make host key check an enum instead of an literal type

this is more typesafe at runtime.

pkgs/clan-cli/clan_cli/host_key_check.py

@@ -0,0 +1,28 @@
+"""Common argument types and utilities for host key checking in clan CLI commands."""
+
+import argparse
+
+from clan_lib.ssh.host_key import HostKeyCheck
+
+
+def host_key_check_type(value: str) -> HostKeyCheck:
+    """
+    Argparse type converter for HostKeyCheck enum.
+    """
+    try:
+        return HostKeyCheck(value)
+    except ValueError:
+        valid_values = [e.value for e in HostKeyCheck]
+        msg = f"Invalid host key check mode: {value}. Valid options: {', '.join(valid_values)}"
+        raise argparse.ArgumentTypeError(msg) from None
+
+
+def add_host_key_check_arg(
+    parser: argparse.ArgumentParser, default: HostKeyCheck = HostKeyCheck.ASK
+) -> None:
+    parser.add_argument(
+        "--host-key-check",
+        type=host_key_check_type,
+        default=default,
+        help=f"Host key (.ssh/known_hosts) check mode. Options: {', '.join([e.value for e in HostKeyCheck])}",
+    )

pkgs/clan-cli/clan_cli/machines/hardware.py

@@ -12,6 +12,7 @@ from clan_lib.machines.suggestions import validate_machine_names
 from clan_lib.ssh.remote import Remote
 
 from clan_cli.completions import add_dynamic_completer, complete_machines
+from clan_cli.host_key_check import add_host_key_check_arg
 
 from .types import machine_name_type
 
@@ -54,12 +55,7 @@ def register_update_hardware_config(parser: argparse.ArgumentParser) -> None:
         nargs="?",
         help="ssh address to install to in the form of user@host:2222",
     )
-    parser.add_argument(
-        "--host-key-check",
-        choices=["strict", "ask", "tofu", "none"],
-        default="ask",
-        help="Host key (.ssh/known_hosts) check mode.",
-    )
+    add_host_key_check_arg(parser)
     parser.add_argument(
         "--password",
         help="Pre-provided password the cli will prompt otherwise if needed.",

pkgs/clan-cli/clan_cli/machines/install.py

@@ -13,6 +13,7 @@ from clan_cli.completions import (
     complete_machines,
     complete_target_host,
 )
+from clan_cli.host_key_check import add_host_key_check_arg
 from clan_cli.machines.hardware import HardwareConfig
 from clan_cli.ssh.deploy_info import DeployInfo, find_reachable_host, ssh_command_parse
 
@@ -97,12 +98,7 @@ def register_install_parser(parser: argparse.ArgumentParser) -> None:
         help="do not reboot after installation (deprecated)",
         default=False,
     )
-    parser.add_argument(
-        "--host-key-check",
-        choices=["strict", "ask", "tofu", "none"],
-        default="ask",
-        help="Host key (.ssh/known_hosts) check mode.",
-    )
+    add_host_key_check_arg(parser)
     parser.add_argument(
         "--build-on",
         choices=[x.value for x in BuildOn],

pkgs/clan-cli/clan_cli/machines/update.py

@@ -16,6 +16,7 @@ from clan_cli.completions import (
     complete_machines,
     complete_tags,
 )
+from clan_cli.host_key_check import add_host_key_check_arg
 
 log = logging.getLogger(__name__)
 
@@ -163,12 +164,7 @@ def register_update_parser(parser: argparse.ArgumentParser) -> None:
     )
     add_dynamic_completer(tag_parser, complete_tags)
 
