More implementation work in conversion.

Notable next steps include:
* Intelligently select the aggregation method (rate/avg_over_time/etc).
* Intelligenty select the aggregation window.
* Figure out how to handle "namespace", if at all.
* Fix the crazy type conversion in `sample_converter.go`.

pkg/custom-provider/external_metric_query_builder.go

@@ -4,12 +4,13 @@ import (
 	"fmt"
 	s "strings"
 
+	provider "github.com/directxman12/k8s-prometheus-adapter/pkg/custom-provider/metric-converter"
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/selection"
 )
 
 type ExternalMetricQueryBuilder interface {
-	BuildPrometheusQuery(namespace string, metricName string, metricSelector labels.Selector) string
+	BuildPrometheusQuery(namespace string, metricName string, metricSelector labels.Selector, queryMetadata provider.QueryMetadata) string
 }
 
 type externalMetricQueryBuilder struct {
@@ -19,13 +20,27 @@ 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)
+func (p *externalMetricQueryBuilder) BuildPrometheusQuery(namespace string, metricName string, metricSelector labels.Selector, queryMetadata provider.QueryMetadata) string {
+	//TODO: At least for my Prometheus install, the "namespace" label doesn't seem to be
+	//directly applied to the time series. I'm using prometheus-operator. The grafana dashboards
+	//seem to query for the pods in a namespace from kube_pod_info and then apply pod-specific
+	//label filters. This might need some more thought. Disabling for now.
+	// namespaceSelector := p.makeLabelFilter("namespace", "=", namespace)
+	labelSelectors := p.convertSelectors(metricSelector)
+	joinedLabels := s.Join(labelSelectors, ", ")
 
-	finalTargets := append([]string{namespaceSelector}, otherSelectors...)
-	joinedLabels := s.Join(finalTargets, ", ")
-	return fmt.Sprintf("%s{%s}", metricName, joinedLabels)
+	//TODO: Both the aggregation method and window should probably be configurable.
+	//I don't think we can make assumptions about the nature of someone's metrics.
+	//I'm guessing this might be covered by the recently added advanced configuration
+	//code, but I haven't yet had an opportunity to dig into that and understand it.
+	//We'll leave this here for testing purposes for now.
+	//As reasonable defaults, maybe:
+	//rate(...) for counters
+	//avg_over_time(...) for gauges
+	//I'm guessing that SeriesRegistry might store the metric type, but I haven't looked yet.
+	aggregation := queryMetadata.Aggregation
+	window := queryMetadata.WindowInSeconds
+	return fmt.Sprintf("%s(%s{%s}[%ss])", aggregation, metricName, joinedLabels, window)
 }
 
 func (p *externalMetricQueryBuilder) makeLabelFilter(labelName string, operator string, targetValue string) string {
@@ -72,7 +87,9 @@ func (p *externalMetricQueryBuilder) selectOperator(operator selection.Operator,
 func (p *externalMetricQueryBuilder) selectRegexOperator(operator selection.Operator) string {
 	switch operator {
 	case selection.Equals:
+	case selection.In:
 		return "=~"
+	case selection.NotIn:
 	case selection.NotEquals:
 		return "!~"
 	}

pkg/custom-provider/external_provider.go

@@ -66,7 +66,14 @@ func NewExternalPrometheusProvider(mapper apimeta.RESTMapper, kubeClient dynamic
 }
 
 func (p *externalPrometheusProvider) GetExternalMetric(namespace string, metricName string, metricSelector labels.Selector) (*external_metrics.ExternalMetricValueList, error) {
-	query := p.queryBuilder.BuildPrometheusQuery(namespace, metricName, metricSelector)
+	//TODO: Get the appropriate time window and aggregation type from somewhere
+	//based on the metric being selected. Does SeriesRegistry have the metric type cached?
+	queryMetadata := conv.QueryMetadata{
+		MetricName:      metricName,
+		WindowInSeconds: 120,
+		Aggregation:     "rate",
+	}
+	query := p.queryBuilder.BuildPrometheusQuery(namespace, metricName, metricSelector, queryMetadata)
 	selector := prom.Selector(query)
 
 	//TODO: I don't yet know what a context is, but apparently I should use a real one.
@@ -78,10 +85,6 @@ func (p *externalPrometheusProvider) GetExternalMetric(namespace string, metricN
 		return nil, err
 	}
 
