[ARM] Deployment stacks What-If support

src/azure-cli-core/azure/cli/core/commandIndex.latest.json

@@ -212,8 +212,7 @@
       "azure.cli.command_modules.netappfiles"
     ],
     "network": [
-      "azure.cli.command_modules.network",
-      "azure.cli.command_modules.privatedns"
+      "azure.cli.command_modules.network"
     ],
     "policy": [
       "azure.cli.command_modules.policyinsights",
@@ -322,6 +321,9 @@
     "webapp": [
       "azure.cli.command_modules.appservice",
       "azure.cli.command_modules.serviceconnector"
+    ],
+    "stack-whatif": [
+      "azure.cli.command_modules.resource"
     ]
   }
 }

src/azure-cli-core/azure/cli/core/helpIndex.latest.json

@@ -366,6 +366,10 @@
       "webapp": {
         "summary": "Manage web apps.",
         "tags": ""
+      },
+      "stack-whatif": {
+        "summary": "A deployment stack What-If is a preview of an operation to be performed on a new or existing deployment stack.",
+        "tags": ""
       }
     },
     "commands": {

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

@@ -12,6 +12,7 @@ class Color(Enum):
     GREEN = "\033[38;5;77m"
     PURPLE = "\033[38;5;141m"
     BLUE = "\033[38;5;39m"
+    CYAN = "\033[38;5;51m"
     GRAY = "\033[38;5;246m"
     RED = "\033[38;5;203m"
     DARK_YELLOW = "\033[38;5;136m"
@@ -26,11 +27,15 @@ def __init__(self, enable_color=True):
         self._enable_color = enable_color
         self._contents = []
         self._colors = deque()
+        self._indents = []
 
     def build(self):
         return "".join(self._contents)
 
-    def append(self, value, color=None):
+    def append(self, value, color=None, no_indent=False):
+        if not no_indent and self._should_indent():
+            self._contents.append(''.join(self._indents))
+
         if color:
             self._push_color(color)
 
@@ -41,14 +46,57 @@ def append(self, value, color=None):
 
         return self
 
-    def append_line(self, value="", color=None):
-        self.append(f"{str(value)}\n", color)
-
-        return self
+    def append_line(self, value="", color=None, no_indent=False):
+        self.append(value, color, no_indent)
+        return self.append("\n", no_indent=True)
 
     def new_color_scope(self, color):
         return self.ColorScope(self, color)
 
+    def insert(self, index, value="", color=None, no_indent=False):
+        if color and self._enable_color:
+            self._contents.insert(index, str(Color.RESET))
+
+        self._contents.insert(index, str(value))
+
+        if color and self._enable_color:
+            self._contents.insert(index, str(color))
+
+        if not no_indent and self._should_indent(index, True):
+            self._contents.insert(index, ''.join(self._indents))
+
+        return self
+
+    def insert_line(self, index, value="", color=None, no_indent=False):
+        self.insert(index, "\n", no_indent=no_indent)
+        return self.insert(index, value, color, no_indent)
+
+    def get_current_index(self):
+        return len(self._contents)
+
+    def push_indent(self, indent):
+        self._indents.append(indent)
+
+    def pop_indent(self):
+        self._indents.pop()
+
+    def ensure_num_new_lines(self, num_new_lines):
+        if len(self._contents) == 0:
+            self.append("\n" * num_new_lines)
+            return
+
+        last_entry = self._contents[-1]
+        existing_newlines = len(last_entry) - len(last_entry.rstrip('\n'))
+        remaining_newlines = num_new_lines - existing_newlines
+
+        if remaining_newlines > 0:
+            self._contents.append("\n" * remaining_newlines)
+
+    def clear(self):
+        self._contents.clear()
+        self._colors.clear()
+        self._indents.clear()
+
     def _push_color(self, color):
         if not self._enable_color:
             return
@@ -63,6 +111,10 @@ def _pop_color(self):
         self._colors.pop()
         self._contents.append(str(self._colors[-1] if self._colors else Color.RESET))
 
+    def _should_indent(self, index=-1, is_insert=False):
+        return len(self._indents) > 0 and (
+            not self._contents or self._contents[max(index - 1, 0) if is_insert else index].endswith("\n"))
+
     # pylint: disable=protected-access
     class ColorScope:
         def __init__(self, color_string_builder, color):

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

@@ -3,14 +3,20 @@
 # Licensed under the MIT License. See License.txt in the project root for license information.
 # --------------------------------------------------------------------------------------------
 
+import typing as t
+import json
 from itertools import groupby
 
-from azure.mgmt.resource.deployments.models import ChangeType, PropertyChangeType, Level
+import azure.mgmt.resource.deployments.models as DeploymentModels
 
 from ._symbol import Symbol
 from ._color import Color, ColoredStringBuilder
 from ._utils import split_resource_id
 
