Merge pull request #158 from linux-on-ibm-z/cross-compile

Edited Makefile to add cross build support for s390x.

Adding External Metrics Provider

pkg/external-provider/provider.go

@@ -0,0 +1,79 @@
+package provider
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"k8s.io/apimachinery/pkg/runtime/schema"
+
+	"github.com/golang/glog"
+	pmodel "github.com/prometheus/common/model"
+
+	"github.com/kubernetes-incubator/custom-metrics-apiserver/pkg/provider"
+
+	apierr "k8s.io/apimachinery/pkg/api/errors"
+	apimeta "k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/labels"
+	"k8s.io/metrics/pkg/apis/external_metrics"
+
+	prom "github.com/directxman12/k8s-prometheus-adapter/pkg/client"
+)
+
+// TODO: Make sure everything has the proper licensing disclosure at the top.
+type externalPrometheusProvider struct {
+	promClient      prom.Client
+	metricConverter MetricConverter
+
+	seriesRegistry ExternalSeriesRegistry
+}
+
+func (p *externalPrometheusProvider) GetExternalMetric(namespace string, metricSelector labels.Selector, info provider.ExternalMetricInfo) (*external_metrics.ExternalMetricValueList, error) {
+	selector, found, err := p.seriesRegistry.QueryForMetric(namespace, info.Metric, metricSelector)
+
+	if err != nil {
+		glog.Errorf("unable to generate a query for the metric: %v", err)
+		return nil, apierr.NewInternalError(fmt.Errorf("unable to fetch metrics"))
+	}
+
+	if !found {
+		return nil, provider.NewMetricNotFoundError(p.selectGroupResource(namespace), info.Metric)
+	}
+
+	queryResults, err := p.promClient.Query(context.TODO(), pmodel.Now(), selector)
+
+	if err != nil {
+		glog.Errorf("unable to fetch metrics from prometheus: %v", err)
+		// don't leak implementation details to the user
+		return nil, apierr.NewInternalError(fmt.Errorf("unable to fetch metrics"))
+	}
+	return p.metricConverter.Convert(queryResults)
+}
+
+func (p *externalPrometheusProvider) ListAllExternalMetrics() []provider.ExternalMetricInfo {
+	return p.seriesRegistry.ListAllMetrics()
+}
+
+func (p *externalPrometheusProvider) selectGroupResource(namespace string) schema.GroupResource {
+	if namespace == "default" {
+		return nsGroupResource
+	}
+
+	return schema.GroupResource{
+		Group:    "",
+		Resource: "",
+	}
+}
+
+// NewExternalPrometheusProvider creates an ExternalMetricsProvider capable of responding to Kubernetes requests for external metric data
+func NewExternalPrometheusProvider(mapper apimeta.RESTMapper, promClient prom.Client, converters []SeriesConverter, updateInterval time.Duration) (provider.ExternalMetricsProvider, Runnable) {
+	metricConverter := NewMetricConverter()
+	basicLister := NewBasicMetricLister(promClient, converters, updateInterval)
+	periodicLister, _ := NewPeriodicMetricLister(basicLister, updateInterval)
+	seriesRegistry := NewExternalSeriesRegistry(periodicLister, mapper)
+	return &externalPrometheusProvider{
+		promClient:      promClient,
+		seriesRegistry:  seriesRegistry,
+		metricConverter: metricConverter,
+	}, periodicLister
+}