[ARM] az resource tag: Add parameter --is-incremental to support adding tags to resource incrementally (#12736)

src/azure-cli/azure/cli/command_modules/resource/_help.py

@@ -1712,6 +1712,9 @@
   - name: Tag a web app with the key 'vmlist' and value 'vm1', using a resource identifier.
     text: >
         az resource tag --tags vmlist=vm1 --ids /subscriptions/{SubID}/resourceGroups/{ResourceGroup}/providers/Microsoft.Web/sites/{WebApp}
+  - name: Tag the virtual machine 'MyVm' with the key 'vmlist' and value 'vm1' incrementally, it doesn't empty the existing tags.
+    text: >
+        az resource tag --tags vmlist=vm1 -g MyResourceGroup -n MyVm --resource-type "Microsoft.Compute/virtualMachines" -i
   - name: Tag a resource. (autogenerated)
     text: |
         az resource tag --ids /subscriptions/{SubID}/resourceGroups/{ResourceGroup}/providers/Microsoft.Web/sites/{WebApp} --tags vmlist=vm1

src/azure-cli/azure/cli/command_modules/resource/_params.py

@@ -93,6 +93,10 @@ def load_arguments(self, _):
         c.argument('scope', help='Fully-qualified scope for retrieving links.')
         c.argument('filter_string', options_list=['--filter', c.deprecate(target='--filter-string', redirect='--filter', hide=True)], help='Filter string for limiting results.')
 
+    with self.argument_context('resource tag') as c:
+        c.argument('is_incremental', action='store_true', options_list=['--is-incremental', '-i'],
+                   help='The option to add tags incrementally without deleting the original tags. If the key of new tag and original tag are duplicated, the original value will be overwritten.')
+
     with self.argument_context('provider') as c:
         c.ignore('top')
         c.argument('resource_provider_namespace', options_list=['--namespace', '-n'], completer=get_providers_completion_list, help=_PROVIDER_HELP_TEXT)

src/azure-cli/azure/cli/command_modules/resource/custom.py

@@ -1343,9 +1343,9 @@ def update_resource(cmd, parameters, resource_ids=None,
 
 
 # pylint: unused-argument
-def tag_resource(cmd, tags, resource_ids=None,
-                 resource_group_name=None, resource_provider_namespace=None,
-                 parent_resource_path=None, resource_type=None, resource_name=None, api_version=None):
+def tag_resource(cmd, tags, resource_ids=None, resource_group_name=None, resource_provider_namespace=None,
+                 parent_resource_path=None, resource_type=None, resource_name=None, api_version=None,
+                 is_incremental=None):
     """ Updates the tags on an existing resource. To clear tags, specify the --tag option
     without anything else. """
     parsed_ids = _get_parsed_resource_ids(resource_ids) or [_create_parsed_id(cmd.cli_ctx,
@@ -1356,7 +1356,8 @@ def tag_resource(cmd, tags, resource_ids=None,
                                                                               resource_name)]
 
     return _single_or_collection(
-        [_get_rsrc_util_from_parsed_id(cmd.cli_ctx, id_dict, api_version).tag(tags) for id_dict in parsed_ids])
+        [_get_rsrc_util_from_parsed_id(cmd.cli_ctx, id_dict, api_version).tag(tags, is_incremental)
+         for id_dict in parsed_ids])
 
 
 # pylint: unused-argument
@@ -2414,9 +2415,16 @@ def update(self, parameters):
                                                    self.api_version,
                                                    parameters)
 
-    def tag(self, tags):
+    def tag(self, tags, is_incremental=False):
         resource = self.get_resource()
 
+        if is_incremental is True:
+            if not tags:
+                raise CLIError("When modifying tag incrementally, the parameters of tag must have specific values.")
+            if resource.tags:
+                resource.tags.update(tags)
+                tags = resource.tags
+
         # please add the service type that needs to be requested with PATCH type here
         # for example: the properties of RecoveryServices/vaults must be filled, and a PUT request that passes back
         # to properties will fail due to the lack of properties, so the PATCH type should be used