fix: WireGuard peers keep their tunnel key when others come and go (#32)

get_vpn_tunnels() keyed WireGuard peers with a running counter over the
peer rows, so a peer added ahead of an existing one renumbered every peer
after it. Whatever a consumer stores per key moved with it: netOrk's site
link and tunnel check ended up on a new, offline peer and alarmed while the
real tunnel was up.

The key is now the interface and the start of the public key, as in
napalm-linux, made URL-safe because the key is a path segment. Two peers
sharing the prefix get the whole key; a row without a public key keeps its
position. IPsec and OpenVPN keys were already stable.

Every WireGuard key changes once; netOrk carries its
per-tunnel metadata across (netork#1654).

tests/unit/test_vpn_tunnels.py

@@ -0,0 +1,106 @@
+"""WireGuard peers in ``get_vpn_tunnels()`` keep their key when others come and go (#32).
+
+The key was a running counter over the peer rows, so a peer added ahead of an
+existing one renumbered every peer after it, and whatever a consumer stored per
+key (netOrk's site link, its tunnel check) silently moved to another peer. A
+peer is its interface and its public key, so that is what the key is made of.
+"""
+
+from __future__ import annotations
+
+from unittest.mock import MagicMock, patch
+
+from napalm_opnsense.opnsense import OPNsenseDriver
+
+OFFICE = {
+    "if": "wg0",
+    "type": "peer",
+    "name": "office",
+    "public-key": "aBcD1234efGH5678ijKL9012mnOP3456qrST7890uvw=",
+    "endpoint": "198.51.100.7:51820",
+    "peer-status": "online",
+    "transfer-rx": 10,
+    "transfer-tx": 20,
+    "latest-handshake-age": 45,
+}
+LAPTOP = {
+    "if": "wg0",
+    "type": "peer",
+    "name": "laptop",
+    "public-key": "Zz9/+yXw8765vuTS4321rqPO0987nmLK6543jiHG210=",
+    "endpoint": "(none)",
+    "peer-status": "offline",
+}
+SERVER = {
+    "if": "wg1",
+    "type": "peer",
+    "name": "server",
+    "public-key": "QqQqWwWwEeEeRrRrTtTtYyYyUuUuIiIiOoOoPpPp123=",
+    "endpoint": "203.0.113.9:51821",
+    "peer-status": "online",
+}
+
+
+def _driver(*rows: dict) -> OPNsenseDriver:
+    with patch("napalm_opnsense.opnsense.requests.Session"):
+        drv = OPNsenseDriver(hostname="fw", username="k", password="s")
+    drv.session = MagicMock()
+    show = {"rows": [{"if": "wg0", "type": "interface"}, *rows]}
+
+    def get(path: str) -> dict:
+        if path == "/api/wireguard/service/show":
+            return show
+        raise RuntimeError("not installed")  # IPsec and OpenVPN are not part of this
+
+    drv._get = get  # type: ignore[method-assign]
+    return drv
+
+
+def _by_name(tunnels: dict) -> dict[str, str]:
+    return {t["description"]: key for key, t in tunnels.items()}
+
+
+class TestTheKey:
+    def test_is_the_interface_and_the_start_of_the_public_key(self):
+        assert list(_driver(OFFICE).get_vpn_tunnels()) == ["wireguard-wg0-aBcD1234"]
+
+    def test_survives_a_peer_added_ahead_of_it(self):
+        before = _by_name(_driver(OFFICE, SERVER).get_vpn_tunnels())
+        after = _by_name(_driver(OFFICE, LAPTOP, SERVER).get_vpn_tunnels())
+        assert after["server"] == before["server"]
+        assert after["office"] == before["office"]
+
+    def test_is_safe_in_a_url_path(self):
+        # The key is a path segment (PATCH /devices/{id}/vpn-tunnels/{key}), and
+        # a "/" from base64 would split it even when encoded.
+        key = _by_name(_driver(LAPTOP).get_vpn_tunnels())["laptop"]
+        assert key == "wireguard-wg0-Zz9_-yXw"
+
+    def test_two_peers_with_the_same_key_start_both_stay(self):
+        twin = {
+            **SERVER,
+            "if": "wg0",
+            "name": "twin",
+            "public-key": OFFICE["public-key"][:8] + "x=",
+        }
+        tunnels = _driver(OFFICE, twin).get_vpn_tunnels()
+        assert len(tunnels) == 2
+
+    def test_without_a_public_key_falls_back_to_the_position(self):
+        keyless = {k: v for k, v in OFFICE.items() if k != "public-key"}
+        assert list(_driver(keyless).get_vpn_tunnels()) == ["wireguard-1"]
+
+
+class TestTheEntry:
+    def test_carries_the_peer_s_reading(self):
+        tunnel = _driver(OFFICE).get_vpn_tunnels()["wireguard-wg0-aBcD1234"]
+        assert tunnel == {
+            "type": "WireGuard",
+            "local_endpoint": "",
+            "remote_endpoint": "198.51.100.7",
+            "is_up": True,
+            "uptime": 45,
+            "bytes_in": 10,
+            "bytes_out": 20,
+            "description": "office",
+        }