Stubbing out metric converters.

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

@@ -0,0 +1,68 @@
+package provider
+
+import (
+	"errors"
+
+	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 scalarConverter struct {
+}
+
+//NewScalarConverter creates a ScalarConverter capable of converting
+//scalar Prometheus query results into external metric types.
+func NewScalarConverter() MetricConverter {
+	return &scalarConverter{}
+}
+
+func (c *scalarConverter) Convert(queryResult prom.QueryResult) (*external_metrics.ExternalMetricValueList, error) {
+	if queryResult.Type != model.ValScalar {
+		return nil, errors.New("scalarConverter can only convert scalar query results")
+	}
+
+	toConvert := queryResult.Scalar
+
+	if toConvert == nil {
+		return nil, errors.New("the provided input did not contain scalar query results")
+	}
+
+	return c.convert(toConvert)
+}
+
+func (c *scalarConverter) convert(input *model.Scalar) (*external_metrics.ExternalMetricValueList, error) {
+	tempWindow := int64(0)
+	result := external_metrics.ExternalMetricValueList{
+		//TODO: Where should all of these values come from?
+		TypeMeta: metav1.TypeMeta{
+			Kind:       "?",
+			APIVersion: "?",
+		},
+		ListMeta: metav1.ListMeta{
+			SelfLink:        "?",
+			ResourceVersion: "?",
+			Continue:        "?",
+		},
+		Items: []external_metrics.ExternalMetricValue{
+			external_metrics.ExternalMetricValue{
+				TypeMeta: metav1.TypeMeta{
+					Kind:       "?",
+					APIVersion: "?",
+				},
+				//TODO: Carry forward the metric name so we can set it here.
+				MetricName: "?",
+				Timestamp: metav1.Time{
+					input.Timestamp.Time(),
+				},
+				//TODO: Carry forward some information about our configuration so we can provide it here.
+				WindowSeconds: &tempWindow,
+				//TODO: Jump through the necessary hoops to convert our number into the proper type.
+				Value: resource.Quantity{},
+			},
+		},
+	}
+	return &result, nil
+}