fakemetrics

README

FakeMetrics

FakeMetrics is a Go package designed for generating fake metrics that can be integrated with Prometheus or Victoria Metrics. This package is ideal for testing and demo purposes, providing a simple way to simulate metric data without needing a live system.

Features

• Fake Counters: Automatically increments counters with random values.
• Fake Gauges: Generates gauges that return random float values.
• Fake Histograms: Updates histograms with random values.
• Customizable: Configure the number of each metric type, update intervals, prefixes, and static labels.
• Update Metrics Toggle: Choose whether to periodically update generated metrics via the UpdateMetrics configuration flag.

Installation

To use FakeMetrics in your Go project, install it using go get:

bash

go get github.com/wabel-v0/fakemetrics

Then import it in your code:

go

import (
    "github.com/wabel-v0/fakemetrics"
)

Usage

Below is a basic example of how to use FakeMetrics:

go

package fakemetrics

  

 import (

 "net/http"

 "time"

  

 "github.com/VictoriaMetrics/metrics"

"github.com/wabel-v0/fakemetrics"

 )

  

 func main() {

//  Configure metrics generation

cfg := fakemetrics.Config{

 MetricPrefix: "app_",

 NumCounters: 5,

 NumGauges: 3,

 NumHistograms: 2,

 UpdateInterval: 2 * time.Second,

 Labels: map[string]string{

 "environment": "production",

 },
// Set UpdateMetrics to true to periodically update generated metrics.
// Set to false if you want to only register metrics  and not update them.
UpdateMetrics: true,

 }

  

// Create and start generator

 gen := fakemetrics.New(cfg)

 gen.Start()

 defer gen.Stop()

  

 // Set up metrics endpoint

 http.HandleFunc("/metrics", func(w http.ResponseWriter, req *http.Request) {

 metrics.WritePrometheus(w, true)

 })

  

 // Start server

 http.ListenAndServe(":8080", nil)

 }

Configuration

The Config struct allows you to customize the behavior of the metrics generator:

go

type Config struct {
    MetricPrefix   string            // Prefix added to each metric name (default: "fake_")
    NumCounters    int               // Number of counters to create (default: 10)
    NumGauges      int               // Number of gauges to create (default: 10)
    NumHistograms  int               // Number of histograms to create (default: 10)
    UpdateInterval time.Duration     // Interval for updating metric values (default: 2s)
    Labels         map[string]string // A set of labels to be appended to each metric (default: {"environment": "lazy"})
	UpdateMetrics  bool              // If true, periodically update generated metrics (default: false)

}

How It Works

1. Metric Creation: Upon starting, the generator creates the specified number of counters, gauges, and histograms. Each metric name is prefixed with MetricPrefix, and additional labels are appended in Prometheus style (e.g., key="value").

2. Metric Updates: If enabled by the UpdateMetrics flag, a goroutine runs on a ticker based on the UpdateInterval. Each tick performs the following:

• Counters are incremented by a random value.
• Gauges provide a new random float value (via a dynamic function).
• Histograms are updated with new random float values.

1. Graceful Stop: The generator can be stopped gracefully, ensuring that the background goroutine exits cleanly.

Dependencies

This project uses the following libraries:

• VictoriaMetrics/metrics: For metric registration and manipulation.

Feel free to contribute or open issues if you have any questions. Enjoy testing!

Documentation

Index

• type Config
• type Generator
  • func New(cfg Config) *Generator
  • func (g *Generator) Start()
  • func (g *Generator) Stop()

Types

type Config

type Config struct {
	MetricPrefix   string
	NumCounters    int
	NumGauges      int
	NumHistograms  int
	UpdateInterval time.Duration
	Labels         map[string]string
	UpdateMetrics  bool
}

Config defines the fake metrics generation parameters

type Generator

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

Generator creates and manages fake metrics

func New

func New(cfg Config) *Generator

New creates a metrics generator with default values

func (*Generator) Start

func (g *Generator) Start()

Start begins updating metric values

func (*Generator) Stop

func (g *Generator) Stop()

Stop halts metric updates