Moving to kube, refactoring code, using env variables only, adding metrics exporter

app/Varnish/utils.go

@@ -2,87 +2,63 @@
 package varnish
 
 import (
-	"context"
+	prometheus2 "http-broadcaster/Prometheus"
 	"log"
 	"net/http"
 	"os"
 	"strings"
-
-	vault "http-broadcaster/Vault"
+	"time"
 )
 
 var (
-	varnishList = InitializeVarnishList()
-	status      = "200 Purged"
+	// VarnishList contains the list of varnish servers.
+	VarnishList []string
+	status      = 200
 )
 
 // InitializeVarnishList sets varnishList variable according to the LIST_METHOD env var
-func InitializeVarnishList() []string {
-	switch method := os.Getenv("LIST_METHOD"); method {
-	case "vault":
-		return GetVarnishListFromVault()
-	case "file":
-		return GetVarnishListFromFile()
-	default:
-		panic("LIST_METHOD empty, no provided method to retrieve varnish list")
-	}
-}
-
-// GetVarnishListFromVault builds a list of varnish servers from Vault.
-func GetVarnishListFromVault() []string {
-	var value []string
-	client := vault.InitVaultConnection()
-	secret, err := client.KVv2("app").Get(context.Background(), "http-broadcaster/stg/envVars")
-	if err != nil {
-		log.Fatal("unable to read secret: %w", err)
-		return value
-	}
-
-	// selecting list key from retrieved secret
-	list, ok := secret.Data["varnish_list"].(string)
-	if !ok {
-		log.Fatal("value type assertion failed: %T %#v", secret.Data["varnish_list"], secret.Data["varnish_list"])
-		return value
-	}
-	value = strings.Split(string(list), ",")
-	return value
-}
-
-// GetVarnishListFromFile reads the list of varnish servers from a file on disk.
-func GetVarnishListFromFile() []string {
-	Data, err := os.ReadFile("./varnish")
-	if err != nil {
-		log.Fatal(err)
-	}
-	sliceData := strings.Split(string(Data), ",")
+func InitializeVarnishList(l string) []string {
+	data := os.Getenv("VARNISH_SERVERS")
+	sliceData := strings.Split(string(data), ",")
 	return sliceData
 }
 
 // SendToVarnish send to all varnish servers define in varnishList the request with the PURGE or BAN method
 // and the X-Cache-Tags header if necessary.
-func SendToVarnish(method string, url string, tag string) string {
-	status = "200 Purged"
+func SendToVarnish(method string, url string, tag map[string]string) int {
+	status = 200
 
 	// Take url to ban as argument.
 	// Loop over the list of Varnish servers and send PURGE request to each.
 	// Update status variable to check if servers have successfully purge url.
-	for i := 0; i < len(varnishList); i++ {
-		client := &http.Client{}
-		domain := strings.Trim(varnishList[i], "\r\n")
+	for i := 0; i < len(VarnishList); i++ {
+		client := &http.Client{
+			Timeout: 10 * time.Second,
+		}
+		// sanitize varnish server host.
+		domain := strings.Trim(VarnishList[i], "\r\n")
 		req, err := http.NewRequest(method, domain+url, nil)
 		if err != nil {
 			log.Fatal("Create new request : %s", err)
 		}
-		if tag != "" {
-			req.Header.Add("X-Cache-Tags", tag)
+		// If X-Cache-Tags header is not empty with pass it to varnish.
+		if tag["X-Cache-Tags"] != "" {
+			req.Header.Add("X-Cache-Tags", tag["X-Cache-Tags"])
+		}
+		if tag["ApiPlatform-Ban-Regex"] != "" {
+			req.Header.Add("ApiPlatform-Ban-Regex", tag["ApiPlatform-Ban-Regex"])
 		}
 		resp, err := client.Do(req)
 		if err != nil {
-			log.Fatal("Send new request : ", err)
+			log.Println("Send new request : ", err)
+		}
+		if prometheus2.MetricsEnabled {
+			prometheus2.IncrementBackendCounterVec(method)
 		}
 		if resp.StatusCode != 200 {
-			status = "405 Not Allowed"
+			status = 405
 		}
+		resp.Body.Close()
 	}
 	return status
 }