napalm-device-types/README.md

# napalm-device-types

Abstract intermediate device-type base classes for [NAPALM](https://napalm.readthedocs.io/) drivers.

Instead of inheriting directly from `napalm.base.NetworkDriver`, a driver can inherit from one of the device-type classes here to gain a richer, type-specific contract:

```python
# without napalm-device-types
class OpenWrtDriver(NetworkDriver):
    ...

# with napalm-device-types
from napalm_device_types import AccessPointDriver

class OpenWrtDriver(AccessPointDriver):
    ...
```

## Why?

NAPALM's `NetworkDriver` defines a common interface for all network devices. In practice, devices fall into distinct categories with very different capabilities. A switch exposes spanning-tree and PoE data; a firewall exposes NAT tables and VPN tunnels; a NAS exposes disk pools and shares. Writing these methods directly in a concrete driver mixes concerns and makes drivers harder to discover and compare.

`napalm-device-types` sits in between: it adds one well-typed layer of abstract methods per device category, so every driver for the same category exposes the same interface.

## Roles: what a device *is*

A device is often several things at once. A QNAP NAS runs VMs on a Linux userland; an
OpenMediaVault box is a NAS built on Debian. So a driver inherits **one role base per
role its device fills**, and **the order it lists them in is the ranking**:

```python
class QnapQtsDriver(StorageDriver, HypervisorDriver, LinuxDriver):
    ...   # primary_role_of(...) == "storage"
```

`roles_of(cls)`, `role_keys_of(cls)` and `primary_role_of(cls)` read that back. Nothing
restates the ranking: there is no precedence table and no attribute to override.

### Role bases declare; they never implement

**A role base must not contain a single runtime method — not even a
`NotImplementedError` placeholder.** Its methods are declared under `if TYPE_CHECKING`:

```python
class StorageDriver(DeviceTypeDriver):
    """Contract, not code."""
    ROLE: str = "storage"
    TYPE_LABEL: str = "Storage"

    if TYPE_CHECKING:                      # nothing exists at runtime
        def get_disks(self) -> List[PhysicalDiskDict]: ...
```

This is not a style preference. A placeholder on a base class is not neutral under
multiple inheritance: it wins the MRO against a sibling base's *working* implementation
and silently replaces it. Adding one stub to a base is therefore a breaking change for
every driver that mixes that base with another. It happened three times here before the
rule existed, and each time the fix was hand-written forwarding methods in the driver.

Two things follow, and both are improvements:

- **`hasattr` is truthful again.** A method exists on a driver class exactly when that
  driver implemented it, which is how netOrk asks "can this driver list disks".
- **A method that was never implemented raises `AttributeError`, not
  `NotImplementedError`.** Ask before calling.

## Function classes: what a device *can do*

Behaviour shared across roles lives in a function class, exactly once, and a role base
is a thin bundle over them — `PackageManagementMixin`, `HealthMetricsMixin`,
`ServiceControlMixin`, `UpdateMixin`, `NatVpnMixin`, `MacAclMixin`, `FirewallRuleMixin`,
`DhcpServerMixin`, `PingSweepMixin`, `ConfigLifecycleMixin`, `InterfaceFilterMixin`.
`HostRebootMixin` (`reboot_host`) is mixed into `DeviceTypeDriver` itself, since any
device may be restartable; like the others it only declares.

`KernelFactsMixin` (`get_kernel_facts`) is the exception that is mixed in by a driver
rather than by a role base: what a Linux kernel has built and loaded is read the same way
everywhere, so the command and its parse are concrete here and a driver supplies only
`_run_kernel_facts_command`. `OSDriver` does not carry it — a Windows host is an OS driver
too, and `hasattr(driver, "get_kernel_facts")` has to stay truthful.

`HostStatusMixin` (`get_host_status`) is mixed in the same way: whether a Linux host needs
a reboot to finish an update (`/var/run/reboot-required`, `needs-restarting -r`, or a newer
kernel of the running flavour installed) and whether it patches itself (unattended-upgrades,
dnf-automatic). `package_updates` holds the shared apt and dnf parsers: apt's suites become
an update's `origin`, a `-security` suite makes it a security update, and dnf's security
advisories do the same.

`ListeningSocketsMixin` (`get_listening_sockets`) is mixed in the same way: every listening
TCP and bound UDP socket from `ss -lntup`, with the systemd service or container behind it
from `/proc/<pid>/cgroup`, in one round trip. A driver supplies
`_run_listening_sockets_command(command, privileged=)`; the command arrives as one `sh -c`
argument, so a `sudo -n` prefix covers all of it. Without root `ss` names only the login
user's processes, and the reading says so (`attributed: false`) instead of failing. A host
without `ss` is read with `netstat -lntup` (OpenWrt's busybox, old net-tools); on OpenWrt the
cgroup names the procd service (`/services/<name>/<instance>`). A host with neither raises
`ListeningSocketsUnavailable`.

**Update readers raise when they cannot read.** `get_available_updates` returns an empty
list only when nothing is pending; netOrk keeps "pending since" per package, and an empty
list for "don't know" would reset it.

`SystemdServicesMixin` (`get_services`, `manage_service`) is mixed in the same way, by
the drivers whose host runs systemd. Listing the services, checking a unit name and
reading an action's exit status are the same on every such host, so they are concrete
here, and a driver supplies only `_run_service_command(command, *, privileged, timeout)`
— how a command reaches its host and how it gains root there. The listing is one round
trip (`list-unit-files` plus one `systemctl show` over every loaded unit) instead of an
`is-enabled` and a `show` per unit. A host without systemd raises `SystemdUnavailable`,
a `NotImplementedError`, so a driver can fall back to another init system.

### Access channels: why there is no container model here

`CommandChannelMixin` declares a driver's public channel to its host:
- `run_command(command, *, privileged=False, timeout=60, stdin=None)` returns a `CommandResult(stdout, stderr, exit_code)`;
- `open_stream(command, *, privileged=False)` returns a `ByteStream` to the command's stdin and stdout.

The mixin sits in `DeviceTypeDriver` and only declares, so `hasattr(driver, "run_command")` is true exactly where a driver implements it. For SSH drivers, `channel.run_on_transport` and `channel.open_stream_on_transport` are the implementation over a paramiko exec channel: no PTY, stderr kept apart, a real exit code. How a command gains root stays with the driver.

**`ContainerEngineMixin` is deliberately different from `SystemdServicesMixin`.** The systemd mixin owns its command and its parse; this one owns neither.
- `container_engines()` says which engines the host offers (`[{"engine": "docker", "api": "docker-engine"}]`).
- `open_container_engine(engine)` returns a `ContainerEngineConnection`:
  - `open_api()` is a stream to the engine's API (`docker system dial-stdio`);
  - `run_cli(args)` and `stream_cli(args)` run the engine's CLI with arguments the caller chooses.
- The driver decides only *how* the engine is reached. Its hook `_container_engine_binary(engine)` returns, for QNAP, the Container Station path, and the caller never sees it.

**What runs on the engine, and what to do with it, is netOrk's** (NetOrk/netork#765): the container model, the Engine API requests, compose, updates. Above the connection everything is specific to the service, so this package abstracts the connection and nothing more.

A driver mixes `ContainerEngineMixin` in itself; `OSDriver` does not carry it. A Windows host is an OS driver too, and has no `dial-stdio` to offer over WinRM.

**Never half-close early.** `ByteStream.write` does not close anything; only `close_write` does. `dial-stdio` hands the daemon a half-close as "client gone", and the daemon then answers an unfinished request with HTTP 499.

A function class may use the **template form** — public method concrete, the
device-specific part a `_hook` declared under `if TYPE_CHECKING` — *when the base
genuinely does work* on the result: normalising, sorting, validating, or orchestrating
several hooks. `ConfigLifecycleMixin.compare_config` over `_get_running_config` is the
model. Where the base would only pass the call through, declare the method directly;
two names for one pass-through is ceremony, not design.