+ChangeType = DeploymentModels.ChangeType
+PropertyChangeType = DeploymentModels.PropertyChangeType
+Level = DeploymentModels.Level
+
 _change_type_to_color = {
     ChangeType.create: Color.GREEN,
     ChangeType.delete: Color.ORANGE,
@@ -75,7 +81,10 @@
 }
 
 
-def format_what_if_operation_result(what_if_operation_result, enable_color=True):
+def format_what_if_operation_result(
+    what_if_operation_result: DeploymentModels.WhatIfOperationResult,
+    enable_color=True
+):
     builder = ColoredStringBuilder(enable_color)
     _format_noise_notice(builder)
     _format_change_type_legend(builder, what_if_operation_result.changes)
@@ -106,7 +115,7 @@ def _format_noise_notice(builder):
     builder.append_line()
 
 
-def _format_change_type_legend(builder, resource_changes):
+def _format_change_type_legend(builder, resource_changes: t.Optional[list[DeploymentModels.WhatIfChange]]):
     if not resource_changes:
         return
 
@@ -140,7 +149,11 @@ def populate_change_type_set(property_changes):
         builder.append_line(change_type.title())
 
 
-def _format_resource_changes_stats(builder, resource_changes, definite_changes=True):
+def _format_resource_changes_stats(
+    builder,
+    resource_changes: t.Optional[list[DeploymentModels.WhatIfChange]],
+    definite_changes=True
+):
     if definite_changes:
         builder.append_line().append("Resource changes: ")
 
@@ -208,7 +221,11 @@ def _format_diagnostics(builder, resource_changes, potential_changes, diagnostic
                 builder.append_line()
 
 
-def _format_resource_changes(builder, resource_changes, definite_changes=True):
+def _format_resource_changes(
+    builder,
+    resource_changes: t.Optional[list[DeploymentModels.WhatIfChange]],
+    definite_changes=True
+):
     if not resource_changes:
         return
 
@@ -245,9 +262,12 @@ def _format_resource_changes_in_scope(builder, scope, resource_changes_in_scope)
                 _format_resource_change(builder, resource_change, is_last)
 
 
-def _format_resource_change(builder, resource_change, is_last):
-    change_type = resource_change.change_type
+def _format_resource_change(builder, resource_change: DeploymentModels.WhatIfChange, is_last):
     relative_resource_id = _get_relative_resource_id(resource_change)
+    if relative_resource_id is None:
+        return
+
+    change_type = resource_change.change_type
     api_version = _get_api_version(resource_change)
 
     builder.append_line()
@@ -437,26 +457,33 @@ def _format_property_array_change(builder, parent_property_change, property_chan
     builder.append(Symbol.RIGHT_SQUARE_BRACKET)
 
 
-def _get_api_version(resource_change):
+def _get_api_version(resource_change: DeploymentModels.WhatIfChange):
     if resource_change.before:
         return resource_change.before.get("apiVersion")
     if resource_change.after:
         return resource_change.after.get("apiVersion")
     return None
 
 
-def _get_scope(resource_change):
-    scope, _ = split_resource_id(resource_change.resource_id)
-    return scope
+def _get_scope(resource_change: DeploymentModels.WhatIfChange):
+    if resource_change.resource_id:
+        return split_resource_id(resource_change.resource_id)[0]
+    if resource_change.extension:
+        # TODO: eventually this should include the extension config with key=value pairs
+        return f"{resource_change.extension.name}@{resource_change.extension.version}"
+    return "Unknown"
 
 
-def _get_scope_uppercase(resource_change):
+def _get_scope_uppercase(resource_change: DeploymentModels.WhatIfChange):
     return _get_scope(resource_change).upper()
 
 
-def _get_relative_resource_id(resource_change):
-    _, relative_resource_id = split_resource_id(resource_change.resource_id)
-    return relative_resource_id
+def _get_relative_resource_id(resource_change: DeploymentModels.WhatIfChange):
+    if resource_change.resource_id:
+        return split_resource_id(resource_change.resource_id)[1]
+    if resource_change.identifiers:
+        return _format_ext_resource_identifiers(resource_change.identifiers)
+    return None
 
 
 def _get_max_path_length_from_property_changes(property_changes):
@@ -639,3 +666,12 @@ def _is_non_empty_array(value):
 
 def _is_non_empty_object(value):
     return isinstance(value, dict) and value
+
+
+def _format_ext_resource_identifiers(identifiers: t.Optional[dict[str, t.Any]]) -> str:
+    if not identifiers:
+        return ""
+
+    sorted_items = sorted(identifiers.items(), key=lambda x: x[0])
+
+    return ", ".join(f"{key}={json.dumps(value)}" for key, value in sorted_items)