feat!: declare the guest agent per guest OS, and share what provisioning needs

GUEST_AGENT_PACKAGES / GUEST_AGENT_RUNCMD described one agent per
hypervisor. A hypervisor that provisions FreeBSD and OpenBSD guests needs
a different agent per guest, and netOrk has to know which guests a driver
can provision at all (NetOrk/netork#794). Both now come from one
class-level mapping netOrk reads off the driver class:

    GUEST_AGENTS = {guest_os: (packages, runcmd)}

Its keys are the guests the driver provisions, and
create_vm_from_cloud_init(guest_os=...) refuses any other. The base keeps
Linux with qemu-guest-agent.

New module `provisioning`, generic for every hypervisor:
- QEMU_GUEST_AGENTS: the QEMU agent for Linux, FreeBSD and OpenBSD, with
  package names and service commands verified on FreeBSD 15.1 and
  OpenBSD 7.9 cloud images (NetOrk/netork#793).
- network_config(): cloud-init's network-config v2 with MAC matching,
  moved here from napalm-vmware. FreeBSD's nuageinit reads no other
  version.
- split_compression(): how a packed image (.xz, .gz, .bz2, .zst) is
  unpacked.

BREAKING CHANGE: GUEST_AGENT_PACKAGES and GUEST_AGENT_RUNCMD are gone;
drivers declare GUEST_AGENTS instead.

napalm_device_types/hypervisor.py

@@ -14,6 +14,7 @@ from typing import Any, Dict, List, TYPE_CHECKING
 from napalm_device_types.base import DeviceTypeDriver
 from napalm_device_types.packages import PackageManagementMixin
 from napalm_device_types.health_metrics import HealthMetricsMixin
+from napalm_device_types.provisioning import QEMU_GUEST_AGENTS, GuestAgents
 from napalm_device_types.models import (
     NICConfigDict,
     NetworkTargetDict,
@@ -44,11 +45,11 @@ class HypervisorDriver(PackageManagementMixin, HealthMetricsMixin, DeviceTypeDri
     ROLE: str = "hypervisor"
     TYPE_LABEL: str = "Hypervisor"
 
-    #: What cloud-init installs and starts on a VM provisioned through this
-    #: driver, so the hypervisor can read the guest's IP address back.
-    GUEST_AGENT_PACKAGES: tuple[str, ...] = ("qemu-guest-agent",)
-    GUEST_AGENT_RUNCMD: tuple[str, ...] = ("systemctl enable --now qemu-guest-agent",)
-
+    #: What cloud-init installs and runs on a VM provisioned through this
+    #: driver, per guest OS, so the hypervisor can read the guest's IP
+    #: address back. The guest operating systems listed here are the ones
+    #: the driver can provision; netOrk reads this off the class.
+    GUEST_AGENTS: GuestAgents = {"linux": QEMU_GUEST_AGENTS["linux"]}
 
 
     # ------------------------------------------------------------------
@@ -464,6 +465,7 @@ class HypervisorDriver(PackageManagementMixin, HealthMetricsMixin, DeviceTypeDri
             disk_resize_gb: int | None = None,
             storage: str | None = None,
             cpu_type: str | None = None,
+            guest_os: str = "linux",
             download_timeout: int = 300,
             timeout: int = 180,
         ) -> VMProvisionResultDict:
@@ -512,6 +514,13 @@ class HypervisorDriver(PackageManagementMixin, HealthMetricsMixin, DeviceTypeDri
                   value other than None with ValueError; one that has it raises
                   ValueError for a name it does not list or that is not
                   ``available`` on this node, before creating anything.
+                guest_os (string) - the operating system in the image, a key of
+                  ``GUEST_AGENTS`` (``"linux"``, ``"freebsd"``, ``"openbsd"``). The
+                  driver sets up the VM's hardware for it (OS type, how the guest
+                  agent is attached) and, where the guest needs it, writes the
+                  network-config itself (``provisioning.network_config``). A
+                  guest_os the driver does not list raises ValueError before
+                  anything is created. Default ``"linux"``.
                 download_timeout (int) - maximum seconds to wait for the image download
                   (skipped entirely if already cached on the hypervisor). Default 300.
                 timeout (int) - maximum seconds to wait for the remaining provisioning

napalm_device_types/provisioning.py

@@ -0,0 +1,64 @@
+"""
+What provisioning a VM from a cloud image needs to know about the guest.
+
+The same for every hypervisor: which agent a guest runs so a QEMU-based
+hypervisor can read its IP, the network-config cloud-init and FreeBSD's
+nuageinit both read, and how a packed cloud image is unpacked. How a
+hypervisor attaches, boots and talks to the VM stays in its driver.
+"""
+
+from __future__ import annotations
+
+from collections.abc import Mapping
+from typing import Any
+
+#: ``{guest_os: (packages, runcmd)}``: what cloud-init installs and runs so
+#: the hypervisor can read the guest's IP address back.
+GuestAgents = Mapping[str, tuple[tuple[str, ...], tuple[str, ...]]]
+
+#: The QEMU guest agent per guest OS, for hypervisors built on QEMU. Package
+#: names and service commands were verified on FreeBSD 15.1 and OpenBSD 7.9
+#: cloud images (NetOrk/netork#793).
+QEMU_GUEST_AGENTS: GuestAgents = {
+    "linux": (("qemu-guest-agent",), ("systemctl enable --now qemu-guest-agent",)),
+    "freebsd": (
+        ("qemu-guest-agent",),
+        ("sysrc qemu_guest_agent_enable=YES", "service qemu-guest-agent start"),
+    ),
+    "openbsd": (("qemu-ga",), ("rcctl enable qemu_ga", "rcctl start qemu_ga")),
+}
+
+#: Suffix of a packed image -> the command that writes it unpacked to stdout.
+_DECOMPRESSORS = {
+    "xz": "xz -dc",
+    "gz": "gzip -dc",
+    "bz2": "bzip2 -dc",
+    "zst": "zstd -dc",
+}
+
+
+def network_config(nics: list[tuple[str, bool]]) -> dict[str, Any] | None:
+    """Network-config v2: DHCP on every ``(mac, dhcp)`` NIC that asks for it.
+
+    Version 2 because FreeBSD's nuageinit reads no other: given the v1 that
+    Proxmox generates, it fails and skips the rest of its first stage,
+    runcmd included. ``None`` when no NIC wants DHCP, so the guest is left
+    alone rather than told to configure nothing.
+    """
+    ethernets = {
+        f"nic{i}": {"match": {"macaddress": mac.lower()}, "dhcp4": True}
+        for i, (mac, dhcp) in enumerate(nics)
+        if dhcp
+    }
+    return {"version": 2, "ethernets": ethernets} if ethernets else None
+
+
+def split_compression(filename: str) -> tuple[str, str | None]:
+    """``(unpacked filename, command that unpacks to stdout)`` for *filename*.
+
+    The command is None for an image that is not packed, which is then
+    imported as it is.
+    """
+    stem, dot, suffix = filename.rpartition(".")
+    command = _DECOMPRESSORS.get(suffix.lower()) if dot and stem else None
+    return (stem, command) if command else (filename, None)