Remove cache control from meta data endpoint (#237)

* Remove cache control from meta data endpoint

* Run prettier

* Added a comment

packages/azure-kusto-data/src/cloudSettings.ts

@@ -39,7 +39,19 @@ export class CloudSettings {
         }
 
         try {
-            const response = await axios.get<{ AzureAD: CloudInfo | undefined }>(kustoUri + this.METADATA_ENDPOINT);
+            const response = await axios.get<{ AzureAD: CloudInfo | undefined }>(kustoUri + this.METADATA_ENDPOINT, {
+                headers: {
+                    "Cache-Control": "no-cache",
+                    // Disable caching - it's being cached in memory (Service returns max-age).
+                    // The original motivation for this is due to a CORS issue in Ibiza due to a dynamic subdomain.
+                    // The first dynamic subdomain is attached to the cache and for some reason isn't invalidated
+                    // when there is a new subdomain. It causes the request failure due to CORS.
+                    // Example:
+                    // Access to XMLHttpRequest at 'https://safrankecc.canadacentral.kusto.windows.net/v1/rest/auth/metadata' from origin
+                    // 'https://sandbox-46-11.reactblade.portal.azure.net' has been blocked by CORS policy: The 'Access-Control-Allow-Origin' header has a value
+                    // 'https://sandbox-46-10.reactblade.portal.azure.net' that is not equal to the supplied origin.
+                },
+            });
             if (response.status === 200) {
                 this.cloudCache[kustoUri] = response.data.AzureAD || this.defaultCloudInfo;
             } else {