Example Using InfluxDB

This is a basic example to forward data to an InfluxDB database. Note this only covers a skeleton to start building your own application.

Prerequisites

The RPICT series board must output as CSV for this work.

Document edited using influxdb version 1.2 and python-influxdb version 4.0.

Installation

Server side hosting InfluxDB

Install InfluxDB and Chronograf as recommended. This link provides compiled executables.

Github link is here.

We will call this server hostname myserver for the rest of our example below.

Raspberrypi side

Install the python biding to influxdb. Available from github here.

Do not be tempted by using apt-get install! This installs an outdated version. Use pip or download the package from github and install using

sudo setup.py install

Check version using

python
import influxdb
print influxdb.__version__

Also install python serial if not done already.

sudo apt-get install python-serial

Testing

Use some of the example from influxdb documentation to test the correct communication between the server and raspberrypi.

Also make sure you can access Chronograf by going to

http://myserver:8888

Create Database

For our example we need to create a database within influxdb. We propose two way to perform this.

with curl
From a terminal on the influxdb hosting server one can issue the command below:

$ curl -i -XPOST http://localhost:8086/query --data-urlencode "q=CREATE DATABASE mydb"

with python
Alternatively from the raspberrypi itself the database can be created as follow

$ python
>>> from influxdb import InfluxDBClient
>>> client = InfluxDBClient('myserver', 8086, 'root', 'root', 'mydb')
>>> client.create_database('mydb')

Python Script

The python script below should be a good starting point to forward any RPICT series data to influxdb.

Copy the content into a file on the raspberrypi and make it executable:

$ chmod 755 InfluxDB_forward.py

Make sure you modify the head parameters first.

#!/usr/bin/python
import time
import datetime


serial_port = "/dev/ttyAMA0" # or "/dev/ttyS0"
baud = 38400

host = 'myserver'
port = 8086
DBNAME = 'mydb'
USER = 'root'
PASSWORD = 'root'

import serial
ser = serial.Serial(serial_port, baud, timeout=1)

from influxdb import InfluxDBClient
client = InfluxDBClient(host, port, USER, PASSWORD, DBNAME)

try:
       while 1:
                response = ser.readline()
                Z = response.split(",")
                if len(Z)>=2:
                        now = datetime.datetime.today()
                        i = 0
                        points = []
                        for z in Z:
                                i += 1
                                point = {
                                        "measurement":'ch%02d'%i,
                                        "time": 1000000000*int(now.strftime('%s')),
                                        "fields": {
                                                "value":float(Z[0])
                                        }
                                }
                                points.append(point)

                        client.write_points(points)

except KeyboardInterrupt:
       ser.close()