KKoPV: /* Terminal 1 - Start subscriber */

2017-05-17T20:07:08Z

‎Terminal 1 - Start subscriber

KKoPV: Created page with "{{TOCright}}PVLng can listen to a MQTT broker running on any server.
MQTT is a machine-to-machine (M2M)/"Internet of Things" connectivity protocol. It was designe..."

2017-05-17T20:06:23Z

Created page with "{{TOCright}}PVLng can listen to a MQTT broker running on any server. <blockquote>MQTT is a machine-to-machine (M2M)/"Internet of Things" connectivity protocol. It was designe..."

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{{TOCright}}PVLng can listen to a MQTT broker running on any server.

<blockquote>MQTT is a machine-to-machine (M2M)/"Internet of Things" connectivity protocol. It was designed as an extremely lightweight publish/subscribe messaging transport. It is useful for connections with remote locations where a small code footprint is required and/or network bandwidth is at a premium. -- [http://mqtt.org/ MQTT]</blockquote>

PVLng scripts can send to any MQTT broker.

== Setup your own mosquitto broker ==

sudo apt-get update
sudo apt-get install mosquitto

If you run the PVLng scripts also on this host or on remote equipment running the scripts only you need only the clients scripts

sudo apt-get update
sudo apt-get install mosquitto-clients

== Configure MQTT broker ==

Put the following into <tt>/etc/mosquitto/conf.d/local.conf</tt>

cat <<EOT | sudo tee /etc/mosquitto/conf.d/local.conf
log_type error
log_type warning
log_type notice
log_type information
connection_messages true
log_timestamp true
EOT

And restart

sudo /etc/init.d/mosquitto restart

Test your broker best with 2 terminals

=== Terminal 1 - Start subscriber ===

Wait for 1 message, print verbose message and exit

# mosquitto_sub -d -v -i test-subscriber -t test -c -C 1
Client test-subscriber sending CONNECT
Client test-subscriber received CONNACK
Client test-subscriber sending SUBSCRIBE (Mid: 1, Topic: test, QoS: 0)
Client test-subscriber received SUBACK
Subscribed (mid: 1): 0

=== Terminal 2 - Publish a zero length test message ===

# mosquitto_pub -d -n -i test-publisher -h localhost -t test
Client test-publisher sending CONNECT
Client test-publisher received CONNACK
Client test-publisher sending PUBLISH (d0, q0, r0, m1, 'test', ... (0 bytes))
Client test-publisher sending DISCONNECT

=== Terminal 1 - Received the message? ===

...
Client test-subscriber received PUBLISH (d0, q0, r0, m0, 'test', ... (0 bytes))
test (null)
Client test-subscriber sending DISCONNECT

== Run PVLng MQTT subscriber ==

The script is <tt>tools/mqtt-subscribe.sh</tt>

Start it at reboot via cron

cat <<EOT | sudo tee /etc/cron.d/mqtt-subscribe
# MQTT listener, wait for mosquitto broker
@reboot root sleep 60 && /path/to/PVLng/tools/mqtt-subscribe.sh start >/dev/null
# And check at least each hour
0 * * * * root /path/to/PVLng/tools/mqtt-subscribe.sh start >/dev/null
EOT

Check for safety reasons each hour.

To store data into PVLng database send a message to topic

pvlng/<API key>/data/<Channel GUID>

== Configure PVLng scripts ==

The scripts check for configured MQTT broker and use it, otherwise the default curl method is used as before.

You need only set the MQTT broker in <tt>PVLng.conf</tt> and uncomment the line.

##############################################################################
### Send to mosquitto broker running on $mosquittoServer
##############################################################################
### <Sever>[:<port>]
#mosquittoServer=$PVLngDomain:1883

If you test your scripts and send data, you can watch the stream in a terminal with

mosquitto_sub -v -t pvlng/+/data/#

This will give you something like this (2 temperature sensors)

pvlng/df9adc61-e81b-1e12-8fc7-8a1f000a3025/data/72f9-9c42-36c5-c2af-3c01-cd95-67a1-98d1 {"data":"29.5","timestamp":"1495051260"}
pvlng/df9adc61-e81b-1e12-8fc7-8a1f000a3025/data/bef9-6e8b-29a1-15a3-4100-58d2-69b8-3bdb {"data":"24.1875","timestamp":"1495051260"}

[[Category:Software]]

@@ Line 38: / Line 38: @@
 Wait for 1 message, print verbose message and exit
-  # mosquitto_sub -d -v -i test-subscriber -t test -c -C 1
+  # mosquitto_sub -d -v -i test-subscriber -t test -C 1
   Client test-subscriber sending CONNECT
   Client test-subscriber received CONNACK

MQTT - Revision history

KKoPV: /* Terminal 1 - Start subscriber */

KKoPV: Created page with "{{TOCright}}PVLng can listen to a MQTT broker running on any server. MQTT is a machine-to-machine (M2M)/"Internet of Things" connectivity protocol. It was designe..."

KKoPV: Created page with "{{TOCright}}PVLng can listen to a MQTT broker running on any server.
MQTT is a machine-to-machine (M2M)/"Internet of Things" connectivity protocol. It was designe..."