feat: apt's proxy through AptProxyMixin (NetOrk/netork#1397)

get_package_proxy() is what apt-config dump says, not 00proxy alone: a
proxy in 90curtin-aptproxy or /etc/apt/apt.conf wins over it and was
missed. The driver now supplies only the transports: reads on the exec
channel, root commands through _root_outcome, the file through the staged
_install_file_as_root. New: get_package_proxy_report() and
check_package_proxy(). configure_package_proxy() also comments out other
proxy lines, reads the result back and fetches through the proxy.

Requires napalm-device-types 4.22.0; version 0.14.0.

napalm_linux/linux.py

@@ -46,7 +46,7 @@ from napalm_device_types import (
     ListeningSocketsMixin,
     OpenSshServerMixin,
     OSDriver,
-    PackageProxyMixin,
+    AptProxyMixin,
     ServiceClustersMixin,
     ServicePackagesMixin,
     SnmpAgentMixin,
@@ -261,8 +261,6 @@ _SNMP_INSTALL = {
     "apk": "apk add --no-cache net-snmp net-snmp-tools 2>&1",
     "pacman": "pacman -Sy --noconfirm net-snmp 2>&1",
 }
-_APT_PROXY_CONF = "/etc/apt/apt.conf.d/00proxy"
-_PROXY_URL = re.compile(r"^https?://[A-Za-z0-9.\-\[\]:@%_~/]+$")
 _USER_NAME = re.compile(r"^[a-z_][a-z0-9_.\-]{0,31}$")
 #: What may stand in an snmpd.conf value: no whitespace, no quote, no comment.
 _SNMP_WORD = re.compile(r"^[^\s\"#]+$")
@@ -294,7 +292,7 @@ def render_snmpd_conf(settings: SnmpAgentSettingsDict) -> str:
 class LinuxDriver(
     SnmpAgentMixin,
     EnsurePackageMixin,
-    PackageProxyMixin,
+    AptProxyMixin,
     KernelFactsMixin,
     ServicePackagesMixin,
     ListeningSocketsMixin,
@@ -1544,14 +1542,6 @@ class LinuxDriver(
             f"Package manager '{self._pkg_manager}' is not supported"
         )
 
-    def get_package_proxy(self) -> str | None:
-        """The proxy apt fetches through (``00proxy``); None for none or a non-apt host."""
-        if self._pkg_manager != "apt":
-            return None
-        conf = self._send(f"cat {_APT_PROXY_CONF} 2>/dev/null || true")
-        found = re.search(r'Acquire::http::Proxy\s+"([^"]+)"', conf)
-        return found.group(1) if found else None
-
     def _get_updates_apt(self) -> list[UpdateDict]:
         # apt list --upgradable does not need root; avoid sudo so it works even
         # without a configured sudo password.
@@ -2052,22 +2042,23 @@ class LinuxDriver(
             "snmpd enabled and running",
         )
 
-    def configure_package_proxy(self, url: str) -> FixResultDict:
-        """apt fetches through *url* (``/etc/apt/apt.conf.d/00proxy``); ``""`` removes it."""
+    # apt's proxy (napalm-device-types AptProxyMixin): the transports
 
-        def write() -> FixStepOutcomeDict:
-            if self._pkg_manager != "apt":
-                return {"ok": False, "output": f"package manager is {self._pkg_manager!r}, not apt"}
-            if not url:
-                return self._root_outcome(f"rm -f {_APT_PROXY_CONF}", 30, "proxy removed")
-            if not _PROXY_URL.match(url):
-                raise ValueError(f"not a proxy URL: {url!r}")
-            written = self._install_file_as_root(_APT_PROXY_CONF, f'Acquire::http::Proxy "{url}";\n')
-            if written.exit_code:
-                return {"ok": False, "output": (written.stdout or written.stderr).strip()[-300:]}
-            return {"ok": True, "output": f"apt fetches through {url}"}
+    def _is_apt_host(self) -> bool:
+        return self._pkg_manager == "apt"
 
-        return run_fix_steps([("configure", write)])
+    def _run_apt_command(self, command: str) -> str:
+        """On the exec channel: no prompt to mistake a line of apt's output for."""
+        return self.run_command(command, timeout=60).stdout
+
+    def _run_apt_root_command(self, command: str, done: str) -> FixStepOutcomeDict:
+        return self._root_outcome(command, 30, done)
+
+    def _write_apt_file(self, path: str, content: str) -> FixStepOutcomeDict:
+        written = self._install_file_as_root(path, content)
+        if written.exit_code:
+            return {"ok": False, "output": (written.stdout or written.stderr).strip()[-300:]}
+        return {"ok": True, "output": f"wrote {path}"}
 
     def grant_container_engine_access(self, user: str) -> FixResultDict:
         """Add *user* to the ``docker`` group, so the engine answers without sudo."""