repo_description: Configure external DNS servers dynamically from Kubernetes resources
repo_topics: aws clouddns dns dns-controller dns-providers dns-record dns-servers external-dns gcp ingress k8s-sig-network kubernetes route53
code: /*
  Copyright 2025 The Kubernetes Authors.
  
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
  
      http://www.apache.org/licenses/LICENSE-2.0
  
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
  */
  
  package metrics
  
  import (
  	"reflect"
  	"runtime"
  	"testing"
  
  	"github.com/prometheus/client_golang/prometheus"
  	dto "github.com/prometheus/client_model/go"
  	"github.com/stretchr/testify/assert"
  	"github.com/stretchr/testify/require"
  )
  
  func TestNewGaugeWithOpts(t *testing.T) {
  	opts := prometheus.GaugeOpts{
  		Name:      "test_gauge",
  		Subsystem: "test_subsystem",
  		Help:      "This is a test gauge",
  	}
  
  	gaugeMetric := NewGaugeWithOpts(opts)
  
  	assert.Equal(t, "gauge", gaugeMetric.Type)
  	assert.Equal(t, "test_gauge", gaugeMetric.Name)
  	assert.Equal(t, Namespace, gaugeMetric.Namespace)
  	assert.Equal(t, "test_subsystem", gaugeMetric.Subsystem)
  	assert.Equal(t, "This is a test gauge", gaugeMetric.Help)
  	assert.Equal(t, "test_subsystem_test_gauge", gaugeMetric.FQDN)
  	assert.NotNil(t, gaugeMetric.Gauge)
  }
  
  func TestNewCounterWithOpts(t *testing.T) {
  	opts := prometheus.CounterOpts{
  		Name:      "test_counter",
  		Subsystem: "test_subsystem",
  		Help:      "This is a test counter",
  	}
  
  	counterMetric := NewCounterWithOpts(opts)
  
  	assert.Equal(t, "counter", counterMetric.Type)
  	assert.Equal(t, "test_counter", counterMetric.Name)
  	assert.Equal(t, Namespace, counterMetric.Namespace)
  	assert.Equal(t, "test_subsystem", counterMetric.Subsystem)
  	assert.Equal(t, "This is a test counter", counterMetric.Help)
  	assert.Equal(t, "test_subsystem_test_counter", counterMetric.FQDN)
  	assert.NotNil(t, counterMetric.Counter)
  }
  
  func TestNewCounterVecWithOpts(t *testing.T) {
  	opts := prometheus.CounterOpts{
  		Name:      "test_counter_vec",
  		Namespace: "test_namespace",
  		Subsystem: "test_subsystem",
  		Help:      "This is a test counter vector",
  	}
  
  	labelNames := []string{"label1", "label2"}
  
  	counterVecMetric := NewCounterVecWithOpts(opts, labelNames)
  
  	assert.Equal(t, "counter", counterVecMetric.Type)
  	assert.Equal(t, "test_counter_vec", counterVecMetric.Name)
  	assert.Equal(t, Namespace, counterVecMetric.Namespace)
  	assert.Equal(t, "test_subsystem", counterVecMetric.Subsystem)
  	assert.Equal(t, "This is a test counter vector", counterVecMetric.Help)
  	assert.Equal(t, "test_subsystem_test_counter_vec", counterVecMetric.FQDN)
  	assert.NotNil(t, counterVecMetric.CounterVec)
  }
  
  func TestGaugeV_SetWithLabels(t *testing.T) {
  	opts := prometheus.GaugeOpts{
  		Name:      "test_gauge",
  		Namespace: "test_ns",
  		Subsystem: "test_sub",
  		Help:      "help text",
  	}
  	gv := NewGaugedVectorOpts(opts, []string{"label1", "label2"})
  
  	gv.SetWithLabels(1.23, "Alpha", "BETA")
  
  	g, err := gv.Gauge.GetMetricWithLabelValues("alpha", "beta")
  	assert.NoError(t, err)
  
  	var m dto.Metric
  	err = g.Write(&m)
  	assert.NoError(t, err)
  	assert.NotNil(t, m.Gauge)
  	assert.InDelta(t, 1.23, *m.Gauge.Value, 0.01)
  
  	// Override the value
  	gv.SetWithLabels(4.56, "ALPHA", "beta")
  	// reuse g (same label combination)
  	err = g.Write(&m)
  	assert.NoError(t, err)
  	assert.InDelta(t, 4.56, *m.Gauge.Value, 0.01)
  
  	assert.Len(t, m.Label, 2)
  }
  
  func TestNewGaugeFuncMetric(t *testing.T) {
  	tests := []struct {
  		name                    string
  		metricName              string
  		subSystem               string
  		constLabels             prometheus.Labels
  		expectedFqName          string
  		expectedDescString      string
  		expectedGaugeFuncReturn float64
  	}{
  		{
  			name:       "NewGaugeFuncMetric returns build_info",
  			metricName: "build_info",
  			subSystem:  "",
  			constLabels: prometheus.Labels{
  				"version":   "0.0.1",
  				"goversion": runtime.Version(),
  				"arch":      "arm64",
  			},
  			expectedFqName:          "external_dns_build_info",
  			expectedDescString:      "version=\"0.0.1\"",
  			expectedGaugeFuncReturn: 1,
  		},
  		{
  			name:                    "NewGaugeFuncMetric subsystem alters name",
  			metricName:              "metricName",
  			subSystem:               "subSystem",
  			constLabels:             prometheus.Labels{},
  			expectedFqName:          "external_dns_subSystem_metricName",
  			expectedDescString:      "",
  			expectedGaugeFuncReturn: 1,
  		},
  		{
  			name:                    "NewGaugeFuncMetric GaugeFunc returns 1",
  			metricName:              "metricName",
  			subSystem:               "",
  			constLabels:             prometheus.Labels{},
  			expectedFqName:          "external_dns_metricName",
  			expectedDescString:      "",
  			expectedGaugeFuncReturn: 1,
  		},
  	}
  
