metrics

package
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 Go to latest Published: Feb 28, 2025 License: Apache-2.0 Imports: 16 Imported by: 0

README

Task Metrics using Prometheus in Go

Table of Contents

Introduction

This project provides a comprehensive metrics collection and reporting framework integrated with Prometheus for Go applications.

Features

  • Different types of metrics collectors including Counter, Gauge, and Histogram.
  • Built-in Prometheus server.
  • Strong typing to prevent metrics misuse.
  • Error handling and logging integrated with Uber's Zap library.
  • Support for custom labels.
  • Thread-safe metric updates with read-write mutexes.
  • Auto-registering of metrics based on type.

Default Labels

Every metric reported by the framework automatically includes the following labels to provide more context about the application's environment:

  • app_name: Identifies the name of the application.
  • app_revision: Specifies the current revision of the application, typically a Git commit hash or a similar identifier.
  • app_version: Indicates the current version of the application.

These labels help in distinguishing metrics across different environments, versions, and revisions of the application. For example, a metric for request duration might look like this:

request_duration_ms{app_name="ledger-live",app_revision="main-9a60456",app_version="v0.8.3",method="GET",path="/addresses/{address}/transactions",status="200"} 435

This approach ensures that metrics data can be correlated with specific releases and deployments of the application, providing valuable insights during analysis and troubleshooting.

Code Structure

  • /metrics/collectors/: Contains the implementation of various metrics collectors (Counter, Gauge, Histogram).
  • /metrics/handler.go: Contains the MetricHandler interface and taskMetrics UpdateMetric, IncrementMetric, and DecrementMetric methods for updating metrics.
  • /metrics/prometheus.go: Defines the Prometheus server.
  • /metrics/register.go: Responsible for registering metrics with the Prometheus server.

Metrics Collectors

Counter
  • File: /metrics/collectors/counter.go
  • Methods: Update
  • Usage: Counters are cumulative metrics that can only increase.
Gauge
  • File: /metrics/collectors/gauge.go
  • Methods: Update, Inc, Dec
  • Usage: Gauges are metrics that can arbitrarily go up and down.
Histogram
  • File: /metrics/collectors/histogram.go
  • Methods: Update
  • Usage: Histograms count observations (like request durations or response sizes) and place them in configurable buckets.

Usage

Starting the Server
metricsServer := metrics.NewTaskMetrics("/metrics", "9090")
err := metricsServer.Start()
if err != nil {
    log.Fatal(err)
}
Registering Metrics
// Without labels
err = metricsServer.RegisterMetric("my_counter", "This is a counter metric", nil, &collectors.Counter{})

// With labels
err = metricsServer.RegisterMetric("my_counter_with_labels", "This is a counter metric with labels", []string{"label1", "label2"}, &collectors.Counter{})

// Register a gauge
err = metricsServer.RegisterMetric("my_gauge", "This is a gauge metric", nil, &collectors.Gauge{})
Updating Metrics
// Without labels
metricsServer.UpdateMetric("my_counter", 1)

// With labels
metricsServer.UpdateMetric("my_counter_with_labels", 1, "label1_value", "label2_value")

// Increment a gauge
metricsServer.IncrementMetric("my_gauge")

// Decrement a gauge
metricsServer.DecrementMetric("my_gauge")
Mocking Support

Use MockTaskMetrics for testing.

func TestMetrics(t *testing.T) {
    tm := &metrics.MockTaskMetrics{}
	  tm.On("RegisterMetric", "local_cache_cleanup_errors", mock.Anything, []string{"error_type"}, mock.Anything).Once().Return(nil)
    // Use tm in your tests
}

To generate mocks:

  • install: https://github.com/vektra/mockery
  • pull the repo with the correct version of the interface you want to mock
  • mockery --name TaskMetrics --dir ./pkg/metrics --output . --filename task_metrics_mock.go --structname MockTaskMetrics --inpackage
  • For usage in tests

Documentation

Index

Constants

View Source 
const (
	APPNameLabel = "app_name"
)

Variables

This section is empty.

