.. _mqtt-publisher-sample:
MQTT Publisher
##############
Overview
********
`MQTT <http://mqtt.org/>`_ (MQ Telemetry Transport) is a lightweight
publish/subscribe messaging protocol optimized for small sensors and
mobile devices.
The Zephyr MQTT Publisher sample application is a MQTT v3.1.1
client that sends MQTT PUBLISH messages to a MQTT broker.
See the `MQTT V3.1.1 spec`_ for more information.
.. _MQTT V3.1.1 spec: http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/mqtt-v3.1.1.html
The source code of this sample application can be found at:
:file:`samples/net/mqtt_publisher`.
Requirements
************
- Linux machine
- Freedom Board (FRDM-K64F)
- Mosquitto server: any version that supports MQTT v3.1.1. This sample
was tested with mosquitto 1.3.4.
- Mosquitto subscriber
- LAN for testing purposes (Ethernet)
Build and Running
*****************
Currently, this sample application only supports static IP addresses.
Open the :file:`src/config.h` file and set the IP addresses according
to the LAN environment.
Alternatively, set the IP addresses in the :file:`prj_frdm_k64f.conf` file.
This file :file:`src/config.h` also contains some variables that may be changed:
MQTT broker TCP port:
.. code-block:: c
#define SERVER_PORT 1883
Application sleep time:
.. code-block:: c
#define APP_SLEEP_MSECS 500
Application RX and TX timeout:
.. code-block:: c
#define APP_TX_RX_TIMEOUT 300
Max number of connection tries:
.. code-block:: c
#define APP_CONNECT_TRIES 10
Max number of MQTT PUBLISH iterations:
.. code-block:: c
#define APP_MAX_ITERATIONS 5
MQTT Client Identifier:
.. code-block:: c
#define MQTT_CLIENTID "zephyr_publisher"
This sample application supports the IBM Bluemix Watson topic format that can
be enabled by changing the default value of APP_BLUEMIX_TOPIC from 0 to 1:
.. code-block:: c
#define APP_BLUEMIX_TOPIC 1
The Bluemix topic may include some parameters like device type, device
identifier, event type and message format. This application uses the
following macros to specify those values:
.. code-block:: c
#define BLUEMIX_DEVTYPE "sensor"
#define BLUEMIX_DEVID "carbon"
#define BLUEMIX_EVENT "status"
#define BLUEMIX_FORMAT "json"
On your Linux host computer, open a terminal window, locate the source code
of this sample application (i.e. :file:`samples/net/mqtt_publisher`) and type:
.. code-block:: console
$ make BOARD=frdm_k64f
Open another terminal window and type:
.. code-block:: console
$ sudo mosquitto -v -p 1883
Open another terminal window and type:
.. code-block:: console
$ mosquitto_sub -t sensors
Sample output
=============
This is the output from the FRDM UART console, with:
.. code-block:: c
#define APP_MAX_ITERATIONS 5
.. code-block:: console
[dev/eth_mcux] [INF] eth_0_init: Enabled 100M full-duplex mode.
