If proxying of the query fails - return 500.

proxy.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"crypto/tls"
+	"fmt"
 	"time"
 
 	fiber "github.com/gofiber/fiber/v2"
@@ -38,12 +39,19 @@ func proxyTheRequest(c *fiber.Ctx) error {
 
 	proxy.WithClient(cfg.Client.FastProxyClient)
 
+	cfg.Logger.Debug("Proxying the request", map[string]interface{}{"path": c.Path(), "body": string(c.Request().Body())})
 	err := proxy.DoRedirects(c, cfg.Server.HostGraphQL+c.Path(), 3)
 	if err != nil {
 		cfg.Logger.Error("Can't proxy the request", map[string]interface{}{"error": err.Error()})
 		cfg.Monitoring.Increment(libpack_monitoring.MetricsFailed, nil)
 		return err
 	}
+	cfg.Logger.Debug("Received proxied response", map[string]interface{}{"path": c.Path(), "response_body": string(c.Response().Body()), "response_code": c.Response().StatusCode()})
+
+	if c.Response().StatusCode() != 200 {
+		cfg.Monitoring.Increment(libpack_monitoring.MetricsFailed, nil)
+		return fmt.Errorf("Received non-200 response from the GraphQL server: %d", c.Response().StatusCode())
+	}
 
 	c.Response().Header.Del(fiber.HeaderServer)
 	return nil

server.go

@@ -127,7 +127,13 @@ func processGraphQLRequest(c *fiber.Ctx) error {
 
 // Additional helper function to avoid code repetition
 func proxyAndCacheTheRequest(c *fiber.Ctx, queryCacheHash string, cache_time int) {
-	proxyTheRequest(c)
+	err := proxyTheRequest(c)
+	if err != nil {
+		cfg.Logger.Error("Can't proxy the request", map[string]interface{}{"error": err.Error()})
+		cfg.Monitoring.Increment(libpack_monitoring.MetricsFailed, nil)
+		c.Status(500).SendString("Can't proxy the request - try again later")
+		return
+	}
 	cfg.Cache.CacheClient.Set(queryCacheHash, c.Response().Body(), time.Duration(cache_time)*time.Second)
 	c.Send(c.Response().Body())
 }