Functions

func RegisterSystemMetrics added in v0.15.7 

func RegisterSystemMetrics(metricsServer TaskMetrics) []error

func UpdateSystemMetrics added in v0.15.7 

func UpdateSystemMetrics(metricsServer TaskMetrics, updateInterval time.Duration)

Types

type IncrementDecrementHandler added in v0.6.0 

type IncrementDecrementHandler interface {
	MetricHandler
	Inc(collector prometheus.Collector, labels ...string) error
	Dec(collector prometheus.Collector, labels ...string) error
}

type MetricDetail added in v0.4.0 

type MetricDetail struct {
	Collector prometheus.Collector
	Handler   MetricHandler
}

type MetricHandler added in v0.4.0 

type MetricHandler interface {
	Update(collector prometheus.Collector, value float64, labels ...string) error
	Type() string
}

type MockTaskMetrics added in v0.17.0 

type MockTaskMetrics struct {
	mock.Mock
}

MockTaskMetrics is an autogenerated mock type for the TaskMetrics type

func NewMockTaskMetrics added in v0.17.0 

func NewMockTaskMetrics(t mockConstructorTestingTNewMockTaskMetrics) *MockTaskMetrics

NewMockTaskMetrics creates a new instance of MockTaskMetrics. It also registers a testing interface on the mock and a cleanup function to assert the mocks expectations.

func (*MockTaskMetrics) AppName added in v0.17.0 

func (_m *MockTaskMetrics) AppName() string

AppName provides a mock function with given fields:

func (*MockTaskMetrics) DecrementMetric added in v0.17.0 

func (_m *MockTaskMetrics) DecrementMetric(name string, labels ...string) error

DecrementMetric provides a mock function with given fields: name, labels

func (*MockTaskMetrics) IncrementMetric added in v0.17.0 

func (_m *MockTaskMetrics) IncrementMetric(name string, labels ...string) error

IncrementMetric provides a mock function with given fields: name, labels

func (*MockTaskMetrics) Name added in v0.17.0 

func (_m *MockTaskMetrics) Name() string

Name provides a mock function with given fields:

func (*MockTaskMetrics) RegisterMetric added in v0.17.0 

func (_m *MockTaskMetrics) RegisterMetric(name string, help string, labels []string, handler MetricHandler) error

RegisterMetric provides a mock function with given fields: name, help, labels, handler

func (*MockTaskMetrics) Start added in v0.17.0 

func (_m *MockTaskMetrics) Start() error

Start provides a mock function with given fields:

func (*MockTaskMetrics) Stop added in v0.17.0 

func (_m *MockTaskMetrics) Stop() error

Stop provides a mock function with given fields:

func (*MockTaskMetrics) UpdateMetric added in v0.17.0 

func (_m *MockTaskMetrics) UpdateMetric(name string, value float64, labels ...string) error

UpdateMetric provides a mock function with given fields: name, value, labels

type NoopMetrics added in v0.20.0 

type NoopMetrics struct{}

NoopMetrics provides an implementation of the TaskMetrics that produces no telemetry and minimizes used computation resources.

func (NoopMetrics) AppName added in v0.20.0 

func (n NoopMetrics) AppName() string

func (NoopMetrics) DecrementMetric added in v0.20.0 

func (n NoopMetrics) DecrementMetric(_ string, _ ...string) error

func (NoopMetrics) IncrementMetric added in v0.20.0 

func (n NoopMetrics) IncrementMetric(_ string, _ ...string) error

func (NoopMetrics) Name added in v0.20.0 

func (n NoopMetrics) Name() string

func (NoopMetrics) RegisterMetric added in v0.20.0 

func (n NoopMetrics) RegisterMetric(_, _ string, _ []string, _ MetricHandler) error

func (NoopMetrics) Start added in v0.20.0 

func (n NoopMetrics) Start() error

func (NoopMetrics) Stop added in v0.20.0 

func (n NoopMetrics) Stop() error

func (NoopMetrics) UpdateMetric added in v0.20.0 

func (n NoopMetrics) UpdateMetric(_ string, _ float64, _ ...string) error

type TaskMetrics added in v0.3.0 

type TaskMetrics interface {
	Start() error
	RegisterMetric(name string, help string, labels []string, handler MetricHandler) error
	UpdateMetric(name string, value float64, labels ...string) error
	IncrementMetric(name string, labels ...string) error
	DecrementMetric(name string, labels ...string) error
	Name() string
	AppName() string
	Stop() error
}

func NewNoopMetrics added in v0.20.0 

func NewNoopMetrics() TaskMetrics

NewNoopMetrics creates and returns a new instance that implements the TaskMetrics interface without generating any metrics or telemetry.

func NewTaskMetrics added in v0.3.0 

func NewTaskMetrics(path, port, appName string) TaskMetrics

Source Files

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