add additional observability when viewercontext user id is fetched

Summary:
From https://fburl.com/canvas/dw1end6w, it appears majority of requests actually do go through FB VC flow, but still doesn't explain why very few user ids were being propagated during the period where user id contextprop was fully rolled out.

Add additional ODS observability to check that `getUserId` is being resolved from VC

Reviewed By: aknott

Differential Revision: D69126070

fbshipit-source-id: 34c504e569430abb45a974e4f5057812757dedd8

thrift/lib/hack/src/ThriftContextPropState.php

@@ -107,32 +107,37 @@ public static function initFromString(?string $s)[defaults]: void {
   }
 
   public static function updateFromVC(?IViewerContextBase $vc): void {
-    $ods = CategorizedOBC::typedGet(ODSCategoryID::ODS_CONTEXTPROP);
     if ($vc is IFBViewerContext) {
       self::updateFBUserIdFromVC($vc);
-      $ods->bumpKey('contextprop.fb_vc');
     } else if ($vc is IIGViewerContext) {
       self::updateIGUserIdFromVC($vc);
-      $ods->bumpKey('contextprop.ig_vc');
     } else {
+      $ods = CategorizedOBC::typedGet(ODSCategoryID::ODS_CONTEXTPROP);
       $ods->bumpKey('contextprop.unknown_vc');
     }
   }
 
   private static function updateFBUserIdFromVC(IFBViewerContext $vc): void {
-    $tcps_fb_user_id = self::get()->getFBUserId();
+    $ods = CategorizedOBC::typedGet(ODSCategoryID::ODS_CONTEXTPROP);
+    $ods->bumpKey('contextprop.fb_vc');
     // don't overwrite if TCPS already has a valid fb user id
+    $tcps_fb_user_id = self::get()->getFBUserId();
     if (self::coerceId($tcps_fb_user_id) is nonnull) {
       return;
     }
 
     $fb_user_id = self::coerceId($vc->getUserID());
     if ($fb_user_id is nonnull) {
+      $ods->bumpKey('contextprop.set_fb_user_id');
       self::get()->setFBUserId($fb_user_id);
+    } else {
+      $ods->bumpKey('contextprop.missing_fb_user_id');
     }
   }
 
   private static function updateIGUserIdFromVC(IIGViewerContext $vc): void {
+    $ods = CategorizedOBC::typedGet(ODSCategoryID::ODS_CONTEXTPROP);
+    $ods->bumpKey('contextprop.ig_vc');
     // don't overwrite if TCPS already has a valid ig user id
     $tcps_ig_user_id = self::get()->getIGUserId();
     if (self::coerceId($tcps_ig_user_id) is nonnull) {
@@ -141,7 +146,10 @@ private static function updateIGUserIdFromVC(IIGViewerContext $vc): void {
 
     $ig_user_id = self::coerceId($vc->getViewerID());
     if ($ig_user_id is nonnull) {
+      $ods->bumpKey('contextprop.set_ig_user_id');
       self::get()->setIGUserId($ig_user_id);
+    } else {
+      $ods->bumpKey('contextprop.missing_ig_user_id');
     }
   }