Adding Chronosphere metrics provider

pkg/metrics/providers/chronosphere.go

@@ -0,0 +1,189 @@
+/*
+Copyright 2020 The Flux 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 providers
+
+import (
+	"context"
+	"crypto/tls"
+	"encoding/json"
+	"fmt"
+	"io"
+	"math"
+	"net/http"
+	"net/url"
+	"path"
+	"regexp"
+	"strconv"
+	"time"
+
+	flaggerv1 "github.com/fluxcd/flagger/pkg/apis/flagger/v1beta1"
+)
+
+const chronosphereOnlineQuery = "vector(1)"
+
+// ChronosphereProvider executes promQL queries
+type ChronosphereProvider struct {
+	timeout  time.Duration
+	url      url.URL
+	username string
+	password string
+	token    string
+	client   *http.Client
+}
+
+type chronosphereResponse struct {
+	Data struct {
+		Result []struct {
+			Metric struct {
+				Name string `json:"name"`
+			}
+			Value  []interface{} `json:"value"`
+			Values []interface{} `json:"values"`
+		}
+	}
+}
+
+// NewChronosphereProvider takes a provider spec and the credentials map,
+// validates the address, extracts the bearer token or username and password values if provided and
+// returns a Chronosphere client ready to execute queries against the API
+func NewChronosphereProvider(provider flaggerv1.MetricTemplateProvider, credentials map[string][]byte) (*ChronosphereProvider, error) {
+	promURL, err := url.Parse(provider.Address)
+	if provider.Address == "" || err != nil {
+		return nil, fmt.Errorf("%s address %s is not a valid URL", provider.Type, provider.Address)
+	}
+
+	prom := ChronosphereProvider{
+		timeout: 5 * time.Second,
+		url:     *promURL,
+		client:  http.DefaultClient,
+	}
+
+	if provider.InsecureSkipVerify {
+		t := http.DefaultTransport.(*http.Transport).Clone()
+		t.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
+		prom.client = &http.Client{Transport: t}
+	}
+
+	if provider.SecretRef != nil {
+		if token, ok := credentials["token"]; ok {
+			prom.token = string(token)
+		} else {
+
+			if username, ok := credentials["username"]; ok {
+				prom.username = string(username)
+			} else {
+				return nil, fmt.Errorf("%s credentials does not contain a username", provider.Type)
+			}
+
+			if password, ok := credentials["password"]; ok {
+				prom.password = string(password)
+			} else {
+				return nil, fmt.Errorf("%s credentials does not contain a password", provider.Type)
+			}
+		}
+	}
+
+	return &prom, nil
+}
+
+// RunQuery executes the promQL query and returns the the first result as float64
+func (p *ChronosphereProvider) RunQuery(query string) (float64, error) {
+	query = url.QueryEscape(p.trimQuery(query))
+	u, err := url.Parse(fmt.Sprintf("./data/metrics/api/v1/query?query=%s", query))
+	if err != nil {
+		return 0, fmt.Errorf("url.Parse failed: %w", err)
+	}
+	u.Path = path.Join(p.url.Path, u.Path)
+
+	u = p.url.ResolveReference(u)
+
+	req, err := http.NewRequest("GET", u.String(), nil)
+	if err != nil {
+		return 0, fmt.Errorf("http.NewRequest failed: %w", err)
+	}
+
+	if p.token != "" {
+		req.Header.Add("Authorization", "Bearer "+p.token)
+	} else if p.username != "" && p.password != "" {
+		req.SetBasicAuth(p.username, p.password)
+	}
+
+	ctx, cancel := context.WithTimeout(req.Context(), p.timeout)
+	defer cancel()
+
+	r, err := p.client.Do(req.WithContext(ctx))
+	if err != nil {
+		return 0, fmt.Errorf("request failed: %w", err)
+	}
+	defer r.Body.Close()
+
+	b, err := io.ReadAll(r.Body)
+	if err != nil {
+		return 0, fmt.Errorf("error reading body: %w", err)
+	}
+
+	if 400 <= r.StatusCode {
+		return 0, fmt.Errorf("error response: %s", string(b))
+	}
+
+	var result chronosphereResponse
+	err = json.Unmarshal(b, &result)
+	if err != nil {
+		return 0, fmt.Errorf("error unmarshaling result: %w, '%s'", err, string(b))
+	}
+
+	var value *float64
+	for _, v := range result.Data.Result {
+		if v.Values != nil {
+			return 0, fmt.Errorf("%w", ErrMultipleValuesReturned)
+		}
+		metricValue := v.Value[1]
+		switch metricValue.(type) {
+		case string:
+			f, err := strconv.ParseFloat(metricValue.(string), 64)
+			if err != nil {
+				return 0, err
+			}
+			value = &f
+		}
+	}
+	if value == nil || math.IsNaN(*value) {
+		return 0, fmt.Errorf("%w", ErrNoValuesFound)
+	}
+
+	return *value, nil
+}
+
+// IsOnline run simple Chronosphere query and returns an error if the API is unreachable
+func (p *ChronosphereProvider) IsOnline() (bool, error) {
+	value, err := p.RunQuery(chronosphereOnlineQuery)
+	if err != nil {
+		return false, fmt.Errorf("running query failed: %w", err)
+	}
+
+	if value != float64(1) {
+		return false, fmt.Errorf("value is not 1 for query: %s", chronosphereOnlineQuery)
+	}
+
+	return true, nil
+}
+
+// trimQuery takes a promql query and removes whitespace
+func (p *ChronosphereProvider) trimQuery(query string) string {
+	space := regexp.MustCompile(`\s+`)
+	return space.ReplaceAllString(query, " ")
+}