Support SNMPv3 and asyncio in snmp sensor (#14753)

* snmp sensor: Add asyncio support and reuse SnmpEngine object

* snmp sensor: Support protocol v3

* Fix lint issue

homeassistant/components/sensor/snmp.py

@@ -14,7 +14,7 @@ from homeassistant.components.sensor import PLATFORM_SCHEMA
 from homeassistant.helpers.entity import Entity
 from homeassistant.const import (
     CONF_HOST, CONF_NAME, CONF_PORT, CONF_UNIT_OF_MEASUREMENT, STATE_UNKNOWN,
-    CONF_VALUE_TEMPLATE)
+    CONF_USERNAME, CONF_VALUE_TEMPLATE)
 
 REQUIREMENTS = ['pysnmp==4.4.5']
 
@@ -23,6 +23,10 @@ _LOGGER = logging.getLogger(__name__)
 CONF_BASEOID = 'baseoid'
 CONF_COMMUNITY = 'community'
 CONF_VERSION = 'version'
+CONF_AUTH_KEY = 'auth_key'
+CONF_AUTH_PROTOCOL = 'auth_protocol'
+CONF_PRIV_KEY = 'priv_key'
+CONF_PRIV_PROTOCOL = 'priv_protocol'
 CONF_ACCEPT_ERRORS = 'accept_errors'
 CONF_DEFAULT_VALUE = 'default_value'
 
@@ -31,10 +35,32 @@ DEFAULT_HOST = 'localhost'
 DEFAULT_NAME = 'SNMP'
 DEFAULT_PORT = '161'
 DEFAULT_VERSION = '1'
+DEFAULT_AUTH_PROTOCOL = 'none'
+DEFAULT_PRIV_PROTOCOL = 'none'
 
 SNMP_VERSIONS = {
     '1': 0,
-    '2c': 1
+    '2c': 1,
+    '3': None
+}
+
+MAP_AUTH_PROTOCOLS = {
+    'none': 'usmNoAuthProtocol',
+    'hmac-md5': 'usmHMACMD5AuthProtocol',
+    'hmac-sha': 'usmHMACSHAAuthProtocol',
+    'hmac128-sha224': 'usmHMAC128SHA224AuthProtocol',
+    'hmac192-sha256': 'usmHMAC192SHA256AuthProtocol',
+    'hmac256-sha384': 'usmHMAC256SHA384AuthProtocol',
+    'hmac384-sha512': 'usmHMAC384SHA512AuthProtocol',
+}
+
+MAP_PRIV_PROTOCOLS = {
+    'none': 'usmNoPrivProtocol',
+    'des': 'usmDESPrivProtocol',
+    '3des-ede': 'usm3DESEDEPrivProtocol',
+    'aes-cfb-128': 'usmAesCfb128Protocol',
+    'aes-cfb-192': 'usmAesCfb192Protocol',
+    'aes-cfb-256': 'usmAesCfb256Protocol',
 }
 
 SCAN_INTERVAL = timedelta(seconds=10)
@@ -50,14 +76,22 @@ PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
     vol.Optional(CONF_UNIT_OF_MEASUREMENT): cv.string,
     vol.Optional(CONF_VALUE_TEMPLATE): cv.template,
     vol.Optional(CONF_VERSION, default=DEFAULT_VERSION): vol.In(SNMP_VERSIONS),
+    vol.Optional(CONF_USERNAME): cv.string,
+    vol.Optional(CONF_AUTH_KEY): cv.string,
+    vol.Optional(CONF_AUTH_PROTOCOL, default=DEFAULT_AUTH_PROTOCOL):
+        vol.In(MAP_AUTH_PROTOCOLS),
+    vol.Optional(CONF_PRIV_KEY): cv.string,
+    vol.Optional(CONF_PRIV_PROTOCOL, default=DEFAULT_PRIV_PROTOCOL):
+        vol.In(MAP_PRIV_PROTOCOLS),
 })
 
 
-def setup_platform(hass, config, add_entities, discovery_info=None):
+async def async_setup_platform(
+        hass, config, async_add_entities, discovery_info=None):
     """Set up the SNMP sensor."""
-    from pysnmp.hlapi import (
+    from pysnmp.hlapi.asyncio import (
         getCmd, CommunityData, SnmpEngine, UdpTransportTarget, ContextData,
-        ObjectType, ObjectIdentity)
+        ObjectType, ObjectIdentity, UsmUserData)
 
