Add support for recording history to Apache Kafka

.coveragerc

@@ -34,6 +34,7 @@ omit =
     homeassistant/components/androidtv/*
     homeassistant/components/anel_pwrctrl/switch.py
     homeassistant/components/anthemav/media_player.py
+    homeassistant/components/apache_kafka/*
     homeassistant/components/apcupsd/*
     homeassistant/components/apple_tv/*
     homeassistant/components/aqualogic/*

homeassistant/components/apache_kafka/__init__.py

@@ -0,0 +1,111 @@
+"""Support for Apache Kafka."""
+from datetime import datetime
+import json
+import logging
+
+from aiokafka import AIOKafkaProducer
+import voluptuous as vol
+
+from homeassistant.const import (
+    CONF_IP_ADDRESS, CONF_PORT, EVENT_HOMEASSISTANT_STOP, EVENT_STATE_CHANGED,
+    STATE_UNAVAILABLE, STATE_UNKNOWN)
+import homeassistant.helpers.config_validation as cv
+from homeassistant.helpers.entityfilter import FILTER_SCHEMA
+
+_LOGGER = logging.getLogger(__name__)
+
+DOMAIN = 'apache_kafka'
+
+CONF_FILTER = 'filter'
+CONF_TOPIC = 'topic'
+
+CONFIG_SCHEMA = vol.Schema({
+    DOMAIN: vol.Schema({
+        vol.Required(CONF_IP_ADDRESS): cv.string,
+        vol.Required(CONF_PORT): cv.port,
+        vol.Required(CONF_TOPIC): cv.string,
+        vol.Optional(CONF_FILTER, default={}): FILTER_SCHEMA,
+    }),
+}, extra=vol.ALLOW_EXTRA)
+
+
+async def async_setup(hass, config):
+    """Activate the Apache Kafka integration."""
+    conf = config[DOMAIN]
+
+    kafka = hass.data[DOMAIN] = KafkaManager(
+        hass,
+        conf[CONF_IP_ADDRESS],
+        conf[CONF_PORT],
+        conf[CONF_TOPIC],
+        conf[CONF_FILTER])
+
+    hass.bus.async_listen(EVENT_HOMEASSISTANT_STOP, kafka.shutdown())
+
+    await kafka.start()
+
+    return True
+
+
+class DateTimeJSONEncoder(json.JSONEncoder):
+    """Encode python objects.
+
+    Additionally add encoding for datetime objects as isoformat.
+    """
+
+    def default(self, o):  # pylint: disable=E0202
+        """Implement encoding logic."""
+        if isinstance(o, datetime):
+            return o.isoformat()
+        return super().default(o)
+
+
+class KafkaManager:
+    """Define a manager to buffer events to Kafka."""
+
+    def __init__(
+            self,
+            hass,
+            ip_address,
+            port,
+            topic,
+            entities_filter):
+        """Initialize."""
+        self._encoder = DateTimeJSONEncoder()
+        self._entities_filter = entities_filter
+        self._hass = hass
+        self._producer = AIOKafkaProducer(
+            loop=hass.loop,
+            bootstrap_servers="{0}:{1}".format(ip_address, port),
+            compression_type="gzip",
+        )
+        self._topic = topic
+
+    def _encode_event(self, event):
+        """Translate events into a binary JSON payload."""
+        state = event.data.get('new_state')
+        if (state is None
+                or state.state in (STATE_UNKNOWN, '', STATE_UNAVAILABLE)
+                or not self._entities_filter(state.entity_id)):
+            return
+
+        return json.dumps(
+            obj=state.as_dict(),
+            default=self._encoder.encode
+        ).encode('utf-8')
+
+    async def start(self):
+        """Start the Kafka manager."""
+        self._hass.bus.async_listen(EVENT_STATE_CHANGED, self.write)
+        await self._producer.start()
+
+    async def shutdown(self):
+        """Shut the manager down."""
+        await self._producer.stop()
+
+    async def write(self, event):
+        """Write a binary payload to Kafka."""
+        payload = self._encode_event(event)
+
+        if payload:
+            await self._producer.send_and_wait(self._topic, payload)

homeassistant/components/apache_kafka/manifest.json

@@ -0,0 +1,10 @@
+{
+  "domain": "apache_kafka",
+  "name": "Apache Kafka",
+  "documentation": "https://www.home-assistant.io/components/apache_kafka",
+  "requirements": [
+    "aiokafka==0.5.1"
+  ],
+  "dependencies": [],
+  "codeowners": []
+}

requirements_all.txt

@@ -150,6 +150,9 @@ aiohue==1.9.1
 # homeassistant.components.imap
 aioimaplib==0.7.15
 
+# homeassistant.components.apache_kafka
+aiokafka==0.5.1
+
 # homeassistant.components.lifx
 aiolifx==0.6.7