Added commands with interactive prompts (#66)

If your command needs some terminal interactivity, simply add [`prompts:
Prompts` argument](#basic-terminal-user-interface-tui-primitives) to
your command:

```python
from databricks.sdk import WorkspaceClient
from databricks.labs.blueprint.entrypoint import get_logger
from databricks.labs.blueprint.cli import App
from databricks.labs.blueprint.tui import Prompts

app = App(__file__)
logger = get_logger(__file__)

@app.command
def me(w: WorkspaceClient, prompts: Prompts):
    """Shows current username"""
    if prompts.confirm("Are you sure?"):
        logger.info(f"Hello, {w.current_user.me().user_name}!")

if "__main__" == __name__:
    app()
```

Fix #49

README.md

@@ -50,6 +50,7 @@ Baseline for Databricks Labs projects written in Python. Sources are validated w
     * [Publishing Wheels to Databricks Workspace](#publishing-wheels-to-databricks-workspace)
   * [Databricks CLI's `databricks labs ...` Router](#databricks-clis-databricks-labs--router)
     * [Account-level Commands](#account-level-commands)
+    * [Commands with interactive prompts](#commands-with-interactive-prompts)
     * [Integration with Databricks Connect](#integration-with-databricks-connect)
     * [Starting New Projects](#starting-new-projects)
 * [Notable Downstream Projects](#notable-downstream-projects)
@@ -74,6 +75,8 @@ Your command-line apps do need testable interactivity, which is provided by `fro
 
 ![ucx install](docs/ucx-install.gif)
 
+It is also integrated with our [command router](#commands-with-interactive-prompts). 
+
 [[back to top](#databricks-labs-blueprint)]
 
 ### Simple Text Questions
@@ -1002,6 +1005,32 @@ def workspaces(a: AccountClient):
 
 [[back to top](#databricks-labs-blueprint)]
 
+### Commands with interactive prompts
+
+If your command needs some terminal interactivity, simply add [`prompts: Prompts` argument](#basic-terminal-user-interface-tui-primitives) to your command:
+
+```python
+from databricks.sdk import WorkspaceClient
+from databricks.labs.blueprint.entrypoint import get_logger
+from databricks.labs.blueprint.cli import App
+from databricks.labs.blueprint.tui import Prompts
+
+app = App(__file__)
+logger = get_logger(__file__)
+
+
+@app.command
+def me(w: WorkspaceClient, prompts: Prompts):
+    """Shows current username"""
+    if prompts.confirm("Are you sure?"):
+        logger.info(f"Hello, {w.current_user.me().user_name}!")
+
+if "__main__" == __name__:
+    app()
+```
+
+[[back to top](#databricks-labs-blueprint)]
+
 ### Integration with Databricks Connect
 
 Invoking Sparksession using Databricks Connect

src/databricks/labs/blueprint/cli.py

@@ -1,6 +1,7 @@
 """Baseline CLI for Databricks Labs projects."""
 
 import functools
+import inspect
 import json
 import logging
 from collections.abc import Callable
@@ -9,6 +10,7 @@
 from databricks.sdk import AccountClient, WorkspaceClient
 
 from databricks.labs.blueprint.entrypoint import get_logger, run_main
+from databricks.labs.blueprint.tui import Prompts
 from databricks.labs.blueprint.wheels import ProductInfo
 
 
@@ -27,6 +29,13 @@ def needs_workspace_client(self):
             return False
         return True
 
+    def prompts_argument_name(self) -> str | None:
+        sig = inspect.signature(self.fn)
+        for param in sig.parameters.values():
+            if param.annotation is Prompts:
+                return param.name
+        return None
+
 
 class App:
     def __init__(self, __file: str):
@@ -70,19 +79,33 @@ def _route(self, raw):
         databricks_logger.setLevel(log_level.upper())
         kwargs = {k.replace("-", "_"): v for k, v in flags.items()}
         try:
-            product_name = self._product_info.product_name()
-            product_version = self._product_info.version()
-            if self._mapping[command].needs_workspace_client():
-                kwargs["w"] = WorkspaceClient(product=product_name, product_version=product_version)
-            elif self._mapping[command].is_account:
-                kwargs["a"] = AccountClient(product=product_name, product_version=product_version)
-            self._mapping[command].fn(**kwargs)
+            cmd = self._mapping[command]
+            if cmd.needs_workspace_client():
+                kwargs["w"] = self._workspace_client()
+            elif cmd.is_account:
+                kwargs["a"] = self._account_client()
+            prompts_argument = cmd.prompts_argument_name()
+            if prompts_argument:
+                kwargs[prompts_argument] = Prompts()
+            cmd.fn(**kwargs)
         except Exception as err:  # pylint: disable=broad-exception-caught
             logger = self._logger.getChild(command)
             if log_level.lower() in {"debug", "trace"}:
                 logger.error(f"Failed to call {command}", exc_info=err)
             else:
                 logger.error(f"{err.__class__.__name__}: {err}")
 
+    def _account_client(self):
+        return AccountClient(
+            product=self._product_info.product_name(),
+            product_version=self._product_info.version(),
+        )
+
+    def _workspace_client(self):
+        return WorkspaceClient(
+            product=self._product_info.product_name(),
+            product_version=self._product_info.version(),
+        )
+
     def __call__(self):
         run_main(self._route)

tests/unit/test_cli.py

@@ -4,6 +4,17 @@
 from unittest import mock
 
 from databricks.labs.blueprint.cli import App
+from databricks.labs.blueprint.tui import Prompts
+
+FOO_COMMAND = json.dumps(
+    {
+        "command": "foo",
+        "flags": {
+            "name": "y",
+            "log_level": "disabled",
+        },
+    }
+)
 
 
 def test_commands():
@@ -15,22 +26,23 @@ def foo(name: str):
         """Some comment"""
         some(name)
 
-    with mock.patch.object(
-        sys,
-        "argv",
-        [
-            ...,
-            json.dumps(
-                {
-                    "command": "foo",
-                    "flags": {
-                        "name": "y",
-                        "log_level": "disabled",
-                    },
-                }
-            ),
-        ],
-    ):
+    with mock.patch.object(sys, "argv", [..., FOO_COMMAND]):
+        app()
+
+    some.assert_called_with("y")
+
+
+def test_injects_prompts():
+    some = mock.Mock()
+    app = App(inspect.getfile(App))
+
+    @app.command(is_unauthenticated=True)
+    def foo(name: str, prompts: Prompts):
+        """Some comment"""
+        assert isinstance(prompts, Prompts)
+        some(name)
+
+    with mock.patch.object(sys, "argv", [..., FOO_COMMAND]):
         app()
 
     some.assert_called_with("y")