test

Documentation

Overview

Package test for testing code instrumented with the metric and stats packages.

Index

• type Exporter
  • func NewExporter(metricReader *metricexport.Reader) *Exporter
  • func (e *Exporter) ExportMetrics(ctx context.Context, data []*metricdata.Metric) error
  • func (e *Exporter) GetPoint(metricName string, labels map[string]string) (metricdata.Point, bool)
  • func (e *Exporter) ReadAndExport()
  • func (e *Exporter) String() string

Examples

• Exporter (Metric)
• Exporter (Stats)

Types

type Exporter

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

Exporter keeps exported metric data in memory to aid in testing the instrumentation.

Metrics can be retrieved with `GetPoint()`. In order to deterministically retrieve the most recent values, you must first invoke `ReadAndExport()`.

Example (Metric)

metricReader := metricexport.NewReader()
metrics := NewExporter(metricReader)
m := derivedMetric{}
r := metric.NewRegistry()
g, _ := r.AddInt64DerivedCumulative("derived", metric.WithLabelKeys(myTag.Name()))
g.UpsertEntry(m.ToInt64, metricdata.NewLabelValue("l1"))
for i := 1; i <= 3; i++ {
	// The code under test begins here.
	m.i = int64(i)
	// The code under test ends here.

	metrics.ExportMetrics(context.Background(), r.Read())
	metricValue := getCounter(metrics, "derived", newMetricKey("l1"))
	fmt.Println(metricValue)
}

Output:

1
2
3

Example (Stats)

metricReader := metricexport.NewReader()
metrics := NewExporter(metricReader)
metrics.ReadAndExport()
metricBase := getCounter(metrics, myMetric.Name(), newMetricKey("label1"))

for i := 1; i <= 3; i++ {
	// The code under test begins here.
	stats.RecordWithTags(context.Background(),
		[]tag.Mutator{tag.Upsert(myTag, "label1")},
		myMetric.M(int64(i)))
	// The code under test ends here.

	metrics.ReadAndExport()
	metricValue := getCounter(metrics, myMetric.Name(), newMetricKey("label1"))
	fmt.Printf("increased by %d\n", metricValue-metricBase)
}

Output:

increased by 1
increased by 3
increased by 6

func NewExporter

func NewExporter(metricReader *metricexport.Reader) *Exporter

NewExporter returns a new exporter.

func (*Exporter) ExportMetrics

func (e *Exporter) ExportMetrics(ctx context.Context, data []*metricdata.Metric) error

ExportMetrics records the view data.

func (*Exporter) GetPoint

func (e *Exporter) GetPoint(metricName string, labels map[string]string) (metricdata.Point, bool)

GetPoint returns the latest point for the time series identified by the given labels.

func (*Exporter) ReadAndExport

func (e *Exporter) ReadAndExport()

ReadAndExport reads the current values for all metrics and makes them available to this exporter.

func (*Exporter) String

func (e *Exporter) String() string

String defines the “native” format for the exporter.