Introduced Telegraf to take readings and push to InfluxDB cloud

Change-type: minor
Signed-off-by: Chris Crocker-White <chriscw@balena.io>

docker-compose.yml

@@ -28,3 +28,9 @@ services:
       - 'sense-data:/data'
     depends_on:
      - influxdb
+  telegraf:
+    build: ./telegraf
+    restart: always
+    depends_on:
+      - influxdb
+      - sensor

sensor/Dockerfile.template

@@ -14,7 +14,7 @@ WORKDIR /usr/src/app/bsec_bme680_linux
 RUN chmod +x make.sh
 RUN ./make.sh
 
-RUN pip install smbus influxdb
+RUN pip install smbus
 
 WORKDIR /usr/src/app
 COPY ./scripts ./scripts

sensor/entry.sh

@@ -3,4 +3,4 @@ mkdir -p /data/sensor
 touch /data/sensor/bsec_iaq.state
 cp -n /usr/src/app/bsec_bme680_linux/bsec_iaq.config /data/sensor/bsec_iaq.config
 
-python /usr/src/app/scripts/take_measurement.py
+python /usr/src/app/scripts/sensor.py

sensor/scripts/sensor.py

@@ -0,0 +1,110 @@
+# This script detects for the presence of either a BME680 sensor on the I2C bus or a Sense HAT
+# The BME680 includes sensors for temperature, humidity, pressure and gas content
+# The Sense HAT does not have a gas sensor, and so air quality is approximated using temperature and humidity only.
+
+import sys
+import time
+import smbus
+import os
+import json
+
+from hts221 import HTS221
+from bme680 import BME680
+from http.server import HTTPServer, BaseHTTPRequestHandler
+
+class balenaSense():
+    readfrom = 'unset'
+    bus = smbus.SMBus(1)
+
+    def __init__(self):
+        # First, check to see if there is a BME680 on the I2C bus
+        try:
+            self.bus.write_byte(0x76, 0)
+        except IOError:
+            print('BME680 not found on 0x76, trying 0x77')
+        else:
+            self.readfrom = 'bme680primary'
+
+        # If we didn't find it on 0x76, look on 0x77
+        if self.readfrom == 'unset':
+            try:
+                self.bus.write_byte(0x77, 0)
+            except IOError:
+                print('BME680 not found on 0x77')
+            else:
+                self.readfrom = 'bme680secondary'
+
+
+        # If no BME680, is there a Sense HAT?
+        if self.readfrom == 'unset':
+            try:
+                self.bus.write_byte(0x5F, 0)
+            except:
+                print('Sense HAT not found')
+            else:
+                self.readfrom = 'sense-hat'
+                print('Using Sense HAT for readings (no gas measurements)')
+
+                # Import the sense hat methods
+                import sense_hat_air_quality
+
+                self.sensor = HTS221()
+        else:
+                print('Using BME680 for readings')
+
+                # Import the BME680 methods
+                self.sensor = BME680(self.readfrom)
+
+
+        # If this is still unset, no sensors were found; quit!
+        if self.readfrom == 'unset':
+            print('No suitable sensors found! Exiting.')
+            sys.exit()
+
+    def sample(self):
+        if self.readfrom == 'sense-hat':
+            return self.apply_offsets(sense_hat_air_quality.get_readings(self.sensor))
+        else:
+            return self.apply_offsets(self.sensor.get_readings(self.sensor))
+
+
+    def apply_offsets(self, measurements):
+        # Apply any offsets to the measurements before storing them in the database
+        if os.environ.get('BALENASENSE_TEMP_OFFSET') != None:
+            measurements[0]['fields']['temperature'] = measurements[0]['fields']['temperature'] + float(os.environ['BALENASENSE_TEMP_OFFSET'])
+
+        if os.environ.get('BALENASENSE_HUM_OFFSET') != None:
+            measurements[0]['fields']['humidity'] = measurements[0]['fields']['humidity'] + float(os.environ['BALENASENSE_HUM_OFFSET'])
+
+        if os.environ.get('BALENASENSE_ALTITUDE') != None:
+            # if there's an altitude set (in meters), then apply a barometric pressure offset
+            altitude = float(os.environ['BALENASENSE_ALTITUDE'])
+            measurements[0]['fields']['pressure'] = measurements[0]['fields']['pressure'] * (1-((0.0065 * altitude) / (measurements[0]['fields']['temperature'] + (0.0065 * altitude) + 273.15))) ** -5.257
+
+        return measurements
+
+
+
+class balenaSenseHTTP(BaseHTTPRequestHandler):
+    def _set_headers(self):
+        self.send_response(200)
+        self.send_header('Content-type', 'text/html')
+        self.end_headers()
+
+    def do_GET(self):
+        self._set_headers()
+        measurements = balenasense.sample()
+        self.wfile.write(json.dumps(measurements[0]['fields']).encode('UTF-8'))
+
+    def do_HEAD(self):
+        self._set_headers()
+
+
+# Start the server to answer requests for readings
+balenasense = balenaSense()
+
+while True:
+    server_address = ('', 80)
+    httpd = HTTPServer(server_address, balenaSenseHTTP)
+    print('Sensor HTTP server running')
+    httpd.serve_forever()

telegraf/Dockerfile.template

@@ -0,0 +1,10 @@
+FROM balenalib/%%BALENA_MACHINE_NAME%%
+
+RUN curl -o /tmp/telegraf.deb https://dl.influxdata.com/telegraf/releases/telegraf_1.11.0-1_armhf.deb
+RUN dpkg -i /tmp/telegraf.deb && rm /tmp/telegraf.deb
+
+COPY telegraf.conf /etc/telegraf/telegraf.conf
+COPY entry.sh /entry.sh
+RUN chmod +x /entry.sh
+
+CMD /entry.sh

telegraf/entry.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+if [[ -z $INFLUX_TOKEN || -z $INFLUX_ORG || -z $INFLUX_BUCKET ]]; then
+  echo 'One or more InfluxDB variables are undefined - not using cloud'
+  sed -i '/influxdb_v2/,/bucket/ s/^#*/#/' /etc/telegraf/telegraf.conf
+else
+  echo 'InfluxDB variables are defined - using cloud'
+  sed -i '/influxdb_v2/,/bucket/ s/^##*//' /etc/telegraf/telegraf.conf
+fi
+
+telegraf

telegraf/telegraf.conf

@@ -0,0 +1,34 @@
+[global_tags]
+  balena_sense_id = "$BALENASENSE_ID"
+
+[agent]
+  interval = "10s"
+  round_interval = true
+  metric_batch_size = 1000
+  metric_buffer_limit = 10000
+  collection_jitter = "0s"
+  flush_interval = "10s"
+  flush_jitter = "0s"
+  debug = false
+  quiet = false
+  omit_hostname = false
+
+[[outputs.influxdb]]
+  urls = ["http://influxdb:8086"]
+  database = "balena-sense"
+  timeout = "1s"
+
+[[outputs.influxdb_v2]]
+  urls = ["https://us-west-2-1.aws.cloud2.influxdata.com"]
+  token = "$INFLUX_TOKEN"
+  organization = "$INFLUX_ORG"
+  bucket = "$INFLUX_BUCKET"
+
+[[inputs.http]]
+  urls = [
+    "http://sensor"
+  ]
+
+  timeout = "1s"
+  data_format = "json"
+  name_override = "balena-sense"