-    parser.add_argument(
-        "--host-key-check",
-        choices=["strict", "ask", "tofu", "none"],
-        default="ask",
-        help="Host key (.ssh/known_hosts) check mode.",
-    )
+    add_host_key_check_arg(parser)
     parser.add_argument(
         "--target-host",
         type=str,

pkgs/clan-cli/clan_cli/ssh/deploy_info.py

@@ -8,12 +8,14 @@ from typing import Any
 from clan_lib.cmd import run
 from clan_lib.errors import ClanError
 from clan_lib.nix import nix_shell
-from clan_lib.ssh.remote import HostKeyCheck, Remote
+from clan_lib.ssh.host_key import HostKeyCheck
+from clan_lib.ssh.remote import Remote
 
 from clan_cli.completions import (
     add_dynamic_completer,
     complete_machines,
 )
+from clan_cli.host_key_check import add_host_key_check_arg
 from clan_cli.ssh.tor import TorTarget, spawn_tor, ssh_tor_reachable
 
 log = logging.getLogger(__name__)
@@ -181,10 +183,5 @@ def register_parser(parser: argparse.ArgumentParser) -> None:
         "--png",
         help="specify the json file for ssh data as the qrcode image (generated by starting the clan installer)",
     )
-    parser.add_argument(
-        "--host-key-check",
-        choices=["strict", "ask", "tofu", "none"],
-        default="tofu",
-        help="Host key (.ssh/known_hosts) check mode.",
-    )
+    add_host_key_check_arg(parser, default=HostKeyCheck.TOFU)
     parser.set_defaults(func=ssh_command)

pkgs/clan-cli/clan_cli/ssh/test_deploy_info.py

@@ -4,6 +4,7 @@ from pathlib import Path
 import pytest
 from clan_lib.cmd import RunOpts, run
 from clan_lib.nix import nix_shell
+from clan_lib.ssh.host_key import HostKeyCheck
 from clan_lib.ssh.remote import Remote
 
 from clan_cli.ssh.deploy_info import DeployInfo, find_reachable_host
@@ -23,7 +24,7 @@ def test_qrcode_scan(temp_dir: Path) -> None:
     run(cmd, RunOpts(input=data.encode()))
 
     # Call the qrcode_scan function
-    deploy_info = DeployInfo.from_qr_code(img_path, "none")
+    deploy_info = DeployInfo.from_qr_code(img_path, HostKeyCheck.NONE)
 
     host = deploy_info.addrs[0]
     assert host.address == "192.168.122.86"
@@ -46,7 +47,7 @@ def test_qrcode_scan(temp_dir: Path) -> None:
 
 def test_from_json() -> None:
     data = '{"pass":"scabbed-defender-headlock","tor":"qjeerm4r6t55hcfum4pinnvscn5njlw2g3k7ilqfuu7cdt3ahaxhsbid.onion","addrs":["192.168.122.86"]}'
-    deploy_info = DeployInfo.from_json(json.loads(data), "none")
+    deploy_info = DeployInfo.from_json(json.loads(data), HostKeyCheck.NONE)
 
     host = deploy_info.addrs[0]
     assert host.password == "scabbed-defender-headlock"
@@ -69,7 +70,9 @@ def test_from_json() -> None:
 @pytest.mark.with_core
 def test_find_reachable_host(hosts: list[Remote]) -> None:
     host = hosts[0]
-    deploy_info = DeployInfo.from_hostnames(["172.19.1.2", host.ssh_url()], "none")
+    deploy_info = DeployInfo.from_hostnames(
+        ["172.19.1.2", host.ssh_url()], HostKeyCheck.NONE
+    )
 
     assert deploy_info.addrs[0].address == "172.19.1.2"
 

pkgs/clan-cli/clan_cli/tests/hosts.py

@@ -4,6 +4,7 @@ from pathlib import Path
 
 import pytest
 from clan_cli.tests.sshd import Sshd
+from clan_lib.ssh.host_key import HostKeyCheck
 from clan_lib.ssh.remote import Remote
 