  	for _, tt := range tests {
  		t.Run(tt.name, func(t *testing.T) {
  			metric := NewGaugeFuncMetric(prometheus.GaugeOpts{
  				Namespace:   Namespace,
  				Name:        tt.metricName,
  				Subsystem:   tt.subSystem,
  				ConstLabels: tt.constLabels,
  			})
  
  			desc := metric.GaugeFunc.Desc()
  
  			assert.Equal(t, tt.expectedFqName, reflect.ValueOf(desc).Elem().FieldByName("fqName").String())
  			assert.Contains(t, desc.String(), tt.expectedDescString)
  
  			testRegistry := prometheus.NewRegistry()
  			err := testRegistry.Register(metric.GaugeFunc)
  			require.NoError(t, err)
  
  			metricFamily, err := testRegistry.Gather()
  			require.NoError(t, err)
  			require.Len(t, metricFamily, 1)
  
  			require.NotNil(t, metricFamily[0].Metric[0].Gauge)
  			assert.InDelta(t, tt.expectedGaugeFuncReturn, metricFamily[0].Metric[0].GetGauge().GetValue(), 0.0001)
  		})
  	}
  }
  
  func TestSummaryV_SetWithLabels(t *testing.T) {
  	opts := prometheus.SummaryOpts{
  		Name:      "test_summaryVec",
  		Namespace: "test_ns",
  		Subsystem: "test_sub",
  		Help:      "help text",
  	}
  
  	labels := Labels{}
  	sv := NewSummaryVecWithOpts(opts, []string{"label1", "label2"})
  
  	labels["label1"] = "alpha"
  	labels["label2"] = "beta"
  
  	sv.SetWithLabels(5.01, labels)
  
  	reg := prometheus.NewRegistry()
  	reg.MustRegister(sv.SummaryVec)
  
  	metricsFamilies, err := reg.Gather()
  	assert.NoError(t, err)
  	assert.Len(t, metricsFamilies, 1)
  
  	s, err := sv.SummaryVec.GetMetricWithLabelValues("alpha", "beta")
  	assert.NoError(t, err)
  	metricsFamilies, err = reg.Gather()
  
  	s.Observe(5.21)
  	metricsFamilies, err = reg.Gather()
  	assert.NoError(t, err)
  
  	assert.InDelta(t, 10.22, *metricsFamilies[0].Metric[0].Summary.SampleSum, 0.01)
  	assert.Len(t, metricsFamilies[0].Metric[0].Label, 2)
  }
  
  func TestPathProcessor(t *testing.T) {
  	tests := []struct {
  		input    string
  		expected string
  	}{
  		{"/foo/bar", "bar"},
  		{"/foo/", ""},
  		{"/", ""},
  		{"", ""},
  		{"/foo/bar/baz", "baz"},
  		{"foo/bar", "bar"},
  		{"foo", "foo"},
  		{"foo/", ""},
  	}
  
  	for _, tt := range tests {
  		t.Run(tt.input, func(t *testing.T) {
  			require.Equal(t, tt.expected, PathProcessor(tt.input))
  		})
  	}
  }
  
  func TestGaugeV_AddWithLabels(t *testing.T) {
  	opts := prometheus.GaugeOpts{
  		Name:      "test_gauge_add",
  		Namespace: "test_ns",
  		Subsystem: "test_sub",
  		Help:      "help text",
  	}
  	gv := NewGaugedVectorOpts(opts, []string{"label1", "label2"})
  
  	// Add with mixed case labels - should be lowercased
  	gv.AddWithLabels(1.0, "Alpha", "BETA")
  
  	g, err := gv.Gauge.GetMetricWithLabelValues("alpha", "beta")
  	assert.NoError(t, err)
  
  	var m dto.Metric
  	err = g.Write(&m)
  	assert.NoError(t, err)
  	assert.NotNil(t, m.Gauge)
  	assert.InDelta(t, 1.0, *m.Gauge.Value, 0.01)
  
  	// Add again - should increment, not override
  	gv.AddWithLabels(2.0, "ALPHA", "beta")
  	err = g.Write(&m)
  	assert.NoError(t, err)
  	assert.InDelta(t, 3.0, *m.Gauge.Value, 0.01) // 1.0 + 2.0 = 3.0
  
  	// Add one more time
  	gv.AddWithLabels(0.5, "alpha", "Beta")
  	err = g.Write(&m)
  	assert.NoError(t, err)
  	assert.InDelta(t, 3.5, *m.Gauge.Value, 0.01) // 3.0 + 0.5 = 3.5
  
  	assert.Len(t, m.Label, 2)
  }
  