Sending data to Senfi

Senfi monitors and stores time series data from your existing systems. At the moment, Senfi provides a MQTT interface for receiving data from your systems. To start sending data to Senfi, you need to do the following:

1. Create an integration key in the CMS
2. Design and create a measurement in the CMS
3. Write a program to read from your system and send it to Senfi's MQTT endpoint

Create integration key

1. Login to the CMS
2. Go to the Integration tab
3. Click the + button to add a new integration key/secret pair
4. Note down the values of the Key (your integration key) and Secret (your integration secret)

Design/create measurement

The key to a successful integration is to have a well-designed measurement. So if you are not familiar with the concept of measurement/metric/tag, please read this section first.

1. When you are designing a measurement to represent your system, note down the metrics you want to capture.
2. Decide on a set of tags to use. Make sure that there is a combination of tags that will uniquely identify the unit/device/equipment that outputs those metrics.
3. Login to the CMS
4. Go to the Measurement tab
5. Click the + button to add a new measurement
6. Give the measurement a descriptive name. This will be shown to users of the dashboard.
7. Specify a measurement code. A measurement code is a unique identifier of this measurement. You can use a combination of lowercase alphanumeric characters and underscore.
   • The naming convention of a measurement code is as follows: <vendor>_<system>_<version>
   • For example: nest_thermostat_v1. If you make changes to the measurement (eg. adding or removing metrics), you should increment the version, eg. nest_thermostat_v2.
8. Add tags
9. Add metrics and specify the type of each metric
10. Save when done

Publish to MQTT

A typical integration follows this pattern:

 External system --> Your application --> Senfi MQTT endpoint

Either the external system you are monitoring pushes to your application, or your application polls the external system for its current values. Either way, once your application has the values of its measurement, you can prepare to send it to Senfi's MQTT endpoint.

MQTT Endpoint

Host

mqtt.senfi.io

Port

1883

Username

<Your integration key>

Password

<Your integration secret>

MQTT topic

ingestor/1/0/live/text/array/ems/<your integration key>/<your measurement code>

Message Format

Single measurement

 {
   "data": [
     {
       "tm_source": xxxxxxxxxx,
       "site_id" xxxxxxxx,
       "tag1": "xxxxxxxx",
       "tag2": "xxxxxxxx",
       "metric1": xxxxxxxxx,
       "metric2": xxxxxxxxx
       ...
     }
 }

Multiple measurements

 {
   "data": [
     {
       "tm_source": xxxxxxxxxx,
       "site_id" xxxxxxxx,
       "tag1": "xxxxxxxx",
       "tag2": "xxxxxxxx",
       "metric1": xxxxxxxxx,
       "metric2": xxxxxxxxx
       ...
     },
     {
       "tm_source": xxxxxxxxxx,
       "site_id" xxxxxxxx,
       "tag1": "xxxxxxxx",
       "tag2": "xxxxxxxx",
       "metric1": xxxxxxxxx,
       "metric2": xxxxxxxxx,
       ...
     }
   ]
 }

You must indicate which Site the measurement is meant for. Hence, you need to include the site ID (site_id) in your MQTT message. If your measurement has other tags, you must send them in the message as well.

You can take a look at this GitHub repository for a sample application to send data to Senfi's MQTT endpoint.

Publishing Strategy

You can either choose to publish data to Senfi regularly (eg. every second), or only do so upon change in the metrics. In practice, it is recommended that you publish regularly. This is so that the system is able to tell when data has stopped coming in.

In addition, you can choose to batch the sending of measurements to Senfi. For example, collect 50 measurements and then publish it in a single message. This may be useful if you have fast changing metrics. However, note that tm_source should represent when the measurement is sampled and not when it is sent.