 
@@ -16,7 +17,7 @@ def hosts(sshd: Sshd) -> list[Remote]:
             port=sshd.port,
             user=login,
             private_key=Path(sshd.key),
-            host_key_check="none",
+            host_key_check=HostKeyCheck.NONE,
             command_prefix="local_test",
         )
     ]

pkgs/clan-cli/clan_lib/ssh/host_key.py

@@ -1,15 +1,15 @@
 # Adapted from https://github.com/numtide/deploykit
 
-from typing import Literal
+from enum import Enum
 
 from clan_lib.errors import ClanError
 
-HostKeyCheck = Literal[
-    "strict",  # Strictly check ssh host keys, prompt for unknown ones
-    "ask",  # Ask for confirmation on first use
-    "tofu",  # Trust on ssh keys on first use
-    "none",  # Do not check ssh host keys
-]
+
+class HostKeyCheck(Enum):
+    STRICT = "strict"  # Strictly check ssh host keys, prompt for unknown ones
+    ASK = "ask"  # Ask for confirmation on first use
+    TOFU = "tofu"  # Trust on ssh keys on first use
+    NONE = "none"  # Do not check ssh host keys
 
 
 def hostkey_to_ssh_opts(host_key_check: HostKeyCheck) -> list[str]:
@@ -17,13 +17,13 @@ def hostkey_to_ssh_opts(host_key_check: HostKeyCheck) -> list[str]:
     Convert a HostKeyCheck value to SSH options.
     """
     match host_key_check:
-        case "strict":
+        case HostKeyCheck.STRICT:
             return ["-o", "StrictHostKeyChecking=yes"]
-        case "ask":
+        case HostKeyCheck.ASK:
             return []
-        case "tofu":
+        case HostKeyCheck.TOFU:
             return ["-o", "StrictHostKeyChecking=accept-new"]
-        case "none":
+        case HostKeyCheck.NONE:
             return [
                 "-o",
                 "StrictHostKeyChecking=no",

pkgs/clan-cli/clan_lib/ssh/remote.py

@@ -39,7 +39,7 @@ class Remote:
     private_key: Path | None = None
     password: str | None = None
     forward_agent: bool = True
-    host_key_check: HostKeyCheck = "ask"
+    host_key_check: HostKeyCheck = HostKeyCheck.ASK
     verbose_ssh: bool = False
     ssh_options: dict[str, str] = field(default_factory=dict)
     tor_socks: bool = False

pkgs/clan-cli/clan_lib/ssh/remote_test.py

@@ -9,6 +9,7 @@ from clan_lib.async_run import AsyncRuntime
 from clan_lib.cmd import ClanCmdTimeoutError, Log, RunOpts
 from clan_lib.errors import ClanError, CmdOut
 from clan_lib.ssh.remote import Remote
+from clan_lib.ssh.host_key import HostKeyCheck
 from clan_lib.ssh.sudo_askpass_proxy import SudoAskpassProxy
 
 if sys.platform == "darwin":
@@ -113,7 +114,7 @@ def test_parse_deployment_address(
         result = Remote.from_ssh_uri(
             machine_name=machine_name,
             address=test_addr,
-        ).override(host_key_check="strict")
+        ).override(host_key_check=HostKeyCheck.STRICT)
 
     if expected_exception:
         return
@@ -131,7 +132,7 @@ def test_parse_deployment_address(
 def test_parse_ssh_options() -> None:
     addr = "root@example.com:2222?IdentityFile=/path/to/private/key&StrictRemoteKeyChecking=yes"
     host = Remote.from_ssh_uri(machine_name="foo", address=addr).override(
-        host_key_check="strict"
+        host_key_check=HostKeyCheck.STRICT
     )
     assert host.address == "example.com"
     assert host.port == 2222

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

@@ -33,6 +33,7 @@ from clan_lib.nix_models.clan import (
 )
 from clan_lib.nix_models.clan import InventoryMachineDeploy as MachineDeploy
 from clan_lib.persist.util import set_value_by_path
+from clan_lib.ssh.host_key import HostKeyCheck
 from clan_lib.ssh.remote import Remote, can_ssh_login
 
 log = logging.getLogger(__name__)
@@ -198,7 +199,7 @@ def test_clan_create_api(
     clan_dir_flake.invalidate_cache()
 
     target_host = machine.target_host().override(
-        private_key=private_key, host_key_check="none"
+        private_key=private_key, host_key_check=HostKeyCheck.NONE
     )
     result = can_ssh_login(target_host)
     assert result == "Online", f"Machine {machine.name} is not online"