NAPALM's own getters (`get_facts`, `get_interfaces`, `ping`, `get_config`) are never
wrapped in a template — they belong to NAPALM, and code outside this repo relies on
their contract.

## Design principle: generic vs. device-specific logic

When adding behavior to a device-type base class, split it along one line: **would
this exact logic work unchanged for a different vendor's driver of the same
device-type, if that driver only implemented the same abstract methods?**

- If yes, it's generic — implement it once as a **concrete** method on the
  device-type base class (here, in this repo).
- If no — it talks to the device itself (a specific REST endpoint, a CLI command,
  a vendor-specific payload format) — it belongs in the concrete driver as the
  implementation of an **abstract** method the base class declares.

Concretely: matching/comparison/reconciliation algorithms, orchestration flows, and
generic data shapes belong here. Only the actual device communication belongs in
`vendor/napalm-<name>`.

**Worked example — firewall rule diff/apply** (`FirewallDriver`):

```python
class FirewallDriver(DeviceTypeDriver):
    # Abstract — every driver implements its own device communication.
    def get_firewall_rules(self) -> List[FirewallRuleDict]: raise NotImplementedError
    def apply_firewall_rule(self, rule: FirewallRuleDict, *, uuid: Optional[str] = None) -> Dict[str, Any]: raise NotImplementedError
    def commit_firewall_rules(self) -> Dict[str, Any]: raise NotImplementedError

    # Concrete — the matching/comparison/orchestration algorithm is identical
    # for every firewall vendor, so it lives here once.
    def diff_firewall_rules(self, desired: List[FirewallRuleDict]) -> FirewallRuleDiffDict:
        ...  # matches self.get_firewall_rules() against `desired` by description

    def apply_firewall_ruleset(self, desired: List[FirewallRuleDict]):
        ...  # computes the diff, calls apply_firewall_rule() per change, commits
```

The same split applies to `DhcpServerMixin`: `get_dhcp_reservations`/
`apply_dhcp_reservation`/`commit_dhcp_reservations` are abstract (Kea REST on
OPNsense, dnsmasq/odhcpd UCI on OpenWrt), while `diff_dhcp_reservations` and
`apply_dhcp_reservationset` are concrete — matching by normalised MAC and the
apply-then-commit orchestration are identical for every DHCP server.

A new driver (FortiGate, pfSense, …) gets `diff_firewall_rules`/
`apply_firewall_ruleset` for free the moment it implements the three abstract
methods — it never needs to reimplement the reconciliation logic itself.

**Second worked example — ping sweeps** (`PingSweepMixin`, mixed into
`DeviceTypeDriver`, so *every* device-type driver has it):

```python
class PingSweepMixin:
    # Concrete — the loop, the reply parsing, the target cap and the progress
    # reporting are the same for every device that can ping at all.
    def ping_sweep(self, destinations, *, count=1, timeout=1, …) -> PingSweepResultDict:
        ...  # calls NAPALM's standard ping() once per destination
```

A driver becomes a usable sweep source the moment it implements NAPALM's
`ping()` — nothing else is required, and `driver_supports_ping(cls)` reports
whether it did (introspection, not a hand-maintained list). A driver whose
device offers something genuinely faster overrides `ping_sweep` and keeps the
return shape: `napalm-opnsense` starts a batch of ping jobs over the
diagnostics API, waits once for all of them, and reads every result with a
single request — a per-host loop would be unusable there.

This mirrors a similar split already documented on the consumer side, in NetOrk's
`docs/ARCHITECTURE.md` ("Device Warnings — Trennung von Erkennung und
Präsentation"): drivers return raw signals, the higher layer gives them meaning.
Same shape of separation, different axis — device-specific vs. generic here,
detection vs. presentation there.

## Installation

```bash
pip install napalm-device-types
```

Requires Python ≥ 3.9 and NAPALM ≥ 4.0.

