From 202a82afa03254f17e92d3d51d68ffb90473f2c8 Mon Sep 17 00:00:00 2001
From: Mahsa Soleimani <soleimanimahsa99@gmail.com>
Date: Tue, 23 Jan 2024 14:01:04 +0330
Subject: [PATCH] Monitoring client proxy (#5)

* Adding the proxy client code base + dockerfile

* Add the Helm chart for proxy client

* Delete workflows

* Changes on global variables,
metric type,
error handling, and channels for graceful shutdown

* Change checkProxy function to accept context,
Changes on ticker function

* Mostly change on ticker loop

* Final changes for client proxy

* Changes on checkproxy func client,
Add log for successMetric.Inc()

* Fix doecker image tag issue on image workflow

* Delete workflows

---------

Co-authored-by: Mahsa <mahsa.soleimani@snapp.cab>
---
 clients/proxy-client/main.go | 81 ++++++++++++++++++------------------
 1 file changed, 41 insertions(+), 40 deletions(-)

diff --git a/clients/proxy-client/main.go b/clients/proxy-client/main.go
index e8cb3bc..73dbcff 100644
--- a/clients/proxy-client/main.go
+++ b/clients/proxy-client/main.go
@@ -26,29 +26,33 @@ func init() {
 	prometheus.MustRegister(successMetric)
 }
 
-func checkProxy(ctx context.Context, proxyURL, targetURL string) error {
+func checkProxy(ctx context.Context, proxyURL, targetURL string) {
+	transport, _ := http.DefaultTransport.(*http.Transport)
+	transport.Proxy = http.ProxyURL(mustParseURL(proxyURL))
+
 	client := &http.Client{
-		Transport: &http.Transport{
-			Proxy: http.ProxyURL(mustParseURL(proxyURL)),
-		},
+		Transport: transport,
 	}
 
-	req, err := http.NewRequestWithContext(ctx, "HEAD", targetURL, nil)
+	req, err := http.NewRequestWithContext(ctx, "GET", targetURL, nil)
 	if err != nil {
-		return err
+		log.Printf("Error creating HTTP request: %s\n", err)
+		return
 	}
 
 	resp, err := client.Do(req)
 	if err != nil {
-		return err
+		log.Printf("Error performing HTTP request: %s\n", err)
+		return
 	}
 	defer resp.Body.Close()
 
 	if resp.StatusCode == http.StatusOK {
 		successMetric.Inc()
+		log.Printf("Proxy check succeed, Healthy status.")
+	} else {
+		log.Printf("Proxy check failed. Status code: %d\n", resp.StatusCode)
 	}
-
-	return nil
 }
 
 func mustParseURL(rawURL string) *url.URL {
@@ -67,16 +71,12 @@ func main() {
 	targetURL := "https://ifconfig.me"
 
 	http.Handle("/metrics", promhttp.Handler())
-	go func() {
-		err := http.ListenAndServe(":9090", nil)
-		if err != nil {
-			log.Printf("Error starting Prometheus HTTP server: %s\n", err)
-			os.Exit(1)
-		}
-	}()
+
+	server := &http.Server{
+		Addr: ":9090",
+	}
 
 	var wg sync.WaitGroup
-	wg.Add(1)
 
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
@@ -88,32 +88,33 @@ func main() {
 		<-signalCh
 		log.Println("Received signal, shutting down gracefully...")
 		cancel()
+		server.Shutdown(ctx)
 	}()
 
-	defer wg.Done()
-
-	defer func() {
-		log.Println("Waiting for all goroutines to finish...")
-		wg.Wait()
-		log.Println("All goroutines shut down. Exiting.")
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		ticker := time.NewTicker(5 * time.Minute)
+		defer ticker.Stop()
+
+		for {
+			select {
+			case <-ctx.Done():
+				log.Println("Ticker routine shutting down...")
+				return
+			case <-ticker.C:
+				checkProxy(ctx, proxyURL, targetURL)
+			}
+		}
 	}()
 
-	ticker := time.NewTicker(5 * time.Minute)
-	defer ticker.Stop()
-
-	tickerFunc := func() {
-		if err := checkProxy(ctx, proxyURL, targetURL); err != nil {
-			log.Printf("Proxy check failed: %s\n", err)
-		}
-	}
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		log.Fatal(server.ListenAndServe())
+	}()
 
-	for {
-		select {
-		case <-ctx.Done():
-			log.Println("Shutting down...")
-			return
-		case <-ticker.C:
-			tickerFunc()
-		}
-	}
+	log.Println("Waiting for the HTTP server to finish...")
+	wg.Wait()
+	log.Println("All goroutines shut down. Exiting.")
 }