driver/power: add power backend for Shelly Gen2+

The API changed and no longer accepts POST for the legacy API. This
commit adds support for the "new" RPC API.

Ref: https://shelly-api-docs.shelly.cloud/gen2/General/RPCProtocol

Signed-off-by: Paul Spooren <[email protected]>
[bst: adjusted commit message to fit common style, fix typo. add doc
entry]
Signed-off-by: Bastian Krause <[email protected]>

Author: aparcar

doc/configuration.rst

@@ -228,6 +228,13 @@ Currently available are:
   <https://github.com/labgrid-project/labgrid/blob/master/labgrid/driver/power/shelly_gen1.py>`__
   for details.
 
+  ``shelly_gen2``
+  Controls relays of *Shelly* devices using the
+  `Gen2+ API <https://shelly-api-docs.shelly.cloud/gen2/General/RPCProtocol/>`__.
+  See the `docstring in the module
+  <https://github.com/labgrid-project/labgrid/blob/master/labgrid/driver/power/shelly_gen2.py>`__
+  for details.
+
 ``siglent``
   Controls *Siglent SPD3000X* series modules via the `vxi11 Python module
   <https://pypi.org/project/python-vxi11/>`_.

labgrid/driver/power/shelly_gen2.py

@@ -0,0 +1,30 @@
+"""Interface for controlling relays of Shelly devices using the Gen 2+ API
+
+  NetworkPowerPort:
+      model: shelly_gen2
+      host: 'http://192.168.0.42'
+      index: 0
+
+Will do a POST request to http://192.168.0.42/rpc to get the current
+relay state or change the state.
+
+Also, see the official Gen 2+ Device API documentation:
+https://shelly-api-docs.shelly.cloud/gen2/General/RPCProtocol
+"""
+
+import requests
+
+
+def power_set(host: str, port: int, index: int = 0, value: bool = True):
+    assert not port
+    payload = {"id": 1, "method": "Switch.Set", "params": {"id": index, "on": value}}
+    r = requests.post(f"{host}/rpc", json=payload)
+    r.raise_for_status()
+
+
+def power_get(host: str, port: int, index: int = 0):
+    assert not port
+    payload = {"id": 1, "method": "Switch.GetStatus", "params": {"id": index}}
+    r = requests.post(f"{host}/rpc", json=payload)
+    r.raise_for_status()
+    return r.json()["output"]