Stubbing out metric converters.

pkg/custom-provider/external_provider.go

@@ -1,29 +1,14 @@
-/*
-Copyright 2017 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 provider
 
 import (
 	"context"
-	"fmt"
 	"time"
 
 	pmodel "github.com/prometheus/common/model"
 
+	conv "github.com/directxman12/k8s-prometheus-adapter/pkg/custom-provider/metric-converter"
 	"github.com/kubernetes-incubator/custom-metrics-apiserver/pkg/provider"
+
 	apimeta "k8s.io/apimachinery/pkg/api/meta"
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/client-go/dynamic"
@@ -32,16 +17,22 @@ import (
 	prom "github.com/directxman12/k8s-prometheus-adapter/pkg/client"
 )
 
+//TODO: Make sure everything has the proper licensing disclosure at the top.
+//TODO: I'd like to move these files into another directory, but the compiler was giving me
+//some static around unexported types. I'm going to leave things as-is for now, but it
+//might be worthwhile to, once the shared components are discovered, move some things around.
+
 //TODO: Some of these members may not be necessary.
 //Some of them are definitely duplicated between the
 //external and custom providers. They should probably share
 //the same instances of these objects (especially the SeriesRegistry)
 //to cut down on unnecessary chatter/bookkeeping.
 type externalPrometheusProvider struct {
-	mapper       apimeta.RESTMapper
+	mapper          apimeta.RESTMapper
-	kubeClient   dynamic.Interface
+	kubeClient      dynamic.Interface
-	promClient   prom.Client
+	promClient      prom.Client
-	queryBuilder ExternalMetricQueryBuilder
+	queryBuilder    ExternalMetricQueryBuilder
+	metricConverter conv.MetricConverter
 
 	SeriesRegistry
 }
@@ -52,7 +43,8 @@ type externalPrometheusProvider struct {
 //Just glancing at start.go looks like it would be much more straightforward
 //to do one of those two things instead of trying to run the two providers
 //independently.
-func NewExternalPrometheusProvider(mapper apimeta.RESTMapper, kubeClient dynamic.Interface, promClient prom.Client, namers []MetricNamer, updateInterval time.Duration, queryBuilder ExternalMetricQueryBuilder) (provider.ExternalMetricsProvider, Runnable) {
+
+func NewExternalPrometheusProvider(mapper apimeta.RESTMapper, kubeClient dynamic.Interface, promClient prom.Client, namers []MetricNamer, updateInterval time.Duration, queryBuilder ExternalMetricQueryBuilder, metricConverter conv.MetricConverter) (provider.ExternalMetricsProvider, Runnable) {
 	lister := &cachingMetricsLister{
 		updateInterval: updateInterval,
 		promClient:     promClient,
@@ -64,9 +56,10 @@ func NewExternalPrometheusProvider(mapper apimeta.RESTMapper, kubeClient dynamic
 	}
 
 	return &externalPrometheusProvider{
-		mapper:     mapper,
+		mapper:          mapper,
-		kubeClient: kubeClient,
+		kubeClient:      kubeClient,
-		promClient: promClient,
+		promClient:      promClient,
+		metricConverter: metricConverter,
 
 		SeriesRegistry: lister,
 	}, lister
@@ -79,12 +72,13 @@ func (p *externalPrometheusProvider) GetExternalMetric(namespace string, metricN
 	//TODO: I don't yet know what a context is, but apparently I should use a real one.
 	queryResults, err := p.promClient.Query(context.TODO(), pmodel.Now(), selector)
 
-	//TODO: Only here to stop compiler issues in this incomplete code.
+	if err != nil {
-	fmt.Printf("%s, %s", queryResults, err)
+		//TODO: Is this how folks normally deal w/ errors? Just propagate them upwards?
+		//I should go look at what the customProvider does.
+		return nil, err
+	}
 
-	//TODO: Check for errors. See what the custromPrometheusProvider does for errors.
+	return p.metricConverter.Convert(queryResults)
-	//TODO: Adapt the results in queryResults to the appropriate return type.
-	return nil, nil
 }
 
 func (p *externalPrometheusProvider) ListAllExternalMetrics() []provider.ExternalMetricInfo {

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

@@ -0,0 +1,37 @@
+package provider
+
+import (
+	"errors"
+
+	prom "github.com/directxman12/k8s-prometheus-adapter/pkg/client"
+	"github.com/prometheus/common/model"
+	"k8s.io/metrics/pkg/apis/external_metrics"
+)
+
+type matrixConverter struct {
+}
+
+//NewMatrixConverter creates a MatrixConverter capable of converting
+//matrix Prometheus query results into external metric types.
+func NewMatrixConverter() MetricConverter {
+	return &matrixConverter{}
+}
+
+func (c *matrixConverter) Convert(queryResult prom.QueryResult) (*external_metrics.ExternalMetricValueList, error) {
+	if queryResult.Type != model.ValMatrix {
+		return nil, errors.New("matrixConverter can only convert scalar query results")
+	}
+
+	toConvert := queryResult.Matrix
+
+	if toConvert == nil {
+		return nil, errors.New("the provided input did not contain matrix query results")
+	}
+
+	return c.convert(toConvert)
+}
+
+func (c *matrixConverter) convert(result *model.Matrix) (*external_metrics.ExternalMetricValueList, error) {
+	//TODO: Implementation.
+	return nil, nil
+}

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

@@ -0,0 +1,47 @@
+package provider
+
+import (
+	"errors"
+
+	prom "github.com/directxman12/k8s-prometheus-adapter/pkg/client"
+	"github.com/prometheus/common/model"
+	"k8s.io/metrics/pkg/apis/external_metrics"
+)
+
+//MetricConverter provides a unified interface for converting the results of
+//Prometheus queries into external metric types.
+type MetricConverter interface {
+	Convert(queryResult prom.QueryResult) (*external_metrics.ExternalMetricValueList, error)
+}
+
+type metricConverter struct {
+	scalarConverter MetricConverter
+	vectorConverter MetricConverter
+	matrixConverter MetricConverter
+}
+
+//NewMetricConverter creates a MetricCoverter, capable of converting any of the three metric types
+//returned by the Prometheus client into external metrics types.
+func NewMetricConverter(scalar MetricConverter, vector MetricConverter, matrix MetricConverter) MetricConverter {
+	return &metricConverter{
+		scalarConverter: scalar,
+		vectorConverter: vector,
+		matrixConverter: matrix,
+	}
+}
+
+func (c *metricConverter) Convert(queryResult prom.QueryResult) (*external_metrics.ExternalMetricValueList, error) {
+	if queryResult.Type == model.ValScalar {
+		return c.scalarConverter.Convert(queryResult)
+	}
+
+	if queryResult.Type == model.ValVector {
+		return c.vectorConverter.Convert(queryResult)
+	}
+
+	if queryResult.Type == model.ValMatrix {
+		return c.matrixConverter.Convert(queryResult)
+	}
+
+	return nil, errors.New("encountered an unexpected query result type")
+}

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
+}

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

@@ -0,0 +1,37 @@
+package provider
+
+import (
+	"errors"
+
+	prom "github.com/directxman12/k8s-prometheus-adapter/pkg/client"
+	"github.com/prometheus/common/model"
+	"k8s.io/metrics/pkg/apis/external_metrics"
+)
+
+type vectorConverter struct {
+}
+
+//NewVectorConverter creates a VectorConverter capable of converting
+//vector Prometheus query results into external metric types.
+func NewVectorConverter() MetricConverter {
+	return &vectorConverter{}
+}
+
+func (c *vectorConverter) Convert(queryResult prom.QueryResult) (*external_metrics.ExternalMetricValueList, error) {
+	if queryResult.Type != model.ValVector {
+		return nil, errors.New("vectorConverter can only convert scalar query results")
+	}
+
+	toConvert := queryResult.Vector
+
+	if toConvert == nil {
+		return nil, errors.New("the provided input did not contain vector query results")
+	}
+
+	return c.convert(toConvert)
+}
+
+func (c *vectorConverter) convert(result *model.Vector) (*external_metrics.ExternalMetricValueList, error) {
+	//TODO: Implementation.
+	return nil, nil
+}