test/e2e: Refactor framework setup & wait for query logic

- Instead of counting the returned time series, inspect the first and only
  returned value from a query. This enables checking specific timeseries values.
  The previous behavior can still be achieved by using the `count` PromQL
  function.

- Introduce `waitForQueryReturn{GreaterEqualOne,One}` helper functions for easier
  access.

- Intialize Prometheus client at test framework creation time, as more function
  will need to use it in the long run.

- Wait for Prometheus k8s before running any tests as multiple of them depend on
  its existence.

test/e2e/framework/framework.go

@@ -35,63 +35,76 @@ import (
 var namespaceName = "openshift-monitoring"
 
 type Framework struct {
-	OperatorClient       *client.Client
-	CRDClient            crdc.CustomResourceDefinitionInterface
-	KubeClient           kubernetes.Interface
-	OpenshiftRouteClient routev1.RouteV1Interface
+	OperatorClient      *client.Client
+	CRDClient           crdc.CustomResourceDefinitionInterface
+	KubeClient          kubernetes.Interface
+	PrometheusK8sClient *PrometheusClient
 
 	MonitoringClient *monClient.MonitoringV1Client
 	Ns               string
 }
 
-func New(kubeConfigPath string) (*Framework, error) {
+// New returns a new cluster monitoring operator end-to-end test framework and
+// triggers all the setup logic.
+func New(kubeConfigPath string) (*Framework, cleanUpFunc, error) {
 	config, err := clientcmd.BuildConfigFromFlags("", kubeConfigPath)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 
 	kubeClient, err := kubernetes.NewForConfig(config)
 	if err != nil {
-		return nil, errors.Wrap(err, "creating kubeClient failed")
+		return nil, nil, errors.Wrap(err, "creating kubeClient failed")
 	}
 
+	// So far only necessary for prometheusK8sClient.
 	openshiftRouteClient, err := routev1.NewForConfig(config)
 	if err != nil {
-		return nil, errors.Wrap(err, "creating openshiftClient failed")
+		return nil, nil, errors.Wrap(err, "creating openshiftClient failed")
 	}
 
 	mClient, err := monClient.NewForConfig(config)
 	if err != nil {
-		return nil, errors.Wrap(err, "creating monitoring client failed")
+		return nil, nil, errors.Wrap(err, "creating monitoring client failed")
 	}
 
 	eclient, err := apiextensionsclient.NewForConfig(config)
 	if err != nil {
-		return nil, errors.Wrap(err, "creating extensions client failed")
+		return nil, nil, errors.Wrap(err, "creating extensions client failed")
 	}
 	crdClient := eclient.ApiextensionsV1beta1().CustomResourceDefinitions()
 
 	operatorClient, err := client.New(config, "", namespaceName, "")
 	if err != nil {
-		return nil, errors.Wrap(err, "creating operator client failed")
+		return nil, nil, errors.Wrap(err, "creating operator client failed")
 	}
 
 	f := &Framework{
-		OperatorClient:       operatorClient,
-		KubeClient:           kubeClient,
-		OpenshiftRouteClient: openshiftRouteClient,
-		CRDClient:            crdClient,
-		MonitoringClient:     mClient,
-		Ns:                   namespaceName,
+		OperatorClient:   operatorClient,
+		KubeClient:       kubeClient,
+		CRDClient:        crdClient,
+		MonitoringClient: mClient,
+		Ns:               namespaceName,
+	}
+
+	cleanUp, err := f.setup()
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "failed to setup test framework")
+	}
+
+	// Prometheus client depends on setup above.
+	f.PrometheusK8sClient, err = NewPrometheusClient(openshiftRouteClient, kubeClient)
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "creating prometheusK8sClient failed")
 	}
 
-	return f, nil
+	return f, cleanUp, nil
 }
 
 type cleanUpFunc func() error
 
-// Setup creates everything necessary to use the test framework.
-func (f *Framework) Setup() (cleanUpFunc, error) {
+// setup creates everything necessary to use the test framework.
+func (f *Framework) setup() (cleanUpFunc, error) {
 	cleanUpFuncs := []cleanUpFunc{}
 
 	cf, err := f.CreateServiceAccount()

test/e2e/framework/prometheus_client.go

@@ -16,11 +16,16 @@ package framework
 
 import (
 	"crypto/tls"
+	"fmt"
 	"io/ioutil"
 	"net/http"
+	"strconv"
 	"strings"
+	"testing"
+	"time"
 
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/client-go/kubernetes"
 
 	routev1 "github.com/openshift/client-go/route/clientset/versioned/typed/route/v1"
@@ -37,7 +42,7 @@ type PrometheusClient struct {
 	token string
 }
 
-// NewPrometheusClient returns creates and returns a new PrometheusClient.
+// NewPrometheusClient creates and returns a new PrometheusClient.
 func NewPrometheusClient(
 	routeClient routev1.RouteV1Interface,
 	kubeClient kubernetes.Interface,
@@ -68,8 +73,9 @@ func NewPrometheusClient(
 	}, nil
 }
 
