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Update page 'Message Queue Endpoint'

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Auke Sytsma 2020-03-01 11:49:06 +00:00
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Message-Queue-Endpoint.md
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@ -58,30 +58,29 @@ First, we will create a MQTT client to connect to the FarmMaps MQTT broker:
from farmmaps import mqtt from farmmaps import mqtt
#MQTT connection settings #MQTT connection settings
CLIENT_ID = 'trekkerdata' CLIENT_ID = '<your client id>'
USER = "trekkerdata" USER = "<your username>"
PWD = "<your password here>" PWD = "<your password here>"
HOST = "farmmaps.awtest.nl" HOST = "farmmaps.awacc.nl"
PORT = 1883 PORT = 1883
KEEPALIVE = 60 KEEPALIVE = 60
TOPIC = "trekkerdata/sensors" TOPIC = "<company-name>/<topic-name>"
#set up MQTT client #set up MQTT client
mqtt_client = mqtt.create_client(CLIENT_ID, USER, PWD, HOST, PORT, KEEPALIVE) mqtt_client = mqtt.create_client(CLIENT_ID, USER, PWD, HOST, PORT, KEEPALIVE)
``` ```
### Preparing your data as a protobuf message
### Example: Pushing Live Tractor Data
To create messages and connect to the broker we will need the following settings:
#### Preparing your data as a protobuf message
Farmmaps uses protobuf to specify a structure for the messages published in MQTT. Farmmaps uses protobuf to specify a structure for the messages published in MQTT.
Protobuf provides a fast way of serializing and unserializing objects, reducing bandwith usage.
More information on protobuf can be found at [Google Developer Documentation](https://developers.google.com/protocol-buffers/docs/overview). More information on protobuf can be found at [Google Developer Documentation](https://developers.google.com/protocol-buffers/docs/overview).
Python objects can easily be converted to protobuf messages and back (when recieving messages from the broker). Python objects can easily be converted to protobuf messages and back (when recieving messages from the broker).
The message structure for the data can be found in `farmmaps/farmmaps.proto`, and is shown below: The message structure for the data can be found in `farmmaps/farmmaps.proto`, and is shown below.
The main message is the Datapoint object, containing time, location, machine-id and a reference to metadata.
Then, there is a `sensors` parameter, which holds a dictionary of `SensorType` objects.
Each `SensorType` holds a key and a value, where the key identifies the Sensortype, and the value is the value of the sensor.
Finally, there's an optional `metadata_url` parameter that specifies where FarmMaps can get metadata.
This is data that specifies how the values for each sensortype are to be interpreted.
``` ```
syntax = "proto2"; syntax = "proto2";
@ -154,6 +153,8 @@ for key, value in sensordata.items():
In case you want to modify the structure of the object, the `.proto` can be modified, and the python module needs to be regenerated. In case you want to modify the structure of the object, the `.proto` can be modified, and the python module needs to be regenerated.
For now, we'll stick with the pregenerated protobuf class: ` For now, we'll stick with the pregenerated protobuf class: `
### Example: Pushing Live Tractor Data
To create messages and connect to the broker we will need the following settings: