chore(rename): move llama_stack.distribution to llama_stack.core (#2975)

We would like to rename the term `template` to `distribution`. To
prepare for that, this is a precursor.

cc @leseb

llama_stack/core/utils/exec.py

@@ -0,0 +1,143 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+import logging
+import os
+import signal
+import subprocess
+import sys
+
+from termcolor import cprint
+
+log = logging.getLogger(__name__)
+
+import importlib
+import json
+from pathlib import Path
+
+from llama_stack.core.utils.image_types import LlamaStackImageType
+
+
+def formulate_run_args(image_type: str, image_name: str) -> list[str]:
+    env_name = ""
+
+    if image_type == LlamaStackImageType.CONDA.value:
+        current_conda_env = os.environ.get("CONDA_DEFAULT_ENV")
+        env_name = image_name or current_conda_env
+        if not env_name:
+            cprint(
+                "No current conda environment detected, please specify a conda environment name with --image-name",
+                color="red",
+                file=sys.stderr,
+            )
+            return
+
+        def get_conda_prefix(env_name):
+            # Conda "base" environment does not end with "base" in the
+            # prefix, so should be handled separately.
+            if env_name == "base":
+                return os.environ.get("CONDA_PREFIX")
+            # Get conda environments info
+            conda_env_info = json.loads(subprocess.check_output(["conda", "info", "--envs", "--json"]).decode())
+            envs = conda_env_info["envs"]
+            for envpath in envs:
+                if os.path.basename(envpath) == env_name:
+                    return envpath
+            return None
+
+        cprint(f"Using conda environment: {env_name}", color="green", file=sys.stderr)
+        conda_prefix = get_conda_prefix(env_name)
+        if not conda_prefix:
+            cprint(
+                f"Conda environment {env_name} does not exist.",
+                color="red",
+                file=sys.stderr,
+            )
+            return
+
+        build_file = Path(conda_prefix) / "llamastack-build.yaml"
+        if not build_file.exists():
+            cprint(
+                f"Build file {build_file} does not exist.\n\nPlease run `llama stack build` or specify the correct conda environment name with --image-name",
+                color="red",
+                file=sys.stderr,
+            )
+            return
+    else:
+        # else must be venv since that is the only valid option left.
+        current_venv = os.environ.get("VIRTUAL_ENV")
+        env_name = image_name or current_venv
+        if not env_name:
+            cprint(
+                "No current virtual environment detected, please specify a virtual environment name with --image-name",
+                color="red",
+                file=sys.stderr,
+            )
+            return
+        cprint(f"Using virtual environment: {env_name}", file=sys.stderr)
+
+    script = importlib.resources.files("llama_stack") / "core/start_stack.sh"
+    run_args = [
+        script,
+        image_type,
+        env_name,
+    ]
+
+    return run_args
+
+
+def in_notebook():
+    try:
+        from IPython import get_ipython
+
+        if "IPKernelApp" not in get_ipython().config:  # pragma: no cover
+            return False
+    except ImportError:
+        return False
+    except AttributeError:
+        return False
+    return True
+
+
+def run_command(command: list[str]) -> int:
+    """
+    Run a command with interrupt handling and output capture.
+    Uses subprocess.run with direct stream piping for better performance.
+
+    Args:
+        command (list): The command to run.
+
+    Returns:
+        int: The return code of the command.
+    """
+    original_sigint = signal.getsignal(signal.SIGINT)
+    ctrl_c_pressed = False
+
+    def sigint_handler(signum, frame):
+        nonlocal ctrl_c_pressed
+        ctrl_c_pressed = True
+        log.info("\nCtrl-C detected. Aborting...")
+
+    try:
+        # Set up the signal handler
+        signal.signal(signal.SIGINT, sigint_handler)
+
+        # Run the command with stdout/stderr piped directly to system streams
+        result = subprocess.run(
+            command,
+            text=True,
+            check=False,
+        )
+        return result.returncode
+    except subprocess.SubprocessError as e:
+        log.error(f"Subprocess error: {e}")
+        return 1
+    except Exception as e:
+        log.exception(f"Unexpected error: {e}")
+        return 1
+    finally:
+        # Restore the original signal handler
+        signal.signal(signal.SIGINT, original_sigint)