-// Query makes a request against the Prometheus /api/v1/query endpoint.
-func (c *PrometheusClient) Query(query string) (int, error) {
+// Query runs an http get request against the Prometheus query api and returns
+// the response body.
+func (c *PrometheusClient) Query(query string) ([]byte, error) {
 	tr := &http.Transport{
 		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
 	}
@@ -78,7 +84,7 @@ func (c *PrometheusClient) Query(query string) (int, error) {
 
 	req, err := http.NewRequest("GET", "https://"+c.host+"/api/v1/query", nil)
 	if err != nil {
-		return 0, err
+		return nil, err
 	}
 
 	q := req.URL.Query()
@@ -89,21 +95,103 @@ func (c *PrometheusClient) Query(query string) (int, error) {
 
 	resp, err := client.Do(req)
 	if err != nil {
-		return 0, err
+		return nil, err
 	}
 
 	defer resp.Body.Close()
 
 	body, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
-		return 0, err
+		return nil, err
 	}
 
+	return body, nil
+}
+
+// GetFirstValueFromPromQuery takes a query api response body and returns the
+// value of the first timeseries. If body contains multiple timeseries
+// GetFirstValueFromPromQuery errors.
+func GetFirstValueFromPromQuery(body []byte) (int, error) {
 	res, err := gabs.ParseJSON(body)
 	if err != nil {
 		return 0, err
 	}
 
-	n, err := res.ArrayCountP("data.result")
-	return n, err
+	count, err := res.ArrayCountP("data.result")
+	if err != nil {
+		return 0, err
+	}
+
+	if count != 1 {
+		return 0, fmt.Errorf("expected body to contain single timeseries but got %v", count)
+	}
+
+	timeseries, err := res.ArrayElementP(0, "data.result")
+	if err != nil {
+		return 0, err
+	}
+
+	value, err := timeseries.ArrayElementP(1, "value")
+	if err != nil {
+		return 0, err
+	}
+
+	v, err := strconv.Atoi(value.Data().(string))
+	if err != nil {
+		return 0, fmt.Errorf("failed to parse query value: %v", err)
+	}
+
+	return v, nil
+}
+
+// WaitForQueryReturnGreaterEqualOne see WaitForQueryReturn.
+func (c *PrometheusClient) WaitForQueryReturnGreaterEqualOne(t *testing.T, timeout time.Duration, query string) {
+	c.WaitForQueryReturn(t, timeout, query, func(v int) error {
+		if v >= 1 {
+			return nil
+		}
+
+		return fmt.Errorf("expected value to equal or greater than 1 but got %v", v)
+	})
+}
+
+// WaitForQueryReturnOne see WaitForQueryReturn.
+func (c *PrometheusClient) WaitForQueryReturnOne(t *testing.T, timeout time.Duration, query string) {
+	c.WaitForQueryReturn(t, timeout, query, func(v int) error {
+		if v == 1 {
+			return nil
+		}
+
+		return fmt.Errorf("expected value to equal 1 but got %v", v)
+	})
+}
+
+// WaitForQueryReturn waits for a given PromQL query for a given time interval
+// and validates the **first and only** result with the given validate function.
+func (c *PrometheusClient) WaitForQueryReturn(t *testing.T, timeout time.Duration, query string, validate func(int) error) {
+	err := wait.Poll(5*time.Second, timeout, func() (bool, error) {
+		defer t.Log("---------------------------\n")
+		body, err := c.Query(query)
+		if err != nil {
+			return false, err
+		}
+
+		v, err := GetFirstValueFromPromQuery(body)
+		if err != nil {
+			t.Logf("failed to extract first value from query response for query %q: %v", query, err)
+			return false, nil
+		}
+
+		if err := validate(v); err != nil {
+			t.Logf("unexpected value for query %q: %v", query, err)
+			return false, nil
+		}
+
+		t.Logf("query %q succeeded", query)
+		return true, nil
+	})
+
+	if err != nil {
+		t.Fatal(err)
+	}
 }

test/e2e/framework/prometheus_client_test.go

@@ -0,0 +1,61 @@
+// Copyright 2019 The Cluster Monitoring 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 framework
+
+import (
+	"testing"
+)
+
+func TestGetFirstValueFromPromQuery(t *testing.T) {
+	tests := []struct {
+		Name string
+		F    func(t *testing.T)
+	}{
+		{
+			Name: "should fail on multiple timeseries",
+			F: func(t *testing.T) {
+				body := `
+{"status":"success","data":{"resultType":"vector","result":[{"metric":{"__name__":"ALERTS","alertname":"TargetDown","alertstate":"firing","job":"metrics","severity":"warning"},"value":[1551102571.196,"1"]},{"metric":{"__name__":"ALERTS","alertname":"Watchdog","alertstate":"firing","severity":"none"},"value":[1551102571.196,"1"]}]}}
+`
+
+				_, err := GetFirstValueFromPromQuery([]byte(body))
+				if err == nil || err.Error() != "expected body to contain single timeseries but got 2" {
+					t.Fatalf("expected GetFirstValueFromPromQuery to fail on multiple timeseries but got err %q instead", err)
+				}
+			},
+		},
+		{
+			Name: "should return first value",
+			F: func(t *testing.T) {
+				body := `
+{"status":"success","data":{"resultType":"vector","result":[{"metric":{"__name__":"ALERTS","alertname":"Watchdog","alertstate":"firing","severity":"none"},"value":[1551102571.196,"1"]}]}}
+`
+
+				v, err := GetFirstValueFromPromQuery([]byte(body))
+				if err != nil {
+					t.Fatal(err)
+				}
+
+				if v != 1 {
+					t.Fatalf("expected query to return %v but got %v", 1, v)
+				}
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.Name, test.F)
+	}
+}