[dev/eth_mcux] [DBG] eth_0_init: MAC 00:04:9f:3e:1a:0a
[publisher:233] network_setup: 0 <OK>
[publisher:258] mqtt_init: 0 <OK>
[connect_cb:81] user_data: CONNECTED
[try_to_connect:212] mqtt_tx_connect: 0 <OK>
[publisher:276] try_to_connect: 0 <OK>
[publisher:285] mqtt_tx_pingreq: 0 <OK>
[publisher:290] mqtt_tx_publish: 0 <OK>
[publish_cb:149] <MQTT_PUBACK> packet id: 1888, user_data: PUBLISH
[publisher:295] mqtt_tx_publish: 0 <OK>
[publish_cb:149] <MQTT_PUBREC> packet id: 16356, user_data: PUBLISH
[publish_cb:149] <MQTT_PUBCOMP> packet id: 16356, user_data: PUBLISH
[publisher:300] mqtt_tx_publish: 0 <OK>
[publisher:285] mqtt_tx_pingreq: 0 <OK>
[publisher:290] mqtt_tx_publish: 0 <OK>
[publish_cb:149] <MQTT_PUBACK> packet id: 45861, user_data: PUBLISH
[publisher:295] mqtt_tx_publish: 0 <OK>
[publish_cb:149] <MQTT_PUBREC> packet id: 53870, user_data: PUBLISH
[publish_cb:149] <MQTT_PUBCOMP> packet id: 53870, user_data: PUBLISH
[publisher:300] mqtt_tx_publish: 0 <OK>
[publisher:285] mqtt_tx_pingreq: 0 <OK>
[publisher:290] mqtt_tx_publish: 0 <OK>
[publish_cb:149] <MQTT_PUBACK> packet id: 60144, user_data: PUBLISH
[publisher:295] mqtt_tx_publish: 0 <OK>
[publish_cb:149] <MQTT_PUBREC> packet id: 6561, user_data: PUBLISH
[publish_cb:149] <MQTT_PUBCOMP> packet id: 6561, user_data: PUBLISH
[publisher:300] mqtt_tx_publish: 0 <OK>
[publisher:285] mqtt_tx_pingreq: 0 <OK>
[publisher:290] mqtt_tx_publish: 0 <OK>
[publish_cb:149] <MQTT_PUBACK> packet id: 38355, user_data: PUBLISH
[publisher:295] mqtt_tx_publish: 0 <OK>
[publish_cb:149] <MQTT_PUBREC> packet id: 60656, user_data: PUBLISH
[publish_cb:149] <MQTT_PUBCOMP> packet id: 60656, user_data: PUBLISH
[publisher:300] mqtt_tx_publish: 0 <OK>
[publisher:285] mqtt_tx_pingreq: 0 <OK>
[publisher:290] mqtt_tx_publish: 0 <OK>
[publish_cb:149] <MQTT_PUBACK> packet id: 28420, user_data: PUBLISH
[publisher:295] mqtt_tx_publish: 0 <OK>
[publish_cb:149] <MQTT_PUBREC> packet id: 49829, user_data: PUBLISH
[publish_cb:149] <MQTT_PUBCOMP> packet id: 49829, user_data: PUBLISH
[publisher:300] mqtt_tx_publish: 0 <OK>
[disconnect_cb:101] user_data: DISCONNECTED
[publisher:304] mqtt_tx_disconnect: 0 <OK>
Bye!
The line:
.. code-block:: console
[try_to_connect:220] mqtt_connect: -5 <ERROR>
means that an error was detected and a new connect message will be sent.
The MQTT API is asynchronous, so messages are displayed as the callbacks are
executed.
This is the information that the subscriber will receive:
.. code-block:: console
$ mosquitto_sub -t sensors
DOORS:OPEN_QoS0
DOORS:OPEN_QoS1
DOORS:OPEN_QoS2
DOORS:OPEN_QoS0
DOORS:OPEN_QoS1
DOORS:OPEN_QoS2
DOORS:OPEN_QoS0
DOORS:OPEN_QoS1
DOORS:OPEN_QoS2
DOORS:OPEN_QoS0
DOORS:OPEN_QoS1
DOORS:OPEN_QoS2
DOORS:OPEN_QoS0
DOORS:OPEN_QoS1
DOORS:OPEN_QoS2
This is the output from the MQTT broker:
.. code-block:: console
$ sudo mosquitto -v
1485663791: mosquitto version 1.3.4 (build date 2014-08-17 00:14:52-0300) starting
1485663791: Using default config.
1485663791: Opening ipv4 listen socket on port 1883.
1485663791: Opening ipv6 listen socket on port 1883.
1485663797: New connection from 192.168.1.101 on port 1883.
1485663797: New client connected from 192.168.1.101 as zephyr_publisher (c1, k0).
