feat: introduce provider for signoz

Signed-off-by: Pranav <pranav10121@gmail.com>

Author: npv12

pkg/metrics/providers/factory.go

@@ -25,6 +25,8 @@ type Factory struct{}
 
 func (factory Factory) Provider(metricInterval string, provider flaggerv1.MetricTemplateProvider, credentials map[string][]byte, config *rest.Config) (Interface, error) {
 	switch provider.Type {
+	case "signoz":
+		return NewSignozProvider(provider, credentials)
 	case "prometheus":
 		return NewPrometheusProvider(provider, credentials)
 	case "datadog":

pkg/metrics/providers/signoz.go

@@ -0,0 +1,231 @@
+/*
+Copyright 2025 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"
+	"strconv"
+	"strings"
+	"time"
+
+	flaggerv1 "github.com/fluxcd/flagger/pkg/apis/flagger/v1beta1"
+)
+
+// SignozAPIPath is the default query range endpoint appended to the base address.
+var SignozAPIPath = "/api/v5/query_range"
+
+// SignozProvider executes SigNoz Query Range API requests
+type SignozProvider struct {
+	timeout   time.Duration
+	url       url.URL
+	headers   http.Header
+	client    *http.Client
+	queryPath string
+}
+
+// signozResponse models a flexible subset of SigNoz responses
+// It supports both single value and range values under common fields.
+type signozResponse struct {
+	Data struct {
+		Result []struct {
+			// Prometheus-like compatibility
+			Value  []interface{}   `json:"value"`
+			Values [][]interface{} `json:"values"`
+
+			// SigNoz series array
+			Series []struct {
+				Values [][]interface{} `json:"values"`
+			} `json:"series"`
+		} `json:"result"`
+	} `json:"data"`
+}
+
+// NewSignozProvider takes a provider spec and the credentials map,
+// validates the address, extracts the API key from the provided Secret,
+// and returns a client ready to execute requests against the SigNoz API.
+func NewSignozProvider(provider flaggerv1.MetricTemplateProvider, _ map[string][]byte) (*SignozProvider, error) {
+	signozURL, 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)
+	}
+
+	sp := SignozProvider{
+		timeout:   5 * time.Second,
+		url:       *signozURL,
+		headers:   provider.Headers,
+		client:    http.DefaultClient,
+		queryPath: SignozAPIPath,
+	}
+
+	if provider.InsecureSkipVerify {
+		t := http.DefaultTransport.(*http.Transport).Clone()
+		t.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
+		sp.client = &http.Client{Transport: t}
+	}
+
+	return &sp, nil
+}
+
+// RunQuery posts the provided JSON payload to SigNoz query_range and
+// returns a single float64 value derived from the response.
+//
+// Expectations:
+// - The input `query` is a valid JSON document per SigNoz Query Range API.
+// - The response must contain a single time series (or single value).
+// - Returns ErrMultipleValuesReturned when multiple series are found.
+// - Returns ErrNoValuesFound on missing/NaN values.
+func (p *SignozProvider) RunQuery(query string) (float64, error) {
+	u, err := url.Parse("." + p.queryPath)
+	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("POST", u.String(), io.NopCloser(strings.NewReader(query)))
+	if err != nil {
+		return 0, fmt.Errorf("http.NewRequest failed: %w", err)
+	}
+
+	if p.headers != nil {
+		req.Header = p.headers
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+	// No API key header expected; authentication is assumed unnecessary or handled externally.
+
+	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 r.StatusCode >= 400 {
+		return 0, fmt.Errorf("error response: %s", string(b))
+	}
+
+	var resp signozResponse
+	if err := json.Unmarshal(b, &resp); err != nil {
+		return 0, fmt.Errorf("error unmarshaling result: %w, '%s'", err, string(b))
+	}
+
+	// Determine the series to read from, ensuring single result
+	if len(resp.Data.Result) == 0 {
+		return 0, fmt.Errorf("%w", ErrNoValuesFound)
+	}
+	if len(resp.Data.Result) > 1 {
+		return 0, fmt.Errorf("%w", ErrMultipleValuesReturned)
+	}
+
+	result := resp.Data.Result[0]
+
+	// Prefer series[0].values if present (range response)
+	if len(result.Series) > 1 {
+		return 0, fmt.Errorf("%w", ErrMultipleValuesReturned)
+	}
+	if len(result.Series) == 1 {
+		vals := result.Series[0].Values
+		if len(vals) == 0 {
+			return 0, fmt.Errorf("%w", ErrNoValuesFound)
+		}
+		v, err := parseValue(vals[len(vals)-1])
+		if err != nil {
+			return 0, err
+		}
+		if math.IsNaN(v) {
+			return 0, fmt.Errorf("%w", ErrNoValuesFound)
+		}
+		return v, nil
+	}
+
+	// Fallback to values (matrix) or value (vector)-like structures
+	if len(result.Values) > 0 {
+		v, err := parseValue(result.Values[len(result.Values)-1])
+		if err != nil {
+			return 0, err
+		}
+		if math.IsNaN(v) {
+			return 0, fmt.Errorf("%w", ErrNoValuesFound)
+		}
+		return v, nil
+	}
+	if len(result.Value) == 2 {
+		switch val := result.Value[1].(type) {
+		case string:
+			f, err := strconv.ParseFloat(val, 64)
+			if err != nil {
+				return 0, err
+			}
+			if math.IsNaN(f) {
+				return 0, fmt.Errorf("%w", ErrNoValuesFound)
+			}
+			return f, nil
+		case float64:
+			if math.IsNaN(val) {
+				return 0, fmt.Errorf("%w", ErrNoValuesFound)
+			}
+			return val, nil
+		}
+	}
+
+	return 0, fmt.Errorf("%w", ErrNoValuesFound)
+}
+
+func parseValue(pair []interface{}) (float64, error) {
+	if len(pair) != 2 {
+		return 0, fmt.Errorf("invalid value pair")
+	}
+	switch v := pair[1].(type) {
+	case string:
+		return strconv.ParseFloat(v, 64)
+	case float64:
+		return v, nil
+	default:
+		return 0, fmt.Errorf("unsupported value type")
+	}
+}
+
+// IsOnline runs a minimal query and expects a value of 1
+func (p *SignozProvider) IsOnline() (bool, error) {
+	now := time.Now().UnixMilli()
+	body := fmt.Sprintf(`{"start": %d, "end": %d, "requestType": "time_series", "compositeQuery": {"queries": [{"type": "builder_formula", "spec": {"name": "F1", "expression": "1", "disabled": false}}]}}`, now-60000, now)
+
+	v, err := p.RunQuery(body)
+	if err != nil {
+		return false, fmt.Errorf("running query failed: %w", err)
+	}
+	if v != float64(1) {
+		return false, fmt.Errorf("value is not 1 for query: builder_formula 1")
+	}
+	return true, nil
+}