refactor: Extract out stub_status scraper for external use

Author: motoki317

internal/ingress/metric/collectors/nginx_status.go

@@ -17,7 +17,7 @@ limitations under the License.
 package collectors
 
 import (
-"log"
+"fmt"
 "regexp"
 "strconv"
 
@@ -35,7 +35,10 @@ var (
 )
 
 type (
+NginxStatusScraper struct{}
+
 nginxStatusCollector struct {
+scraper NginxStatusScraper
 scrapeChan chan scrapeRequest
 
 data *nginxStatusData
@@ -47,7 +50,7 @@ type (
 connections *prometheus.Desc
 }
 
-basicStatus struct {
+NginxStubStatus struct {
 // Active total number of active connections
 Active int
 // Accepted total number of accepted client connections
@@ -65,6 +68,49 @@ type (
 }
 )
 
+func toInt(data []string, pos int) int {
+if len(data) == 0 {
+return 0
+}
+if pos > len(data) {
+return 0
+}
+if v, err := strconv.Atoi(data[pos]); err == nil {
+return v
+}
+return 0
+}
+
+func parse(data string) *NginxStubStatus {
+acr := ac.FindStringSubmatch(data)
+sahrr := sahr.FindStringSubmatch(data)
+readingr := reading.FindStringSubmatch(data)
+writingr := writing.FindStringSubmatch(data)
+waitingr := waiting.FindStringSubmatch(data)
+
+return &NginxStubStatus{
+toInt(acr, 1),
+toInt(sahrr, 1),
+toInt(sahrr, 2),
+toInt(sahrr, 3),
+toInt(readingr, 1),
+toInt(writingr, 1),
+toInt(waitingr, 1),
+}
+}
+
+func (s *NginxStatusScraper) Scrape() (*NginxStubStatus, error) {
+klog.V(3).InfoS("starting scraping socket", "path", nginx.StatusPath)
+status, data, err := nginx.NewGetStatusRequest(nginx.StatusPath)
+if err != nil {
+return nil, fmt.Errorf("obtaining nginx status info: %w", err)
+}
+if status < 200 || status >= 400 {
+return nil, fmt.Errorf("obtaining nginx status info (status %v)", status)
+}
+return parse(string(data)), nil
+}
+
 // NGINXStatusCollector defines a status collector interface
 type NGINXStatusCollector interface {
 prometheus.Collector
@@ -131,54 +177,14 @@ func (p nginxStatusCollector) Stop() {
 close(p.scrapeChan)
 }
 
-func toInt(data []string, pos int) int {
-if len(data) == 0 {
-return 0
-}
-if pos > len(data) {
-return 0
-}
-if v, err := strconv.Atoi(data[pos]); err == nil {
-return v
-}
-return 0
-}
-
-func parse(data string) *basicStatus {
-acr := ac.FindStringSubmatch(data)
-sahrr := sahr.FindStringSubmatch(data)
-readingr := reading.FindStringSubmatch(data)
-writingr := writing.FindStringSubmatch(data)
-waitingr := waiting.FindStringSubmatch(data)
-
-return &basicStatus{
-toInt(acr, 1),
-toInt(sahrr, 1),
-toInt(sahrr, 2),
-toInt(sahrr, 3),
-toInt(readingr, 1),
-toInt(writingr, 1),
-toInt(waitingr, 1),
-}
-}
-
 // nginxStatusCollector scrape the nginx status
 func (p nginxStatusCollector) scrape(ch chan<- prometheus.Metric) {
-klog.V(3).InfoS("starting scraping socket", "path", nginx.StatusPath)
-status, data, err := nginx.NewGetStatusRequest(nginx.StatusPath)
+s, err := p.scraper.Scrape()
 if err != nil {
-log.Printf("%v", err)
-klog.Warningf("unexpected error obtaining nginx status info: %v", err)
+klog.Warningf("failed to scrape nginx status: %v", err)
 return
 }
 
-if status < 200 || status >= 400 {
-klog.Warningf("unexpected error obtaining nginx status info (status %v)", status)
-return
-}
-
-s := parse(string(data))
-
 ch <- prometheus.MustNewConstMetric(p.data.connectionsTotal,
 prometheus.CounterValue, float64(s.Accepted), "accepted")
 ch <- prometheus.MustNewConstMetric(p.data.connectionsTotal,