kube-prometheus: Add e2e tests

tests/e2e/prometheus_client.go

@@ -0,0 +1,52 @@
+// Copyright 2019 The prometheus-operator 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 e2e
+
+import (
+	"k8s.io/client-go/kubernetes"
+
+	"github.com/Jeffail/gabs"
+)
+
+type prometheusClient struct {
+	kubeClient kubernetes.Interface
+}
+
+func newPrometheusClient(kubeClient kubernetes.Interface) *prometheusClient {
+	return &prometheusClient{kubeClient}
+}
+
+// Query makes a request against the Prometheus /api/v1/query endpoint.
+func (c *prometheusClient) query(query string) (int, error) {
+	req := c.kubeClient.CoreV1().RESTClient().Get().
+		Namespace("monitoring").
+		Resource("pods").
+		SubResource("proxy").
+		Name("prometheus-k8s-0:9090").
+		Suffix("/api/v1/query").Param("query", query)
+
+	b, err := req.DoRaw()
+	if err != nil {
+		return 0, err
+	}
+
+	res, err := gabs.ParseJSON(b)
+	if err != nil {
+		return 0, err
+	}
+
+	n, err := res.ArrayCountP("data.result")
+	return n, err
+}