handle delayed AAD resources in deployments (#585)

src/deployment/deploy.py

@@ -384,6 +384,13 @@ class Client:
                 mode=DeploymentMode.incremental, template=template, parameters=params
             )
         )
+        count = 0
+        tries = 10
+        error: Optional[Exception] = None
+        while count < tries:
+            count += 1
+
+            try:
                 result = client.deployments.create_or_update(
                     self.resource_group, gen_guid(), deployment
                 ).result()
@@ -394,6 +401,23 @@ class Client:
                     )
                     sys.exit(1)
                 self.results["deploy"] = result.properties.outputs
+                return
+            except Exception as err:
+                error = err
+                as_repr = repr(err)
+                # Modeled after Azure-CLI.  See:
+                # https://github.com/Azure/azure-cli/blob/
+                #   3a2f6009cff788fde3b0170823c9129f187b2812/src/azure-cli-core/
+                #   azure/cli/core/commands/arm.py#L1086
+                if (
+                    "PrincipalNotFound" in as_repr
+                    and "does not exist in the directory" in as_repr
+                ):
+                    logging.info("application principal not available in AAD yet")
+        if error:
+            raise error
+        else:
+            raise Exception("unknown error deploying")
 
     def assign_scaleset_identity_role(self) -> None:
         if self.upgrade:

src/deployment/registration.py

@@ -235,6 +235,14 @@ def add_application_password(app_object_id: UUID) -> Tuple[str, str]:
             return add_application_password_impl(app_object_id)
         except GraphQueryError as err:
             error = err
+            # modeled after AZ-CLI's handling of missing application
+            # See: https://github.com/Azure/azure-cli/blob/
+            #   e015d5bcba0c2d21dc42189daa43dc1eb82d2485/src/azure-cli/
+            #   azure/cli/command_modules/util/tests/
+            #   latest/test_rest.py#L191-L192
+            if "Request_ResourceNotFound" in repr(err):
+                logging.info("app unavailable in AAD, unable to create password yet")
+            else:
                 logging.warning("unable to create app password: %s", err.message)
         time.sleep(wait_duration)
     if error: