[core] delay loading of NO_PROXY (Azure#14880)

until when ProxyPolicy is created

Author: jeremymeng

sdk/core/core-http/CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## 1.2.5 (Unreleased)
 
+- Delay loading of NO_PROXY environment variable until  when request pipeline is being created. This fixes [issue 14873](https://github.com/Azure/azure-sdk-for-js/issues/14873)
 
 ## 1.2.4 (2021-03-30)
 

sdk/core/core-http/src/policies/proxyPolicy.ts

@@ -17,7 +17,9 @@ import { getEnvironmentValue } from "../util/utils";
 /**
  * @internal
  */
-export const noProxyList: string[] = loadNoProxy();
+export const noProxyList: string[] = [];
+
+let noProxyListLoaded: boolean = false;
 const byPassedList: Map<string, boolean> = new Map();
 
 function loadEnvironmentProxyValue(): string | undefined {
@@ -70,6 +72,7 @@ function isBypassed(uri: string): boolean | undefined {
  */
 export function loadNoProxy(): string[] {
   const noProxy = getEnvironmentValue(Constants.NO_PROXY);
+  noProxyListLoaded = true;
   if (noProxy) {
     return noProxy
       .split(",")
@@ -103,6 +106,9 @@ export function proxyPolicy(proxySettings?: ProxySettings): RequestPolicyFactory
   if (!proxySettings) {
     proxySettings = getDefaultProxySettings();
   }
+  if (!noProxyListLoaded) {
+    noProxyList.push(...loadNoProxy());
+  }
   return {
     create: (nextPolicy: RequestPolicy, options: RequestPolicyOptions) => {
       return new ProxyPolicy(nextPolicy, options, proxySettings!);

sdk/core/core-rest-pipeline/CHANGELOG.md

@@ -2,9 +2,11 @@
 
 ## 1.1.0-beta.1 (Unreleased)
 
+- Rewrote `bearerTokenAuthenticationPolicy` to use a new backend that refreshes tokens only when they're about to expire and not multiple times before. This is based on a similar fix implemented on `@azure/core-http@1.2.4` ([PR with the changes](https://github.com/Azure/azure-sdk-for-js/pull/14223)). This fixes the issue: [13369](https://github.com/Azure/azure-sdk-for-js/issues/13369).
 - Add a new `bearerTokenChallengeAuthenticationPolicy` that provides a skeleton of handling challenge-based authorization. There are two extensible points: `authorizeRequest` and `authorizeRequestOnChallenge` callbacks.
   - `authorizeRequest` allows customizing the policy to alter how it authorizes a request before sending it. By default when no callbacks are specified, this policy has the same behavior as `bearerTokenAuthenticationPolicy`. It will retrieve the token from the underlying token credential, and if it gets one, it will cache the token and set it to the outgoing request.
   - `authorizeRequestOnChallenge`, which gets called only if we've found a challenge in the response. This callback has access to the original request and its response and is expected to handle the challenge. If this callback returns true, the request, usually updated after handling the challenge, will be sent again. If this call back returns false, no further actions will be taken.
+- Delay loading of NO_PROXY environment variable until when request pipeline is being created. This fixes [issue 14873](https://github.com/Azure/azure-sdk-for-js/issues/14873)
 
 ## 1.0.3 (2021-03-30)
 

sdk/core/core-rest-pipeline/src/policies/proxyPolicy.ts

@@ -25,7 +25,8 @@ const NO_PROXY = "NO_PROXY";
  */
 export const proxyPolicyName = "proxyPolicy";
 
-export const noProxyList: string[] = loadNoProxy();
+export const noProxyList: string[] = [];
+let noProxyListLoaded: boolean = false;
 const byPassedList: Map<string, boolean> = new Map();
 
 let httpsProxyAgent: https.Agent | undefined;
@@ -86,6 +87,7 @@ function isBypassed(uri: string): boolean | undefined {
 
 export function loadNoProxy(): string[] {
   const noProxy = getEnvironmentValue(NO_PROXY);
+  noProxyListLoaded = true;
   if (noProxy) {
     return noProxy
       .split(",")
@@ -175,6 +177,9 @@ function setProxyAgentOnRequest(request: PipelineRequest): void {
  * @param proxySettings - ProxySettings to use on each request.
  */
 export function proxyPolicy(proxySettings = getDefaultProxySettings()): PipelinePolicy {
+  if (!noProxyListLoaded) {
+    noProxyList.push(...loadNoProxy());
+  }
   return {
     name: proxyPolicyName,
     async sendRequest(request: PipelineRequest, next: SendRequest): Promise<PipelineResponse> {