(prefix string) *Gauge

GetGauge returns the gauge registered with the given key or creates a new one and registers.

func (*Gauge) Change 

func (gauge *Gauge) Change(value float64)

Change changes the recorded value.

func (*Gauge) ChangeDuration 

func (gauge *Gauge) ChangeDuration(duration time.Duration)

ChangeDuration similar to Change but with a time.Duration value.

func (*Gauge) ChangeSince 

func (gauge *Gauge) ChangeSince(t0 time.Time)

ChangeSince records a duration elapsed since the given time.

func (*Gauge) ReadMeter 

func (gauge *Gauge) ReadMeter(_ time.Duration) map[string]float64

ReadMeter returns the currently set value if not equal to 0.

type Handler 

type Handler interface {
	HandleMeters(map[string]float64)
}

Handler is used to periodically process the aggregated values of multiple meters.

type HandlerFunc 

type HandlerFunc func(map[string]float64)

HandlerFunc is used to wrap a function as a Handler interface.

func (HandlerFunc) HandleMeters 

func (fn HandlerFunc) HandleMeters(values map[string]float64)

HandleMeters forwards the call to the wrapped function.

type Histogram 

type Histogram struct {

	// Size is maximum number of elements that the histogram can hold. Above
	// this amount, new values are sampled.
	Size int

	// SamplingSeed is the initial seed for the RNG used during sampling.
	SamplingSeed int64
	// contains filtered or unexported fields
}

Histogram aggregates metrics over a histogram of values.

Record will add up to a maximum of Size elements after which new elements will be randomly sampled with a probability that depends on the number of elements recorded. This schemes ensures that a histogram has a constant memory footprint and doesn't need to allocate for calls to Record.

ReadMeter will compute percentiles over the sampled histogram and the min and max value seen over the entire histogram.

Histogram is completely go-routine safe.

func GetHistogram 

func GetHistogram(prefix string) *Histogram

GetHistogram returns the histogram registered with the given key or creates a new one and registers it.

func (*Histogram) ReadMeter 

func (dist *Histogram) ReadMeter(_ time.Duration) map[string]float64

ReadMeter computes various statistic over the sampled histogram (50th, 90th and 99th percentile) and the count, min and max over the entire histogram. All recorded elements are then discarded from the histogram.

func (*Histogram) Record 

func (dist *Histogram) Record(value float64)

Record adds the given value to the histogram with a probability based on the number of elements recorded since the last call to ReadMeter.

func (*Histogram) RecordDuration 

func (dist *Histogram) RecordDuration(duration time.Duration)

RecordDuration similar to Record but with time.Duration values.

func (*Histogram) RecordSince 

func (dist *Histogram) RecordSince(t0 time.Time)

RecordSince records a duration elapsed since the given time.

type Meter 

type Meter interface {
	ReadMeter(time.Duration) map[string]float64
}

Meter represents a meter used to record various metrics which will be read periodically. The time.Duration parameter is used to normalize the values read by the meter so that they represent a per second values.

func Get 

func Get(key string) Meter

Get returns the meter associated with the given key or nil if no such meter exists.

func GetOrAdd 

func GetOrAdd(key string, meter Meter) Meter

GetOrAdd registers the given meter with the given key if it's not already registered or returns the meter associated with the given key.

type MultiCounter 

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

MultiCounter associates Counter objects to keys which can be selected when recording. Is completely go-routine safe.

func GetMultiCounter 

func GetMultiCounter(prefix string) *MultiCounter

GetMultiCounter returns the counter registered with the given key or creates a new one and registers it.

func (*MultiCounter) Count 

func (multi *MultiCounter) Count(key string, count uint64)

Count calls Count on the counter associated with the given key. New Keys are lazily created as required.

func (*MultiCounter) Hit 

func (multi *MultiCounter) Hit(key string)

Hit calls Hit on the counter associated with the given key. New Keys are lazily created as required.

func (*MultiCounter) ReadMeter 

func (multi *MultiCounter) ReadMeter(delta time.Duration) map[string]float64

ReadMeter calls ReadMeter on all underlying counters where all the keys are prefixed by the key name used in the calls to Record.

type MultiGauge 

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

MultiGauge associates Gauge objects to keys which can be selected when recording. Is completely go-routine safe.

func GetMultiGauge 

func GetMultiGauge(prefix string) *MultiGauge

GetMultiGauge returns the gauge registered with the given key or creates a new one and registers it.

func (*MultiGauge) Change 

func (multi *MultiGauge) Change(key string, value float64)

Change records the given value with the gauge associated with the given key. New Keys are lazily created as required.

