github.com/facebookincubator/go-belt@v0.0.0-20230703220935-39cd348f1a38/tool/experimental/metrics/implementation/prometheus/metrics_test.go

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// Copyright (c) Facebook, Inc. and its affiliates.
//
// This source code is licensed under the MIT license found in the
// LICENSE file in the root directory of this source tree.

package prometheus

import (
	"fmt"
	"sort"
	"strings"
	"testing"

	"github.com/facebookincubator/go-belt/pkg/field"
	"github.com/facebookincubator/go-belt/tool/experimental/metrics"
	metricstester "github.com/facebookincubator/go-belt/tool/experimental/metrics/tests"
	"github.com/facebookincubator/go-belt/tool/experimental/metrics/types"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func contextFields(fields map[string]interface{}) *field.FieldsChain {
	var cFields *field.FieldsChain
	for k, v := range fields {
		cFields = cFields.WithField(k, v, metrics.AllowInMetrics)
	}
	return cFields
}

func TestMetrics(t *testing.T) {
	for name, registerer := range map[string]*prometheus.Registry{
		"WithRegisterer":    prometheus.NewRegistry(),
		"WithoutRegisterer": nil,
	} {
		t.Run(name, func(t *testing.T) {
			metricstester.TestMetrics(t, func() types.Metrics {
				cFields := contextFields(map[string]interface{}{"testField": "", "anotherField": ""})

				// Current implementation resets metrics if new label appears,
				// thus some unit-tests fails (and the should). Specifically
				// for prometheus we decided to tolerate this problem, therefore
				// adding hacks to prevent a wrong values: pre-register metrics
				// with all the labels beforehand.
				m := New(registerer)
				m.WithContextFields(cFields, -1).(types.Metrics).Count("WithResetFields")
				m.WithContextFields(cFields, -1).(types.Metrics).Gauge("WithResetFields")
				m.WithContextFields(cFields, -1).(types.Metrics).IntGauge("WithResetFields")

				return m
			})
		})
	}
}

func TestMetricsList(t *testing.T) {
	m := New(nil)
	c0 := m.WithContextFields(contextFields(map[string]interface{}{"testField": "", "anotherField": ""}), -1).(types.Metrics).Count("test")
	g0 := m.WithContextFields(contextFields(map[string]interface{}{"testField": "", "anotherField": ""}), -1).(types.Metrics).Gauge("test")
	i0 := m.WithContextFields(contextFields(map[string]interface{}{"testField": "", "anotherField": ""}), -1).(types.Metrics).IntGauge("test")
	c1 := m.WithContextFields(contextFields(map[string]interface{}{"testField": "a", "anotherField": ""}), -1).(types.Metrics).Count("test")
	g1 := m.WithContextFields(contextFields(map[string]interface{}{"testField": "b", "anotherField": ""}), -1).(types.Metrics).Gauge("test")
	i1 := m.WithContextFields(contextFields(map[string]interface{}{"testField": "c", "anotherField": ""}), -1).(types.Metrics).IntGauge("test")

	list := m.List()
	require.Len(t, list, 3)
	for _, c := range list {
		ch := make(chan prometheus.Metric)
		go func() {
			c.Collect(ch)
			close(ch)
		}()

		count := 0
		for range ch {
			count++
		}
		assert.Equal(t, 2, count, fmt.Sprintf("%#+v", c))
	}
	if t.Failed() {
		t.Errorf("c0: %#+v\ng0: %#+v\ni0: %#+v\nc1: %#+v\ng1: %#+v\ni1: %#+v\n",
			c0, g0, i0, c1, g1, i1)
	}
}

func TestMetricsRegistererDoubleUse(t *testing.T) {
	registry := prometheus.NewRegistry()
	metrics0 := New(registry)
	metrics1 := New(registry)

	// these test cases should panic:

	t.Run("Count", func(t *testing.T) {
		defer func() {
			require.NotNil(t, recover())
		}()

		metrics0.Count("test")
		metrics1.Count("test")
	})

	t.Run("Gauge", func(t *testing.T) {
		defer func() {
			require.NotNil(t, recover())
		}()

		metrics0.Gauge("test")
		metrics1.Gauge("test")
	})

	t.Run("IntGauge", func(t *testing.T) {
		defer func() {
			require.NotNil(t, recover())
		}()

		metrics0.IntGauge("test")
		metrics1.IntGauge("test")
	})
}

func TestMergeSortedStrings(t *testing.T) {
	slices := [][]string{
		{"a", "b", "c"},
		{"r", "a", "n", "d", "o", "m"},
		{"a", "rb", "", "it", "r", "ary"},
	}
	for idx := range slices {
		sort.Strings(slices[idx])
	}
	for _, a := range slices {
		for _, b := range slices {
			t.Run(strings.Join(a, "-")+"_"+strings.Join(b, "-"), func(t *testing.T) {
				m := map[string]struct{}{}
				for _, aItem := range a {
					m[aItem] = struct{}{}
				}
				for _, bItem := range b {
					m[bItem] = struct{}{}
				}
				expected := make([]string, 0, len(m))
				for k := range m {
					expected = append(expected, k)
				}
				sort.Strings(expected)

				require.Equal(t, expected, mergeSortedStrings(a, b...))
			})
		}
	}
}

func TestDisabledLabels(t *testing.T) {
	registry := prometheus.NewRegistry()
	var m metrics.Metrics = New(registry, OptionDisableLabels(true))
	m = m.WithContextFields(((*field.FieldsChain)(nil)).WithField("1", 2), 1).(metrics.Metrics)
	c := m.Count("someCount")
	require.Len(t, c.(*Count).labelNames, 0)
	c = c.WithResetFields(field.Fields{{Key: "3", Value: 4}})
	require.Len(t, c.(*Count).labelNames, 0)
}