Fix interface usage

Author: WoodProgrammer

cmd/prometheus.go

@@ -2,6 +2,7 @@ package cmd
 
 import (
 	"encoding/json"
+	"fmt"
 	"io/ioutil"
 	"net/http"
 	"os/exec"
@@ -12,15 +13,15 @@ import (
 type Prometheus interface {
 	FetchPrometheusData(url string) (int, map[string]interface{})
 	ImportPrometheusData(file, targetDir string) error
-	ExecutePromtoolCommand(args ...string) (string, error)
+	ExecutePromtoolCommand(sourceDir, targetDir string) (string, error)
 }
 
-type PromClient struct {
+type PromHandler struct {
 }
 
-func (promClient *PromClient) FetchPrometheusData(url string) (int, map[string]interface{}) {
+func (promHandler *PromHandler) FetchPrometheusData(url string) (int, map[string]interface{}) {
 	var metric map[string]interface{}
-
+	fmt.Println(url)
 	resp, err := http.Get(url)
 	if err != nil {
 		log.Err(err).Msg("Failed to fetch data")
@@ -42,17 +43,17 @@ func (promClient *PromClient) FetchPrometheusData(url string) (int, map[string]i
 	return resp.StatusCode, metric
 }
 
-func (promClient *PromClient) ImportPrometheusData(file, targetDir string) error {
-	result, err := promClient.ExecutePromtoolCommand(file, targetDir)
+func (promHandler *PromHandler) ImportPrometheusData(file, targetDir string) error {
+	result, err := promHandler.ExecutePromtoolCommand(file, targetDir)
 	if err != nil {
-		log.Err(err).Msg("Error on promClient.ExecutePromtoolCommand")
+		log.Err(err).Msg("Error on PromHandler.ExecutePromtoolCommand")
 		return err
 	}
 	log.Info().Msgf("Promtool command output is %s", result)
 	return nil
 }
 
-func (promClient *PromClient) ExecutePromtoolCommand(sourceDir, targetDir string) (string, error) {
+func (promHandler *PromHandler) ExecutePromtoolCommand(sourceDir, targetDir string) (string, error) {
 	cmd := exec.Command("promtool", "tsdb", "create-blocks-from", "openmetrics", sourceDir, targetDir)
 	output, err := cmd.CombinedOutput()
 	if err != nil {

go.mod

@@ -1,6 +1,6 @@
 module prom-migrator
 
-go 1.24.1
+go 1.24
 
 replace github.com/WoodProgrammer/prom-migrator/cmd => ./cmd
 

main.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"errors"
 	"fmt"
 	"os"
 	"strings"
@@ -27,36 +26,41 @@ var (
 	metricType   string
 )
 
+func newPrometheusHandler(host string) prom.Prometheus {
+	return &prom.PromHandler{}
+}
+
 func CallPrometheus() {
 
-	newPrometheusClient := prom.PromClient{}
+	var promHandler prom.Prometheus
+	promHandler = newPrometheusHandler(promHost)
 	rawMetricData := []string{}
 
 	if !strings.Contains(query, "\"") {
 		query = strings.ReplaceAll(query, "{", "{job=\"") // Example fix
 	}
 	url := fmt.Sprintf("http://%s:%s/api/v1/query_range?query=%s&start=%s&end=%s&step=%s",
 		promHost, promPort, query, startStamp, endStamp, step)
-	status, data := newPrometheusClient.FetchPrometheusData(url)
+	status, data := promHandler.FetchPrometheusData(url)
 
 	if status != 200 {
-		err := errors.New(fmt.Sprintf("un expected response from Prometheus server %d", status))
-		log.Err(err).Msg("Error while running newPrometheusClient.FetchPrometheusData")
+		err := fmt.Errorf("un expected response from Prometheus server %d", status)
+		log.Err(err).Msg("Error while running promHandler.FetchPrometheusData")
 		return
 	}
 	rawMetricData = append(rawMetricData, fmt.Sprintf("# TYPE %s %s", strings.Split(query, "{")[0], metricType))
 
 	parsedData, ok := data["data"].(map[string]interface{})
 
 	if !ok {
-		err := errors.New("json parsing error on rawPrometheus data ")
+		err := fmt.Errorf("json parsing error on rawPrometheus data ")
 		log.Err(err).Msg("Error parsing 'data'")
 		return
 	}
 
 	results, ok := parsedData["result"].([]interface{})
 	if !ok {
-		err := errors.New("json parsing error on parsedData['result'] data ")
+		err := fmt.Errorf("json parsing error on parsedData['result'] data ")
 		log.Err(err).Msg("Error parsing 'result'")
 		return
 	}
@@ -70,6 +74,9 @@ func CallPrometheus() {
 
 		labelMap := []string{}
 		metric, ok := result["metric"].(map[string]interface{})
+		if !ok {
+			continue
+		}
 		metricName, ok := metric["__name__"].(string)
 		if ok {
 			for key, value := range metric {
@@ -93,7 +100,7 @@ func CallPrometheus() {
 		}
 
 	}
-	rawMetricData = append(rawMetricData, fmt.Sprintf("# EOF"))
+	rawMetricData = append(rawMetricData, "# EOF")
 
 	err := ensureDir(dataDir)
 	if err != nil {
@@ -104,7 +111,7 @@ func CallPrometheus() {
 
 	if len(targetDir) != 0 {
 		cmd.FileHandler(fileName, rawMetricData)
-		newPrometheusClient.ImportPrometheusData(fileName, targetDir)
+		promHandler.ImportPrometheusData(fileName, targetDir)
 	}
 }