Refactoring project, adding BAN handling with X-Cache-Tags

app/Varnish/utils.go

@@ -0,0 +1,88 @@
+// Package varnish provides functions to build the list of varnish servers that will be used
+package varnish
+
+import (
+	"context"
+	"log"
+	"net/http"
+	"os"
+	"strings"
+
+	vault "http-broadcaster/Vault"
+)
+
+var (
+	varnishList = InitializeVarnishList()
+	status      = "200 Purged"
+)
+
+// 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), ",")
+	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"
+
+	// 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")
+		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)
+		}
+		resp, err := client.Do(req)
+		if err != nil {
+			log.Fatal("Send new request : ", err)
+		}
+		if resp.StatusCode != 200 {
+			status = "405 Not Allowed"
+		}
+	}
+	return status
+}