-	queryMetadata := conv.QueryMetadata{
-		MetricName:      metricName,
-		WindowInSeconds: 0,
-	}
 	return p.metricConverter.Convert(queryMetadata, queryResults)
 }
 

pkg/custom-provider/metric-converter/matrix_converter.go

@@ -33,5 +33,5 @@ func (c *matrixConverter) Convert(metadata QueryMetadata, queryResult prom.Query
 
 func (c *matrixConverter) convert(result *model.Matrix) (*external_metrics.ExternalMetricValueList, error) {
 	//TODO: Implementation.
-	return nil, nil
+	return nil, errors.New("converting Matrix results is not yet supported")
 }

pkg/custom-provider/metric-converter/query_metadata.go

@@ -8,4 +8,6 @@ package provider
 type QueryMetadata struct {
 	MetricName      string
 	WindowInSeconds int64
+	//TODO: Type this?
+	Aggregation string
 }

pkg/custom-provider/metric-converter/sample_converter.go

@@ -0,0 +1,53 @@
+package provider
+
+import (
+	"github.com/prometheus/common/model"
+	"k8s.io/apimachinery/pkg/api/resource"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/metrics/pkg/apis/external_metrics"
+)
+
+type sampleConverter struct {
+}
+
+//SampleConverter is capable of translating Prometheus Sample objects
+//into ExternamMetricValue objects.
+type SampleConverter interface {
+	Convert(metadata QueryMetadata, sample *model.Sample) (*external_metrics.ExternalMetricValue, error)
+}
+
+//NewSampleConverter creates a SampleConverter capable of translating Prometheus Sample objects
+//into ExternamMetricValue objects.
+func NewSampleConverter() SampleConverter {
+	return &sampleConverter{}
+}
+
+func (c *sampleConverter) Convert(metadata QueryMetadata, sample *model.Sample) (*external_metrics.ExternalMetricValue, error) {
+	labels := c.convertLabels(sample.Metric)
+
+	singleMetric := external_metrics.ExternalMetricValue{
+		MetricName: string(sample.Metric[model.LabelName("__name__")]),
+		Timestamp: metav1.Time{
+			sample.Timestamp.Time(),
+		},
+		WindowSeconds: &metadata.WindowInSeconds,
+		//TODO: I'm not so sure about this type/conversions.
+		//This can't possibly be the right way to convert this.
+		//Also, does K8S only deal win integer metrics?
+		Value:        *resource.NewQuantity(int64(float64(sample.Value)), resource.DecimalSI),
+		MetricLabels: labels,
+	}
+
+	//TODO: Actual errors?
+	return &singleMetric, nil
+}
+
+func (c *sampleConverter) convertLabels(inLabels model.Metric) map[string]string {
+	numLabels := len(inLabels)
+	outLabels := make(map[string]string, numLabels)
+	for labelName, labelVal := range inLabels {
+		outLabels[string(labelName)] = string(labelVal)
+	}
+
+	return outLabels
+}

pkg/custom-provider/metric-converter/vector_converter.go

@@ -5,18 +5,19 @@ import (
 
 	prom "github.com/directxman12/k8s-prometheus-adapter/pkg/client"
 	"github.com/prometheus/common/model"
-	"k8s.io/apimachinery/pkg/api/resource"
-	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/metrics/pkg/apis/external_metrics"
 )
 
 type vectorConverter struct {
+	SampleConverter SampleConverter
 }
 
 //NewVectorConverter creates a VectorConverter capable of converting
 //vector Prometheus query results into external metric types.
-func NewVectorConverter() MetricConverter {
-	return &vectorConverter{}
+func NewVectorConverter(sampleConverter *SampleConverter) MetricConverter {
+	return &vectorConverter{
+		SampleConverter: *sampleConverter,
+	}
 }
 
 func (c *vectorConverter) Convert(metadata QueryMetadata, queryResult prom.QueryResult) (*external_metrics.ExternalMetricValueList, error) {
@@ -45,20 +46,13 @@ func (c *vectorConverter) convert(metadata QueryMetadata, result model.Vector) (
 	}
 
 	for _, val := range result {
-		singleMetric := external_metrics.ExternalMetricValue{
-			MetricName: string(val.Metric[model.LabelName("__name__")]),
-			Timestamp: metav1.Time{
-				val.Timestamp.Time(),
-			},
-			WindowSeconds: &metadata.WindowInSeconds,
-			//TODO: I'm not so sure about this type/conversions.
-			//This can't possibly be the right way to convert this.
-			//Also, does K8S only deal win integer metrics?
-			Value: *resource.NewQuantity(int64(float64(val.Value)), resource.DecimalSI),
-		}
-
-		items = append(items, singleMetric)
+		//TODO: Care about potential errors here.
+		singleMetric, _ := c.SampleConverter.Convert(metadata, val)
+		items = append(items, *singleMetric)
 	}
 
+	metricValueList = external_metrics.ExternalMetricValueList{
+		Items: items,
+	}
 	return &metricValueList, nil
 }