Templates: migrate clan templates to flake identifiers

pkgs/clan-cli/clan_lib/clan/create.py

@@ -4,16 +4,12 @@ from pathlib import Path
 
 from clan_lib.api import API
 from clan_lib.cmd import RunOpts, run
+from clan_lib.dirs import clan_templates
 from clan_lib.errors import ClanError
 from clan_lib.flake import Flake
 from clan_lib.nix import nix_command, nix_metadata, nix_shell
 from clan_lib.persist.inventory_store import InventorySnapshot, InventoryStore
-from clan_lib.templates import (
-    InputPrio,
-    TemplateName,
-    get_template,
-)
-from clan_lib.templates.filesystem import copy_from_nixstore
+from clan_lib.templates.handler import clan_template
 
 log = logging.getLogger(__name__)
 
@@ -21,9 +17,9 @@ log = logging.getLogger(__name__)
 @dataclass
 class CreateOptions:
     dest: Path
-    template_name: str
+    template: str
+
     src_flake: Flake | None = None
-    input_prio: InputPrio | None = None
     setup_git: bool = True
     initial: InventorySnapshot | None = None
     update_clan: bool = True
@@ -47,44 +43,31 @@ def create_clan(opts: CreateOptions) -> None:
             log.warning("Setting src_flake to None")
             opts.src_flake = None
 
-    template = get_template(
-        TemplateName(opts.template_name),
-        "clan",
-        input_prio=opts.input_prio,
-        clan_dir=opts.src_flake,
-    )
-    log.info(f"Found template '{template.name}' in '{template.input_variant}'")
+    if opts.src_flake is None:
+        opts.src_flake = Flake(str(clan_templates()))
 
-    if dest.exists():
-        dest /= template.name
+    with clan_template(
+        opts.src_flake, template_ident=opts.template, dst_dir=opts.dest
+    ) as _clan_dir:
+        if opts.setup_git:
+            run(git_command(dest, "init"))
+            run(git_command(dest, "add", "."))
 
-    if dest.exists():
-        msg = f"Destination directory {dest} already exists"
-        raise ClanError(msg)
+            # check if username is set
+            has_username = run(
+                git_command(dest, "config", "user.name"), RunOpts(check=False)
+            )
+            if has_username.returncode != 0:
+                run(git_command(dest, "config", "user.name", "clan-tool"))
 
-    src = Path(template.src["path"])
+            has_username = run(
+                git_command(dest, "config", "user.email"), RunOpts(check=False)
+            )
+            if has_username.returncode != 0:
+                run(git_command(dest, "config", "user.email", "clan@example.com"))
 
-    copy_from_nixstore(src, dest)
-
-    if opts.setup_git:
-        run(git_command(dest, "init"))
-        run(git_command(dest, "add", "."))
-
-        # check if username is set
-        has_username = run(
-            git_command(dest, "config", "user.name"), RunOpts(check=False)
-        )
-        if has_username.returncode != 0:
-            run(git_command(dest, "config", "user.name", "clan-tool"))
-
-        has_username = run(
-            git_command(dest, "config", "user.email"), RunOpts(check=False)
-        )
-        if has_username.returncode != 0:
-            run(git_command(dest, "config", "user.email", "clan@example.com"))
-
-    if opts.update_clan:
-        run(nix_command(["flake", "update"]), RunOpts(cwd=dest))
+        if opts.update_clan:
+            run(nix_command(["flake", "update"]), RunOpts(cwd=dest))
 
     if opts.initial:
         inventory_store = InventoryStore(flake=Flake(str(opts.dest)))

pkgs/clan-cli/clan_lib/templates/handler.py

@@ -99,3 +99,73 @@ def machine_template(
     finally:
         # If no error occurred, the machine directory is kept
         pass
+
+
+@contextmanager
+def clan_template(flake: Flake, template_ident: str, dst_dir: Path) -> Iterator[Path]:
+    """
+    Create a clan from a template.
+    This function will copy the template files to a new clan directory
+
+    :param flake: The flake to create the machine in.
+    :param template_ident: The identifier of the template to use. Example ".#template_name"
+    :param dst: The name of the directory to create.
+
+
+    Example usage:
+
+    >>> with clan_template(
+    ...     Flake("/home/johannes/git/clan-core"), ".#new-machine", "my-machine"
+    ... ) as clan_dir:
+    ...     # Use `clan_dir` here if you want to access the created directory
+
+    ... The directory is removed if the context raised any errors.
+    ... Only if the context is exited without errors, it is kept.
+    """
+
+    # Get the clan template from the specifier
+    [flake_ref, template_selector] = transform_url("clan", template_ident, flake=flake)
+    # For pretty error messages
+    printable_template_ref = f"{flake_ref}#{template_selector}"
+
+    template_flake = Flake(flake_ref)
+
+    try:
+        template = template_flake.select(template_selector)
+    except ClanError as e:
+        msg = f"Failed to select template '{template_ident}' from flake '{flake_ref}' (via attribute path: {printable_template_ref})"
+        raise ClanError(msg) from e
+
+    src = template.get("path")
+    if not src:
+        msg = f"Malformed template: {printable_template_ref} does not have a 'path' attribute"
+        raise ClanError(msg)
+
+    src_path = Path(src).resolve()
+
+    realize_nix_path(template_flake, str(src_path))
+
+    if not src_path.exists():
+        msg = f"Template {printable_template_ref} does not exist at {src_path}"
+        raise ClanError(msg)
+
+    if not src_path.is_dir():
+        msg = f"Template {printable_template_ref} is not a directory at {src_path}"
+        raise ClanError(msg)
+
+    if dst_dir.exists():
+        msg = f"Destination directory {dst_dir} already exists"
+        raise ClanError(msg)
+
+    copy_from_nixstore(src_path, dst_dir)
+
+    try:
+        yield dst_dir
+    except Exception as e:
+        log.error(f"An error occurred inside the 'clan_template' context: {e}")
+        log.info(f"Removing left-over directory: {dst_dir}")
+        shutil.rmtree(dst_dir, ignore_errors=True)
+        raise
+    finally:
+        # If no error occurred, the directory is kept
+        pass

pkgs/clan-cli/clan_lib/tests/test_create.py

@@ -137,7 +137,7 @@ def test_clan_create_api(
     # TODO: We need to generate a lock file for the templates
     clan_cli.clan.create.create_clan(
         clan_cli.clan.create.CreateOptions(
-            template_name="minimal", dest=dest_clan_dir, update_clan=False
+            template="minimal", dest=dest_clan_dir, update_clan=False
         )
     )
     assert dest_clan_dir.is_dir()