aws-embedded-metrics-golang

README

aws-embedded-metrics-golang

Go implementation of AWS CloudWatch Embedded Metric Format

It's aim is to simplify reporting metrics to CloudWatch:

• using EMF avoids additional HTTP API calls to CloudWatch as metrics are logged in JSON format to stdout
• no need for additional dependencies in your services (or mocks in tests) to report metrics from inside your code
• built in support for default dimensions and properties for Lambda functions
• TODO support for default dimensions and properties for EC2 (please send pull requests)

Supports namespaces, setting dimensions and properties as well as different contexts (at least partially).

Usage:

emf.New().Namespace("mtg").Metric("totalWins", 1500).Log()

emf.New().Dimension("colour", "red").
    MetricAs("gameLength", 2, emf.Seconds).Log()

emf.New().DimensionSet(
        emf.NewDimension("format", "edh"),
        emf.NewDimension("commander", "Muldrotha")).
    MetricAs("wins", 1499, emf.Count).Log()

You may also use the lib together with defer.

m := emf.New() // sets up whatever you fancy here
defer m.Log()

// any reporting metrics calls

Customizing the logger:

emf.New(
    emf.WithWriter(os.Stderr), // Log to stderr.
    emf.WithTimestamp(time.Now().Add(-time.Hour)), // Record past metrics.
    emf.WithoutDimensions(), // Do not include useful Lambda related dimensions.
)

Functions for reporting metrics:

func Metric(name string, value int)
func Metrics(m map[string]int)
func MetricAs(name string, value int, unit MetricUnit)
func MetricsAs(m map[string]int, unit MetricUnit)

func MetricFloat(name string, value float64)
func MetricsFloat(m map[string]float64)
func MetricFloatAs(name string, value float64, unit MetricUnit)
func MetricsFloatAs(m map[string]float64, unit MetricUnit)

Functions for setting up dimensions:

func Dimension(key, value string)
func DimensionSet(dimensions ...Dimension) // use `func NewDimension` for creating one