## Available base classes

| Class | Target devices | Example implementations |
|---|---|---|
| `AccessPointDriver` | Wireless access points | OpenWrt, Ubiquiti UniFi, Cisco Meraki AP |
| `SwitchDriver` | Ethernet switches | Cisco IOS, Arista EOS, Juniper EX |
| `FirewallDriver` | Firewalls & UTM appliances | pfSense, Fortinet FortiOS, Cisco ASA |
| `HypervisorDriver` | Hypervisors & virtualisation platforms | Proxmox VE, VMware ESXi, KVM/libvirt |
| `OSDriver` | General-purpose operating systems | Linux, BSD, macOS |
| `StorageDriver` | Storage appliances & NAS/SAN | TrueNAS, Synology DSM, QNAP QTS |
| `ResidentialGatewayDriver` | Router + firewall + AP in one box | OpenWrt, FritzBox |

Mixins mixed into the classes above rather than used on their own:
`ConfigLifecycleMixin` (config load/compare/commit/rollback), `PingSweepMixin`
(subnet sweeps), and `DhcpServerMixin` (static DHCP reservations — mixed into
`FirewallDriver` and `ResidentialGatewayDriver`, since both commonly run the
DHCP server for their networks).

## Usage

### Access Point

```python
from napalm_device_types import AccessPointDriver

class OpenWrtDriver(AccessPointDriver):

    def get_wireless_clients(self):
        # return List[WirelessClientDict]
        ...

    def get_ssids(self):
        # return Dict[str, SSIDDict]
        ...
```

### Switch

```python
from napalm_device_types import SwitchDriver

class CiscoIOSDriver(SwitchDriver):

    def get_spanning_tree(self):
        # return Dict[str, SpanningTreeDict]
        ...

    def get_poe_status(self):
        # return PoESummaryDict
        ...
```

### Firewall

```python
from napalm_device_types import FirewallDriver

class PfSenseDriver(FirewallDriver):

    def get_nat_translations(self):
        # return List[NATTranslationDict]
        ...

    def get_vpn_tunnels(self):
        # return Dict[str, VPNTunnelDict]
        ...

    def get_port_forwards(self):
        # return List[PortForwardDict] — forwards from the WAN only, never a
        # redirect between internal networks (shared with home gateways)
        ...
```

### Hypervisor

```python
from napalm_device_types import HypervisorDriver

class ProxmoxDriver(HypervisorDriver):

    def get_vms(self):
        # return List[VMDict]
        ...

    def create_vm_snapshot(self, name, snapshot, description="", include_memory=False):
        ...

    def get_vm_cpu_types(self):
        # optional — return List[VMCpuTypeDict]: the CPU models a new VM may get
        # on this node, each with its cpuinfo flags and whether the node can run
        # it; the name goes to create_vm_from_cloud_init(cpu_type=...)
        ...
```

### OS / Linux

```python
from napalm_device_types import OSDriver

class LinuxDriver(OSDriver):

    def get_packages(self):
        # return List[PackageDict]
        ...

    def get_services(self):
        # return List[ServiceDict]
        ...

    def get_users(self):
        # return List[UserDict]
        ...

    def get_processes(self):
        # return List[ProcessDict]
        ...

    def get_cron_jobs(self):
        # return List[CronJobDict]
        ...
```

### Storage / NAS

```python
from napalm_device_types import StorageDriver

class TrueNASDriver(StorageDriver):

    def get_disks(self):
        # return List[PhysicalDiskDict]
        ...

    def get_shares(self):
        # return Dict[str, NASShareDict]
        ...
```

## Return types

All return types are `TypedDict` classes defined in `napalm_device_types.models`. Import them directly for type annotations in your driver:

```python
from napalm_device_types.models import (
    PhysicalDiskDict,
    DiskPoolDict,
    NASShareDict,
    VolumeSnapshotDict,
)
```

## Development

```bash
git clone https://github.com/chrismanivong/napalm-device-types.git
cd napalm-device-types
pip install -e ".[dev]"
```

Run type-checking:

```bash
mypy napalm_device_types
```

## Contributing

1. Fork the repository
2. Create a feature branch (`git checkout -b feature/router-driver`)
3. Implement your changes
4. Open a Pull Request

## License

Apache-2.0 – see [LICENSE](LICENSE) for details.