Issue - 523 feat: Add configurable HTTP connection pooling for the adapter service

core/module/handler/stdHandler.go

@@ -28,6 +28,29 @@ type stdHandler struct {
 	publisher       definition.Publisher
 	SubscriberID    string
 	role            model.Role
+	httpClient      *http.Client
+}
+
+// newHTTPClient creates a new HTTP client with a custom transport configuration.
+func newHTTPClient(cfg *HttpClientConfig) *http.Client {
+	// Clone the default transport to inherit its sensible defaults.
+	transport := http.DefaultTransport.(*http.Transport).Clone()
+
+	// Only override the defaults if a value is explicitly provided in the config.
+	// A zero value in the config means we stick with the default values.
+	if cfg.MaxIdleConns > 0 {
+		transport.MaxIdleConns = cfg.MaxIdleConns
+	}
+	if cfg.MaxIdleConnsPerHost > 0 {
+		transport.MaxIdleConnsPerHost = cfg.MaxIdleConnsPerHost
+	}
+	if cfg.IdleConnTimeout > 0 {
+		transport.IdleConnTimeout = cfg.IdleConnTimeout
+	}
+	if cfg.ResponseHeaderTimeout > 0 {
+		transport.ResponseHeaderTimeout = cfg.ResponseHeaderTimeout
+	}
+	return &http.Client{Transport: transport}
 }
 
 // NewStdHandler initializes a new processor with plugins and steps.
@@ -36,6 +59,7 @@ func NewStdHandler(ctx context.Context, mgr PluginManager, cfg *Config) (http.Ha
 		steps:        []definition.Step{},
 		SubscriberID: cfg.SubscriberID,
 		role:         cfg.Role,
+		httpClient:   newHTTPClient(&cfg.HttpClientConfig),
 	}
 	// Initialize plugins.
 	if err := h.initPlugins(ctx, mgr, &cfg.Plugins); err != nil {
@@ -74,7 +98,7 @@ func (h *stdHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Handle routing based on the defined route type.
-	route(ctx, r, w, h.publisher)
+	route(ctx, r, w, h.publisher, h.httpClient)
 }
 
 // stepCtx creates a new StepContext for processing an HTTP request.
@@ -107,12 +131,12 @@ func (h *stdHandler) subID(ctx context.Context) string {
 var proxyFunc = proxy
 
 // route handles request forwarding or message publishing based on the routing type.
-func route(ctx *model.StepContext, r *http.Request, w http.ResponseWriter, pb definition.Publisher) {
+func route(ctx *model.StepContext, r *http.Request, w http.ResponseWriter, pb definition.Publisher, httpClient *http.Client) {
 	log.Debugf(ctx, "Routing to ctx.Route to %#v", ctx.Route)
 	switch ctx.Route.TargetType {
 	case "url":
 		log.Infof(ctx.Context, "Forwarding request to URL: %s", ctx.Route.URL)
-		proxyFunc(ctx, r, w)
+		proxyFunc(ctx, r, w, httpClient)
 		return
 	case "publisher":
 		if pb == nil {
@@ -136,7 +160,7 @@ func route(ctx *model.StepContext, r *http.Request, w http.ResponseWriter, pb de
 	}
 	response.SendAck(w)
 }
-func proxy(ctx *model.StepContext, r *http.Request, w http.ResponseWriter) {
+func proxy(ctx *model.StepContext, r *http.Request, w http.ResponseWriter, httpClient *http.Client) {
 	target := ctx.Route.URL
 	r.Header.Set("X-Forwarded-Host", r.Host)
 
@@ -147,7 +171,10 @@ func proxy(ctx *model.StepContext, r *http.Request, w http.ResponseWriter) {
 		log.Request(req.Context(), req, ctx.Body)
 	}
 
-	proxy := &httputil.ReverseProxy{Director: director}
+	proxy := &httputil.ReverseProxy{
+		Director:  director,
+		Transport: httpClient.Transport,
+	}
 
 	proxy.ServeHTTP(w, r)
 }