1485663797: Sending CONNACK to zephyr_publisher (0)
1485663798: Received PINGREQ from zephyr_publisher
1485663798: Sending PINGRESP to zephyr_publisher
1485663798: Received PUBLISH from zephyr_publisher (d0, q0, r0, m0, 'sensors', ... (15 bytes))
1485663799: Received PUBLISH from zephyr_publisher (d0, q1, r0, m1888, 'sensors', ... (15 bytes))
1485663799: Sending PUBACK to zephyr_publisher (Mid: 1888)
1485663799: Received PUBLISH from zephyr_publisher (d0, q2, r0, m16356, 'sensors', ... (15 bytes))
1485663799: Sending PUBREC to zephyr_publisher (Mid: 16356)
1485663799: Received PUBREL from zephyr_publisher (Mid: 16356)
1485663799: Sending PUBCOMP to zephyr_publisher (Mid: 16356)
1485663800: Received PINGREQ from zephyr_publisher
1485663800: Sending PINGRESP to zephyr_publisher
1485663800: Received PUBLISH from zephyr_publisher (d0, q0, r0, m0, 'sensors', ... (15 bytes))
1485663801: Received PUBLISH from zephyr_publisher (d0, q1, r0, m45861, 'sensors', ... (15 bytes))
1485663801: Sending PUBACK to zephyr_publisher (Mid: 45861)
1485663801: Received PUBLISH from zephyr_publisher (d0, q2, r0, m53870, 'sensors', ... (15 bytes))
1485663801: Sending PUBREC to zephyr_publisher (Mid: 53870)
1485663801: Received PUBREL from zephyr_publisher (Mid: 53870)
1485663801: Sending PUBCOMP to zephyr_publisher (Mid: 53870)
1485663802: Received PINGREQ from zephyr_publisher
1485663802: Sending PINGRESP to zephyr_publisher
1485663802: Received PUBLISH from zephyr_publisher (d0, q0, r0, m0, 'sensors', ... (15 bytes))
1485663803: Received PUBLISH from zephyr_publisher (d0, q1, r0, m60144, 'sensors', ... (15 bytes))
1485663803: Sending PUBACK to zephyr_publisher (Mid: 60144)
1485663803: Received PUBLISH from zephyr_publisher (d0, q2, r0, m6561, 'sensors', ... (15 bytes))
1485663803: Sending PUBREC to zephyr_publisher (Mid: 6561)
1485663803: Received PUBREL from zephyr_publisher (Mid: 6561)
1485663803: Sending PUBCOMP to zephyr_publisher (Mid: 6561)
1485663804: Received PINGREQ from zephyr_publisher
1485663804: Sending PINGRESP to zephyr_publisher
1485663804: Received PUBLISH from zephyr_publisher (d0, q0, r0, m0, 'sensors', ... (15 bytes))
1485663805: Received PUBLISH from zephyr_publisher (d0, q1, r0, m38355, 'sensors', ... (15 bytes))
1485663805: Sending PUBACK to zephyr_publisher (Mid: 38355)
1485663805: Received PUBLISH from zephyr_publisher (d0, q2, r0, m60656, 'sensors', ... (15 bytes))
1485663805: Sending PUBREC to zephyr_publisher (Mid: 60656)
1485663805: Received PUBREL from zephyr_publisher (Mid: 60656)
1485663805: Sending PUBCOMP to zephyr_publisher (Mid: 60656)
1485663806: Received PINGREQ from zephyr_publisher
1485663806: Sending PINGRESP to zephyr_publisher
1485663806: Received PUBLISH from zephyr_publisher (d0, q0, r0, m0, 'sensors', ... (15 bytes))
1485663807: Received PUBLISH from zephyr_publisher (d0, q1, r0, m28420, 'sensors', ... (15 bytes))
1485663807: Sending PUBACK to zephyr_publisher (Mid: 28420)
1485663807: Received PUBLISH from zephyr_publisher (d0, q2, r0, m49829, 'sensors', ... (15 bytes))
1485663807: Sending PUBREC to zephyr_publisher (Mid: 49829)
1485663807: Received PUBREL from zephyr_publisher (Mid: 49829)
1485663807: Sending PUBCOMP to zephyr_publisher (Mid: 49829)
1485663808: Received DISCONNECT from zephyr_publisher
0829ddfe9a