Add --image and --entrypoint params to containerapp debug command

Allow customers to specify a custom container image and entrypoint
for the debug ephemeral container via 'az containerapp debug'.

- Add --image and --entrypoint optional parameters
- Append customDebugImageName and customDebugImageEntrypointCommand
  query params to the debug URL when provided
- Client-side validation: --entrypoint requires --image
- Add help examples for the new parameters

Author: khkh-ms

src/containerapp/azext_containerapp/_help.py

@@ -2447,6 +2447,12 @@
     - name: Debug by executing a command inside a container app and exit
       text: |
           az containerapp debug -n MyContainerapp -g MyResourceGroup --revision MyRevision --replica MyReplica --container MyContainer --command "echo Hello World"
+    - name: Debug with a custom container image
+      text: |
+          az containerapp debug -n MyContainerapp -g MyResourceGroup --container MyContainer --image mcr.microsoft.com/dotnet/sdk:8.0
+    - name: Debug with a custom container image and entrypoint
+      text: |
+          az containerapp debug -n MyContainerapp -g MyResourceGroup --container MyContainer --image mcr.microsoft.com/dotnet/sdk:8.0 --entrypoint /bin/bash
 """
 
 helps['containerapp label-history'] = """

src/containerapp/azext_containerapp/_params.py

@@ -515,6 +515,10 @@ def load_arguments(self, _):
                    help="The name of the container app revision. Default to the latest revision.")
         c.argument('name', name_type, id_part=None, help="The name of the Containerapp.")
         c.argument('resource_group_name', arg_type=resource_group_name_type, id_part=None)
+        c.argument('custom_debug_image_name', options_list=['--image'], is_preview=True,
+                   help="Custom container image for the debug ephemeral container (e.g., 'mcr.microsoft.com/dotnet/sdk:8.0'). If not specified, the platform default debug image is used.")
+        c.argument('custom_debug_image_entrypoint_command', options_list=['--entrypoint'], is_preview=True,
+                   help="Custom entrypoint command for the debug container (e.g., '/bin/bash'). Requires --image to also be specified.")
 
     with self.argument_context('containerapp label-history') as c:
         c.argument('resource_group_name', arg_type=resource_group_name_type, id_part=None)

src/containerapp/azext_containerapp/containerapp_debug_command_decorator.py

@@ -39,6 +39,12 @@ def get_argument_container_name(self):
     def get_argument_command(self):
         return self.get_param("command")
 
+    def get_argument_custom_debug_image_name(self):
+        return self.get_param("custom_debug_image_name")
+
+    def get_argument_custom_debug_image_entrypoint_command(self):
+        return self.get_param("custom_debug_image_entrypoint_command")
+
     def validate_arguments(self):
         validate_basic_arguments(
             resource_group_name=self.get_argument_resource_group_name(),
@@ -59,7 +65,7 @@ def _get_logstream_endpoint(self, cmd, resource_group_name, container_app_name,
             raise ValidationError(f"Error retrieving container in revision '{revision_name}' in the container app '{container_app_name}'.")
         return container_info[0]["logStreamEndpoint"]
 
-    def _get_url(self, cmd, resource_group_name, container_app_name, revision_name, replica_name, container_name, command):
+    def _get_url(self, cmd, resource_group_name, container_app_name, revision_name, replica_name, container_name, command, custom_debug_image_name=None, custom_debug_image_entrypoint_command=None):
         """Get the debug url for the specified container in the replica"""
         base_url = self._get_logstream_endpoint(cmd, resource_group_name, container_app_name, revision_name, replica_name, container_name)
         proxy_api_url = base_url[:base_url.index("/subscriptions/")]
@@ -68,6 +74,10 @@ def _get_url(self, cmd, resource_group_name, container_app_name, revision_name,
         debug_url = (f"{proxy_api_url}/subscriptions/{sub}/resourceGroups/{resource_group_name}/containerApps/{container_app_name}"
                      f"/revisions/{revision_name}/replicas/{replica_name}/debug"
                      f"?targetContainer={container_name}&command={encoded_cmd}")
+        if custom_debug_image_name:
+            debug_url += f"&customDebugImageName={urllib.parse.quote_plus(custom_debug_image_name)}"
+        if custom_debug_image_entrypoint_command:
+            debug_url += f"&customDebugImageEntrypointCommand={urllib.parse.quote_plus(custom_debug_image_entrypoint_command)}"
         return debug_url
 
     def _get_auth_token(self, cmd, resource_group_name, container_app_name):
@@ -82,7 +92,11 @@ def execute_Command(self, cmd):
         replica_name = self.get_argument_replica_name()
         container_name = self.get_argument_container_name()
         command = self.get_argument_command()
-        url = self._get_url(cmd, resource_group_name, container_app_name, revision_name, replica_name, container_name, command)
+        custom_debug_image_name = self.get_argument_custom_debug_image_name()
+        custom_debug_image_entrypoint_command = self.get_argument_custom_debug_image_entrypoint_command()
+        if custom_debug_image_entrypoint_command and not custom_debug_image_name:
+            raise ValidationError("--entrypoint requires --image to also be specified.")
+        url = self._get_url(cmd, resource_group_name, container_app_name, revision_name, replica_name, container_name, command, custom_debug_image_name, custom_debug_image_entrypoint_command)
         token = self._get_auth_token(cmd, resource_group_name, container_app_name)
         headers = [f"Authorization=Bearer {token}"]
         r = send_raw_request(cmd.cli_ctx, "GET", url, headers=headers)