feat: add --run to llama stack build (#1156)

# What does this PR do?

--run runs the stack that was just build using the same arguments during
the build process (image-name, type, etc)

This simplifies the workflow a lot and makes the UX better for most
local users trying to get started rather than having to match the flags
of the two commands (build and then run)

Also, moved `ImageType` to distribution.utils since there were circular
import errors with its old location

## Test Plan

tested locally using the following command: 

`llama stack build --run --template ollama --image-type venv`

Signed-off-by: Charlie Doern <cdoern@redhat.com>

llama_stack/cli/stack/_build.py

@@ -23,10 +23,10 @@ from termcolor import cprint
 from llama_stack.cli.table import print_table
 from llama_stack.distribution.build import (
     SERVER_DEPENDENCIES,
-    ImageType,
     build_image,
     get_provider_dependencies,
 )
+from llama_stack.distribution.configure import parse_and_maybe_upgrade_config
 from llama_stack.distribution.datatypes import (
     BuildConfig,
     DistributionSpec,
@@ -37,7 +37,8 @@ from llama_stack.distribution.distribution import get_provider_registry
 from llama_stack.distribution.resolver import InvalidProviderError
 from llama_stack.distribution.utils.config_dirs import DISTRIBS_BASE_DIR
 from llama_stack.distribution.utils.dynamic import instantiate_class_type
-from llama_stack.distribution.utils.exec import in_notebook
+from llama_stack.distribution.utils.exec import formulate_run_args, in_notebook, run_with_pty
+from llama_stack.distribution.utils.image_types import ImageType
 from llama_stack.providers.datatypes import Api
 
 TEMPLATES_PATH = Path(__file__).parent.parent.parent / "templates"
@@ -186,19 +187,41 @@ def run_stack_build_command(args: argparse.Namespace) -> None:
             print(f"uv pip install {special_dep}")
         return
 
-    _run_stack_build_command_from_build_config(
-        build_config,
-        image_name=image_name,
-        config_path=args.config,
-        template_name=args.template,
-    )
+    try:
+        run_config = _run_stack_build_command_from_build_config(
+            build_config,
+            image_name=image_name,
+            config_path=args.config,
+            template_name=args.template,
+        )
+
+    except Exception as exc:
+        cprint(
+            f"Error building stack: {exc}",
+            color="red",
+        )
+        return
+    if run_config is None:
+        cprint(
+            "Run config path is empty",
+            color="red",
+        )
+        return
+
+    if args.run:
+        run_config = Path(run_config)
+        config_dict = yaml.safe_load(run_config.read_text())
+        config = parse_and_maybe_upgrade_config(config_dict)
+        run_args = formulate_run_args(args.image_type, args.image_name, config, args.template)
+        run_args.extend([run_config, str(os.getenv("LLAMA_STACK_PORT", 8321))])
+        run_with_pty(run_args)
 
 
 def _generate_run_config(
     build_config: BuildConfig,
     build_dir: Path,
     image_name: str,
-) -> None:
+) -> str:
     """
     Generate a run.yaml template file for user to edit from a build.yaml file
     """
@@ -248,6 +271,7 @@ def _generate_run_config(
         f"You can now run your stack with `llama stack run {run_config_file}`",
         color="green",
     )
+    return run_config_file
 
 
 def _run_stack_build_command_from_build_config(
@@ -255,7 +279,7 @@ def _run_stack_build_command_from_build_config(
     image_name: Optional[str] = None,
     template_name: Optional[str] = None,
     config_path: Optional[str] = None,
-) -> None:
+) -> str:
     if build_config.image_type == ImageType.container.value:
         if template_name:
             image_name = f"distribution-{template_name}"
@@ -298,8 +322,9 @@ def _run_stack_build_command_from_build_config(
             shutil.copy(path, run_config_file)
 
         cprint("Build Successful!", color="green")
+        return template_path
     else:
-        _generate_run_config(build_config, build_dir, image_name)
+        return _generate_run_config(build_config, build_dir, image_name)
 
 
 def _run_template_list_cmd() -> None: