Reuse http client and add retry to the proxied requests.

proxy.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/avast/retry-go/v4"
 	fiber "github.com/gofiber/fiber/v2"
 	"github.com/gofiber/fiber/v2/middleware/proxy"
 	libpack_monitoring "github.com/lukaszraczylo/graphql-monitoring-proxy/monitoring"
@@ -40,12 +41,31 @@ func proxyTheRequest(c *fiber.Ctx) error {
 	c.Request().Header.Del(fiber.HeaderAcceptEncoding)
 
 	cfg.Logger.Debug("Proxying the request", map[string]interface{}{"path": c.Path(), "body": string(c.Request().Body()), "headers": c.GetReqHeaders(), "request_uuid": c.Locals("request_uuid")})
+
+	err := retry.Do(
+		func() error {
 			err := proxy.DoRedirects(c, cfg.Server.HostGraphQL+c.Path(), 3, cfg.Client.FastProxyClient)
 			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
 			}
+			return nil
+		},
+		retry.OnRetry(func(n uint, err error) {
+			cfg.Logger.Warning("Retrying the request", map[string]interface{}{"path": c.Path(), "error": err.Error()})
+		}),
+		retry.Attempts(uint(3)),
+		retry.DelayType(retry.BackOffDelay),
+		retry.Delay(time.Duration(250*time.Millisecond)),
+		retry.LastErrorOnly(true),
+	)
+
+	if err != nil {
+		cfg.Logger.Warning("Can't proxy the request", map[string]interface{}{"error": err.Error()})
+		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(), "headers": c.GetRespHeaders(), "request_uuid": c.Locals("request_uuid")})
 
 	if c.Response().StatusCode() != 200 {