Statsbeat: rpId is not sent corectly for AppSvc Linux and Windows (#1739)

* Fix appsvc rpId

* Fix unit tests

Author: heyams

core/src/main/java/com/microsoft/applicationinsights/internal/statsbeat/AttachStatsbeat.java

@@ -31,9 +31,9 @@ class AttachStatsbeat extends BaseStatsbeat {
 
     private static final String UNKNOWN_RP_ID = "unknown";
 
-    private static final String WEBSITE_SITE_NAME = "appSrv_SiteName";
-    private static final String WEBSITE_HOSTNAME = "appSrv_wsHost";
-    private static final String WEBSITE_HOME_STAMPNAME = "appSrv_wsStamp";
+    private static final String WEBSITE_SITE_NAME = "WEBSITE_SITE_NAME";
+    private static final String WEBSITE_HOSTNAME = "WEBSITE_HOSTNAME";
+    private static final String WEBSITE_HOME_STAMPNAME = "WEBSITE_HOME_STAMPNAME";
 
     private volatile String resourceProviderId;
     private volatile MetadataInstanceResponse metadataInstanceResponse;
@@ -75,10 +75,11 @@ void updateMetadataInstance(MetadataInstanceResponse response) {
     static String initResourceProviderId(ResourceProvider resourceProvider, MetadataInstanceResponse response) {
         switch (resourceProvider) {
             case RP_APPSVC:
-                // FIXME (heya) Need to test these env vars on App Services Linux & Windows
-                return System.getenv(WEBSITE_SITE_NAME) + "/" + System.getenv(WEBSITE_HOME_STAMPNAME) + "/" + System.getenv(WEBSITE_HOSTNAME);
+                // Linux App Services doesn't have WEBSITE_HOME_STAMPNAME yet.
+                // TODO (heya) make a feature request for Linux App Services Team to support this.
+                return System.getenv(WEBSITE_SITE_NAME) + "/" + System.getenv(WEBSITE_HOME_STAMPNAME);
             case RP_FUNCTIONS:
-                return System.getenv("WEBSITE_HOSTNAME");
+                return System.getenv(WEBSITE_HOSTNAME);
             case RP_VM:
                 if (response != null) {
                     return response.getVmId() + "/" + response.getSubscriptionId();

core/src/test/java/com/microsoft/applicationinsights/internal/statsbeat/AttachStatsbeatTest.java

@@ -52,11 +52,10 @@ public void testVirtualMachineResourceProviderId() throws IOException {
 
     @Test
     public void testAppSvcResourceProviderId() {
-        envVars.set("appSrv_SiteName", "test_site_name");
-        envVars.set("appSrv_wsStamp", "test_stamp_name");
-        envVars.set("appSrv_wsHost", "test_hostname");
+        envVars.set("WEBSITE_SITE_NAME", "test_site_name");
+        envVars.set("WEBSITE_HOME_STAMPNAME", "test_stamp_name");
 
-        assertEquals("test_site_name/test_stamp_name/test_hostname", AttachStatsbeat.initResourceProviderId(ResourceProvider.RP_APPSVC, null));
+        assertEquals("test_site_name/test_stamp_name", AttachStatsbeat.initResourceProviderId(ResourceProvider.RP_APPSVC, null));
     }
 
     @Test