From d65bc40a8411a22e0600fcf1b9209dd472043312 Mon Sep 17 00:00:00 2001
From: George Fu <kuhe@users.noreply.github.com>
Date: Thu, 29 Aug 2024 16:48:07 +0000
Subject: [PATCH] fix(endpoints): resolve service-specific endpoint once per
 client

---
 .../src/adaptors/getEndpointFromConfig.ts            | 11 ++++++++++-
 .../src/adaptors/getEndpointFromInstructions.ts      |  3 ++-
 .../middleware-endpoint/src/resolveEndpointConfig.ts | 12 ++++++++++++
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/packages/middleware-endpoint/src/adaptors/getEndpointFromConfig.ts b/packages/middleware-endpoint/src/adaptors/getEndpointFromConfig.ts
index 903f66fbb21..7357a815a16 100644
--- a/packages/middleware-endpoint/src/adaptors/getEndpointFromConfig.ts
+++ b/packages/middleware-endpoint/src/adaptors/getEndpointFromConfig.ts
@@ -1,5 +1,14 @@
 import { loadConfig } from "@smithy/node-config-provider";
 
+import { EndpointResolvedConfig } from "../resolveEndpointConfig";
 import { getEndpointUrlConfig } from "./getEndpointUrlConfig";
 
-export const getEndpointFromConfig = async (serviceId: string) => loadConfig(getEndpointUrlConfig(serviceId))();
+/**
+ * @internal
+ */
+export const getEndpointFromConfig = async (config: Partial<EndpointResolvedConfig>) => {
+  if (config.serviceConfiguredEndpoint) {
+    return config.serviceConfiguredEndpoint;
+  }
+  return (config.serviceConfiguredEndpoint = await loadConfig(getEndpointUrlConfig(config.serviceId ?? ""))());
+};
diff --git a/packages/middleware-endpoint/src/adaptors/getEndpointFromInstructions.ts b/packages/middleware-endpoint/src/adaptors/getEndpointFromInstructions.ts
index 4e841c9a486..107a4a621a2 100644
--- a/packages/middleware-endpoint/src/adaptors/getEndpointFromInstructions.ts
+++ b/packages/middleware-endpoint/src/adaptors/getEndpointFromInstructions.ts
@@ -39,7 +39,8 @@ export const getEndpointFromInstructions = async <
   context?: HandlerExecutionContext
 ): Promise<EndpointV2> => {
   if (!clientConfig.endpoint) {
-    const endpointFromConfig = await getEndpointFromConfig(clientConfig.serviceId || "");
+    const endpointFromConfig = await getEndpointFromConfig(clientConfig);
+
     if (endpointFromConfig) {
       clientConfig.endpoint = () => Promise.resolve(toEndpointV1(endpointFromConfig));
     }
diff --git a/packages/middleware-endpoint/src/resolveEndpointConfig.ts b/packages/middleware-endpoint/src/resolveEndpointConfig.ts
index 3bbd3368527..f4bc37ee022 100644
--- a/packages/middleware-endpoint/src/resolveEndpointConfig.ts
+++ b/packages/middleware-endpoint/src/resolveEndpointConfig.ts
@@ -42,6 +42,12 @@ export interface EndpointInputConfig<T extends EndpointParameters = EndpointPara
    * Enables FIPS compatible endpoints.
    */
   useFipsEndpoint?: boolean | Provider<boolean>;
+
+  /**
+   * @internal
+   * This field is used internally so you should not fill any value to this field.
+   */
+  serviceConfiguredEndpoint?: never;
 }
 
 interface PreviouslyResolved<T extends EndpointParameters = EndpointParameters> {
@@ -95,6 +101,12 @@ export interface EndpointResolvedConfig<T extends EndpointParameters = EndpointP
    * @internal
    */
   serviceId?: string;
+
+  /**
+   * A configured endpoint global or specific to the service from ENV or AWS SDK configuration files.
+   * @internal
+   */
+  serviceConfiguredEndpoint?: string;
 }
 
 /**