feat: set_hostname — update /etc/hostname, /etc/hosts, cert, Postfix

Implements set_hostname on ProxmoxSystemMixin:
1. Writes /etc/hostname (short name, base64-safe transfer)
2. Replaces old hostname in /etc/hosts via Python regex + base64
3. Updates /etc/mailname if present
4. Updates Postfix myhostname via postconf -e if installed
5. Applies hostname immediately at runtime via hostname(1)
6. Regenerates Proxmox node TLS certificate via pvecm updatecerts -f
   (falls back to pvenode cert create → pveproxy restart)

Accepts bare hostname or FQDN. A reboot is required for the Proxmox
node name to update in the web UI / cluster — the driver logs this.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

napalm_proxmox/config_mixin.py

@@ -0,0 +1,145 @@
+# Copyright 2025 The NetOrk Project Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Configuration management NAPALM methods for Proxmox VE nodes."""
+
+from __future__ import annotations
+
+import re
+from typing import Any
+
+
+_JsonDict = dict[str, Any]
+
+
+class ProxmoxConfigMixin:
+    """Mixin providing configuration-management NAPALM methods."""
+
+    def get_config(
+        self,
+        retrieve: str = "all",
+        full: bool = False,
+        sanitized: bool = False,
+        format: str = "text",
+    ) -> _JsonDict:
+        """Return the node network configuration.
+
+        ``running`` config is the contents of ``/etc/network/interfaces``
+        (and the SDN config directory).  ``startup`` is identical (PVE
+        applies on boot).  ``candidate`` is what was loaded via
+        ``load_merge_candidate`` / ``load_replace_candidate`` but not yet
+        committed.
+        """
+        configs: _JsonDict = {"running": "", "candidate": "", "startup": ""}
+
+        if retrieve in ("running", "all", "startup"):
+            raw = self._exec_ssh_command(
+                "cat /etc/network/interfaces 2>/dev/null || true"
+            )
+            # Append SDN config if available
+            sdn_raw = self._exec_ssh_command(
+                "cat /etc/pve/sdn/vnets.cfg 2>/dev/null || true"
+            )
+            running = raw
+            if sdn_raw:
+                running += "\n# === SDN VNets ===\n" + sdn_raw
+            if sanitized:
+                running = re.sub(r"password\s+\S+", "password ****", running)
+            configs["running"] = running
+            self._running_config = running
+            if retrieve == "startup":
+                configs["startup"] = running
+            elif retrieve == "all":
+                configs["startup"] = running
+
+        if retrieve in ("candidate", "all"):
+            configs["candidate"] = self._candidate_config
+
+        return configs
+
+    def load_merge_candidate(
+        self,
+        filename: str | None = None,
+        config: str | None = None,
+    ) -> None:
+        """Load a candidate configuration (merge mode)."""
+        if filename:
+            with open(filename) as fh:
+                config = fh.read()
+        if config is None:
+            raise ValueError("Either filename or config must be provided")
+        # In merge mode we append / overlay
+        self._candidate_config = config
+
+    def load_replace_candidate(
+        self,
+        filename: str | None = None,
+        config: str | None = None,
+    ) -> None:
+        """Load a candidate configuration (replace mode)."""
+        if filename:
+            with open(filename) as fh:
+                config = fh.read()
+        if config is None:
+            raise ValueError("Either filename or config must be provided")
+        self._candidate_config = config
+
+    def compare_config(self) -> str:
+        """Return a unified diff between running and candidate config."""
+        import difflib
+
+        if not self._running_config:
+            self.get_config(retrieve="running")
+        running_lines = self._running_config.splitlines(keepends=True)
+        candidate_lines = self._candidate_config.splitlines(keepends=True)
+        diff = difflib.unified_diff(
+            running_lines,
+            candidate_lines,
+            fromfile="running",
+            tofile="candidate",
+        )
+        return "".join(diff)
+
+    def commit_config(self, message: str = "", revert_in: int | None = None) -> None:
+        """Commit the candidate configuration to the Proxmox node.
+
+        This writes the candidate config to ``/etc/network/interfaces``
+        via the Proxmox node/network PUT API (which applies it live).
+
+        .. note::
+            Full programmatic apply requires the Proxmox API to accept raw
+            interface configs.  This implementation uses ``pvesh`` via exec
+            which requires the node exec endpoint to be available.
+        """
+        if not self._candidate_config:
+            return
+        # Write via exec endpoint
+        escaped = self._candidate_config.replace("'", "'\\''")
+        self._exec_ssh_command(
+            f"printf '%s' '{escaped}' > /etc/network/interfaces && "
+            "ifreload -a 2>&1 || ifup -a 2>&1 || true"
+        )
+        self._running_config = self._candidate_config
+        self._candidate_config = ""
+
+    def discard_config(self) -> None:
+        """Discard the candidate configuration."""
+        self._candidate_config = ""
+
+    def rollback(self) -> None:
+        """Revert to the stored running configuration."""
+        if self._running_config:
+            self._candidate_config = self._running_config
+            self.commit_config()
+        self._candidate_config = ""