allow --name to re-build from config

llama_stack/cli/stack/build.py

@@ -29,6 +29,26 @@ def available_templates_specs() -> List[BuildConfig]:
 
     return template_specs
 
+def get_build_config_from_name(name: str) -> Optional[Path]:
+    if os.getenv("CONDA_PREFIX", ""):
+        conda_dir = (
+            Path(os.getenv("CONDA_PREFIX")).parent / f"llamastack-{args.config}"
+        )
+    else:
+        cprint(
+            "Cannot find CONDA_PREFIX. Trying default conda path ~/.conda/envs...",
+            color="green",
+        )
+        conda_dir = (
+            Path(os.path.expanduser("~/.conda/envs")) / f"llamastack-{args.config}"
+        )
+
+    build_config_file = Path(conda_dir) / f"{args.config}-build.yaml"
+    if build_config_file.exists():
+        return build_config_file
+
+    return None
+
 
 class StackBuild(Subcommand):
     def __init__(self, subparsers: argparse._SubParsersAction):
@@ -189,6 +209,16 @@ class StackBuild(Subcommand):
 
             return
 
+        # try to see if we can find a pre-existing build config file through name
+        if args.name:
+            maybe_build_config = get_build_config_from_name(args.name)
+            if maybe_build_config:
+                print(f"Building from existing build config for {args.name} in {str(maybe_build_config)}")
+                with open(maybe_build_config, "r") as f:
+                    build_config = BuildConfig(**yaml.safe_load(f))
+                    self._run_stack_build_command_from_build_config(build_config)
+                    return
+
         if not args.config and not args.template:
             if not args.name:
                 name = prompt(