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Moving the query building logic, adding first unit test.

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Moving it into its own type to better organize and separate concerns. Also makes unit testing easier.
This commit is contained in:
Tony Compton 2018-06-27 21:37:21 -04:00
parent e9af0455ba
commit 3727f99343
3 changed files with 124 additions and 76 deletions
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94
pkg/custom-provider/external_metric_query_builder.go Normal file
View file

@ -0,0 +1,94 @@
package provider
import (
"fmt"
s "strings"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/apimachinery/pkg/selection"
)
type ExternalMetricQueryBuilder interface {
BuildPrometheusQuery(namespace string, metricName string, metricSelector labels.Selector) string
}
type externalMetricQueryBuilder struct {
}
func NewExternalMetricQueryBuilder() ExternalMetricQueryBuilder {
return &externalMetricQueryBuilder{}
}
func (p *externalMetricQueryBuilder) BuildPrometheusQuery(namespace string, metricName string, metricSelector labels.Selector) string {
namespaceSelector := p.makeLabelFilter("namespace", "=", namespace)
otherSelectors := p.convertSelectors(metricSelector)
finalTargets := append([]string{namespaceSelector}, otherSelectors...)
joinedLabels := s.Join(finalTargets, ", ")
return fmt.Sprintf("%s{%s}", metricName, joinedLabels)
}
func (p *externalMetricQueryBuilder) makeLabelFilter(labelName string, operator string, targetValue string) string {
return fmt.Sprintf("%s%s\"%s\"", labelName, operator, targetValue)
}
func (p *externalMetricQueryBuilder) convertSelectors(metricSelector labels.Selector) []string {
requirements, _ := metricSelector.Requirements()
selectors := []string{}
for i := 0; i < len(requirements); i++ {
selector := p.convertRequirement(requirements[i])
selectors = append(selectors, selector)
}
return selectors
}
func (p *externalMetricQueryBuilder) convertRequirement(requirement labels.Requirement) string {
labelName := requirement.Key()
values := requirement.Values().List()
stringValues := values[0]
valueCount := len(values)
if valueCount > 1 {
stringValues = s.Join(values, "|")
}
operator := p.selectOperator(requirement.Operator(), valueCount)
return p.makeLabelFilter(labelName, operator, stringValues)
}
func (p *externalMetricQueryBuilder) selectOperator(operator selection.Operator, valueCount int) string {
if valueCount > 1 {
return p.selectRegexOperator(operator)
}
return p.selectSingleValueOperator(operator)
}
func (p *externalMetricQueryBuilder) selectRegexOperator(operator selection.Operator) string {
switch operator {
case selection.Equals:
return "=~"
case selection.NotEquals:
return "!~"
}
//TODO: Cover more cases, supply appropriate errors for any unhandled cases.
return "="
}
func (p *externalMetricQueryBuilder) selectSingleValueOperator(operator selection.Operator) string {
switch operator {
case selection.Equals:
return "="
case selection.NotEquals:
return "!="
}
//TODO: Cover more cases, supply appropriate errors for any unhandled cases.
return "="
}

23
pkg/custom-provider/external_metric_query_builder_test.go Normal file
View file

@ -0,0 +1,23 @@
package provider
import (
"testing"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/apimachinery/pkg/selection"
)
var queryBuilder = NewExternalMetricQueryBuilder()
func TestBuildPrometheusQuery(t *testing.T) {
fakeSelector := labels.NewSelector()
requirement, _ := labels.NewRequirement("queue_name", selection.Equals, []string{"processing"})
fakeSelector = fakeSelector.Add(*requirement)
result := queryBuilder.BuildPrometheusQuery("default", "queue_length", fakeSelector)
expectedResult := "queue_length{namespace=\"default\", queue_name=\"processing\"}"
if result != expectedResult {
t.Errorf("Incorrect query generated. Expected: %s | Actual %s", result, expectedResult)
}
}

83
pkg/custom-provider/external_provider.go
View file

@ -18,13 +18,11 @@ package provider
import (
"fmt"
s "strings"
"time"
"github.com/kubernetes-incubator/custom-metrics-apiserver/pkg/provider"
apimeta "k8s.io/apimachinery/pkg/api/meta"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/apimachinery/pkg/selection"
"k8s.io/client-go/dynamic"
"k8s.io/metrics/pkg/apis/external_metrics"
@ -32,14 +30,15 @@ import (
)
type externalPrometheusProvider struct {
mapper apimeta.RESTMapper
kubeClient dynamic.Interface
promClient prom.Client
mapper apimeta.RESTMapper
kubeClient dynamic.Interface
promClient prom.Client
queryBuilder ExternalMetricQueryBuilder
SeriesRegistry
}
func NewExternalPrometheusProvider(mapper apimeta.RESTMapper, kubeClient dynamic.Interface, promClient prom.Client, namers []MetricNamer, updateInterval time.Duration) (provider.ExternalMetricsProvider, Runnable) {
func NewExternalPrometheusProvider(mapper apimeta.RESTMapper, kubeClient dynamic.Interface, promClient prom.Client, namers []MetricNamer, updateInterval time.Duration, queryBuilder ExternalMetricQueryBuilder) (provider.ExternalMetricsProvider, Runnable) {
lister := &cachingMetricsLister{
updateInterval: updateInterval,
promClient: promClient,
@ -69,83 +68,15 @@ func (p *externalPrometheusProvider) GetExternalMetric(namespace string, metricN
//than for custom metrics because no renaming is applied.
//So we'll just start with some simple string operations and see how far that gets us.
//Then I'll circle back and figure out how much code reuse I can get out of the original implementation.
namespaceSelector := p.makeLabelFilter("namespace", "=", namespace)
otherSelectors := p.convertSelectors(metricSelector)
finalTargets := append([]string{namespaceSelector}, otherSelectors...)
query := p.queryBuilder.BuildPrometheusQuery(namespace, metricName, metricSelector)
//TODO: Only here to stop compiler issues in this incomplete code.
fmt.Printf("len=%d", len(finalTargets))
fmt.Printf(query)
//TODO: Construct a real result.
return nil, nil
}
func (p *externalPrometheusProvider) makeLabelFilter(labelName string, operator string, targetValue string) string {
return fmt.Sprintf("%s%s\"%s\"", labelName, operator, targetValue)
}
func (p *externalPrometheusProvider) convertSelectors(metricSelector labels.Selector) []string {
requirements, _ := metricSelector.Requirements()
selectors := []string{}
for i := 0; i < len(requirements); i++ {
selector := p.convertRequirement(requirements[i])
selectors = append(selectors, selector)
}
return selectors
}
func (p *externalPrometheusProvider) convertRequirement(requirement labels.Requirement) string {
labelName := requirement.Key()
values := requirement.Values().List()
stringValues := values[0]
valueCount := len(values)
if valueCount > 1 {
stringValues = s.Join(values, "|")
}
operator := p.selectOperator(requirement.Operator(), valueCount)
return p.makeLabelFilter(labelName, operator, stringValues)
}
func (p *externalPrometheusProvider) selectOperator(operator selection.Operator, valueCount int) string {
if valueCount > 1 {
return p.selectRegexOperator(operator)
}
return p.selectSingleValueOperator(operator)
}
func (p *externalPrometheusProvider) selectRegexOperator(operator selection.Operator) string {
switch operator {
case selection.Equals:
return "=~"
case selection.NotEquals:
return "!~"
}
//TODO: Cover more cases, supply appropriate errors for any unhandled cases.
return "="
}
func (p *externalPrometheusProvider) selectSingleValueOperator(operator selection.Operator) string {
switch operator {
case selection.Equals:
return "="
case selection.NotEquals:
return "!="
}
//TODO: Cover more cases, supply appropriate errors for any unhandled cases.
return "="
}
func (p *externalPrometheusProvider) ListAllExternalMetrics() []provider.ExternalMetricInfo {
//TODO: Provide a real response.
return nil