func (*MultiGauge) ChangeDuration 

func (multi *MultiGauge) ChangeDuration(key string, duration time.Duration)

ChangeDuration similar to Change but with a time.Duration value.

func (*MultiGauge) ChangeSince 

func (multi *MultiGauge) ChangeSince(key string, t0 time.Time)

ChangeSince records a duration elapsed since the given time with the given key.

func (*MultiGauge) ReadMeter 

func (multi *MultiGauge) ReadMeter(delta time.Duration) map[string]float64

ReadMeter calls ReadMeter on all underlying gauges where all the keys are prefixed by the key name used in the calls to Record.

type MultiHistogram 

type MultiHistogram struct {

	// Size is used to initialize the Size member of the underlying Histogram
	// objects.
	Size int

	// SamplingSeed is used to initialize the SamplingSeed member of underlying
	// Histogram objects.
	SamplingSeed int64
	// contains filtered or unexported fields
}

MultiHistogram associates Histogram objects to keys which can be selected when recording. Is completely go-routine safe.

func GetMultiHistogram 

func GetMultiHistogram(prefix string) *MultiHistogram

GetMultiHistogram returns the histogram registered with the given key or creates a new one and registers it.

func (*MultiHistogram) ReadMeter 

func (multi *MultiHistogram) ReadMeter(delta time.Duration) map[string]float64

ReadMeter calls ReadMeter on all the underlying histograms where all the keys are prefixed by the key name used in the calls to Record.

func (*MultiHistogram) Record 

func (multi *MultiHistogram) Record(key string, value float64)

Record adds the given value to the histogram associated with the given key. New keys are lazily created as required.

func (*MultiHistogram) RecordDuration 

func (multi *MultiHistogram) RecordDuration(key string, value time.Duration)

RecordDuration similar to Record but with time.Duration values.

func (*MultiHistogram) RecordSince 

func (multi *MultiHistogram) RecordSince(key string, t0 time.Time)

RecordSince records a duration elapsed since the given time for the given key.

type Pattern 

type Pattern []string

func NewPattern 

func NewPattern(pattern string) Pattern

func (Pattern) Match 

func (pattern Pattern) Match(key string) (result []string, ok bool)

func (Pattern) String 

func (pattern Pattern) String() string

type Poller 

type Poller struct {

	// Meters contains the initial list of meters to be polled. Should not be
	// read or modified after calling Init.
	Meters map[string]Meter

	// Handlers contains the initial list of handlers. Should not be read or
	// modified after calling init.
	Handlers []Handler
	// contains filtered or unexported fields
}

Poller periodically calls ReadMeter on all the meters registered via the Add function and forwards the aggregated values to all the configured handlers. 

var DefaultPoller Poller

DefaultPoller is the Poller object used by the global Add, Remove and Handle functions.

func (*Poller) Add 

func (poller *Poller) Add(key string, meter Meter) bool

Add registers the given meter which will be polled periodically and associates it with the given key. If the key is already registered then the old meter will be replaced by the given meter.

func (*Poller) Get 

func (poller *Poller) Get(key string) Meter

Get returns the meter associated with the given key or nil if no such meter exists.

func (*Poller) Handle 

func (poller *Poller) Handle(handler Handler)

Handle adds the given handler to the list of handler to execute.

func (*Poller) Poll 

func (poller *Poller) Poll(prefix string, rate time.Duration)

Poll starts a background goroutine which will periodically poll the registered meters at the given rate and prepend all the polled keys with the given prefix.

func (*Poller) Remove 

func (poller *Poller) Remove(key string)

Remove unregisters the given meter which will no longer be polled periodically.

type State 

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

State reports the value 1.0 for a given state until a new state is recorded. This can be useful to record infrequent changes in program state.

func GetState 

func GetState(prefix string) *State

GetState returns the state registered with the given key or creates a new one and registers it.

func (*State) Change 

func (state *State) Change(value string)

Change changes the recorded state. An empty string will not output any values.

func (*State) ReadMeter 

func (state *State) ReadMeter(delta time.Duration) map[string]float64

ReadMeter returns the currently set state with a value of 1.0 or nothing if the state is an empty string.

func (*State) Reset 

func (state *State) Reset()

Reset disables any values outputed by this state.

type TranslationHandler 

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

func NewTranslationHandler 

func NewTranslationHandler(patterns map[string]string) *TranslationHandler

func (*TranslationHandler) HandleMeters 

func (handler *TranslationHandler) HandleMeters(values map[string]float64)

Source Files

View all Source files

Directories

Path Synopsis
meter module

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