     name = config.get(CONF_NAME)
     host = config.get(CONF_HOST)
@@ -66,6 +100,11 @@ def setup_platform(hass, config, add_entities, discovery_info=None):
     baseoid = config.get(CONF_BASEOID)
     unit = config.get(CONF_UNIT_OF_MEASUREMENT)
     version = config.get(CONF_VERSION)
+    username = config.get(CONF_USERNAME)
+    authkey = config.get(CONF_AUTH_KEY)
+    authproto = config.get(CONF_AUTH_PROTOCOL)
+    privkey = config.get(CONF_PRIV_KEY)
+    privproto = config.get(CONF_PRIV_PROTOCOL)
     accept_errors = config.get(CONF_ACCEPT_ERRORS)
     default_value = config.get(CONF_DEFAULT_VALUE)
     value_template = config.get(CONF_VALUE_TEMPLATE)
@@ -73,27 +112,46 @@ def setup_platform(hass, config, add_entities, discovery_info=None):
     if value_template is not None:
         value_template.hass = hass
 
-    errindication, _, _, _ = next(
+    if version == '3':
-        getCmd(SnmpEngine(),
+        import pysnmp.hlapi.asyncio as hlapi
-               CommunityData(community, mpModel=SNMP_VERSIONS[version]),
+
-               UdpTransportTarget((host, port)),
+        if not authkey:
-               ContextData(),
+            authproto = 'none'
-               ObjectType(ObjectIdentity(baseoid))))
+        if not privkey:
+            privproto = 'none'
+
+        request_args = [
+            SnmpEngine(),
+            UsmUserData(
+                username, authKey=authkey or None, privKey=privkey or None,
+                authProtocol=getattr(hlapi, MAP_AUTH_PROTOCOLS[authproto]),
+                privProtocol=getattr(hlapi, MAP_PRIV_PROTOCOLS[privproto]),),
+            UdpTransportTarget((host, port)),
+            ContextData(),
+        ]
+    else:
+        request_args = [
+            SnmpEngine(),
+            CommunityData(community, mpModel=SNMP_VERSIONS[version]),
+            UdpTransportTarget((host, port)),
+            ContextData(),
+        ]
+
+    errindication, _, _, _ = await getCmd(
+        *request_args, ObjectType(ObjectIdentity(baseoid)))
 
     if errindication and not accept_errors:
         _LOGGER.error("Please check the details in the configuration file")
-        return False
+        return
-    data = SnmpData(
+
-        host, port, community, baseoid, version, accept_errors,
+    data = SnmpData(request_args, baseoid, accept_errors, default_value)
-        default_value)
+    async_add_entities([SnmpSensor(data, name, unit, value_template)], True)
-    add_entities([SnmpSensor(data, name, unit, value_template)], True)
 
 
 class SnmpSensor(Entity):
     """Representation of a SNMP sensor."""
 
-    def __init__(self, data, name, unit_of_measurement,
+    def __init__(self, data, name, unit_of_measurement, value_template):
-                 value_template):
         """Initialize the sensor."""
         self.data = data
         self._name = name
@@ -116,9 +174,9 @@ class SnmpSensor(Entity):
         """Return the unit the value is expressed in."""
         return self._unit_of_measurement
 
-    def update(self):
+    async def async_update(self):
         """Get the latest data and updates the states."""
-        self.data.update()
+        await self.data.async_update()
         value = self.data.value
 
         if value is None:
@@ -133,30 +191,20 @@ class SnmpSensor(Entity):
 class SnmpData:
     """Get the latest data and update the states."""
 
-    def __init__(self, host, port, community, baseoid, version, accept_errors,
+    def __init__(self, request_args, baseoid, accept_errors, default_value):
-                 default_value):
         """Initialize the data object."""
-        self._host = host
+        self._request_args = request_args
-        self._port = port
-        self._community = community
         self._baseoid = baseoid
-        self._version = SNMP_VERSIONS[version]
         self._accept_errors = accept_errors
         self._default_value = default_value
         self.value = None
 
-    def update(self):
+    async def async_update(self):
         """Get the latest data from the remote SNMP capable host."""
-        from pysnmp.hlapi import (
+        from pysnmp.hlapi.asyncio import (getCmd, ObjectType, ObjectIdentity)
-            getCmd, CommunityData, SnmpEngine, UdpTransportTarget, ContextData,
+
-            ObjectType, ObjectIdentity)
+        errindication, errstatus, errindex, restable = await getCmd(
-        errindication, errstatus, errindex, restable = next(
+            *self._request_args, ObjectType(ObjectIdentity(self._baseoid)))
-            getCmd(SnmpEngine(),
-                   CommunityData(self._community, mpModel=self._version),
-                   UdpTransportTarget((self._host, self._port)),
-                   ContextData(),
-                   ObjectType(ObjectIdentity(self._baseoid)))
-            )
 
         if errindication and not self._accept_errors:
             _LOGGER.error("SNMP error: %s", errindication)