This example shows how to create a basic connection to the Exosite Murano Platform using MQTT and the open source paho-mqtt library.
Note: A Murano account and product is required: http://info.exosite.com/platform-sign-up
License is BSD, Copyright 2018, Exosite LLC (see LICENSE file)
Tested on Ubuntu 17.10
Troubleshooting information and help can be in the Exosite Community Forum.
First install the paho-mqtt library and compile on your system. Ensure you've got git and a c compiler installed.
git clone https://github.com/eclipse/paho.mqtt.c.git
cd paho.mqtt.c
make
sudo make install
NOTE: Some errors may occur during installation.
Once the paho-mqtt library is installed you can go ahead and compile this example:
In order to use the activate and pubsub examples, you'll first need to set some #defines in the respective .c files.
Open the Murano Product web UI and click the link that the image (below) is pointing to. This copies the Murano Product hostname into your clipboard.
In both activate and pubsub examples, you will trim some characters from this URL to define the MQTT secure host to Murano.
Example using hostname mqtt://f5330e4s8cho0000.m2.exosite.io/:
#define ADDRESS "ssl://f5330e4s8cho0000.m2.exosite.io:8883"
NOTE: This example uses port 8883. If you changed this to 443 in your Murano Product Settings, then do so in the ADDRESS as well.
The example code in activate.c illustrates how to get a device provisioned onto your Murano Product and retrieve its secure token. The token printed in the output should be stored in non-volatile memory on your device. Once this token is retrieved/activated, it is used in all further connections to Murano.
First, edit the ADDRESS (described above) and ACTIVATE_TOPIC in activate.c. The <id> is typically your device serial number.
#define ADDRESS "ssl://<hostname>:<port>"
#define ACTIVATE_TOPIC "$provision/<id>"
Next, compile the activate binary.
make activate
Finally, execute the activate binary to retrieve your device's token.
Example:
$ make activate
gcc activate.c -Wall -g -lpaho-mqtt3cs -o activate
$ ./activate
connecting...
publishing activation request...
sleeping until murano responds with token...
Message with token value 1 delivery confirmed
Provisioning successful.
Murano token: Ed9GHsPnc2gyZsOFoShPhxj80sRlzH9E1vZCTK9y
The last line of output, above, contains the Murano token for further connections.
The example code in pubsub.c illustrates how to publish arbitrary data to your Murano Product's data_in resource while simultaneously monitoring all other Murano resources for new data.
First, specify the Murano token from the activate step and the same ADDRESS.
#define ADDRESS "ssl://<hostname>:<port>"
#define TOKEN "<MURANO_TOKEN>"
Next, compile the pubsub binary.
make pubsub
Finally, execute the pubsub binary.
In the example, below, randomized JSON objects are published to data_in and a message is received from the Murano Product resource data_out after a few seconds.
$ make pubsub
gcc pubsub.c -Wall -g -lpaho-mqtt3cs -o pubsub
$ ./pubsub
Message with delivery token 1 delivered: {"001": 8}
Message with delivery token 2 delivered: {"001": 87}
Message with delivery token 3 delivered: {"001": 10}
Message with delivery token 4 delivered: {"001": 21}
Message with delivery token 5 delivered: {"001": 27}
Message with delivery token 6 delivered: {"001": 49}
Message with delivery token 7 delivered: {"001": 10}
Message with delivery token 8 delivered: {"001": 10}
Message with delivery token 9 delivered: {"001": 19}
Message arrived
topic: $resource/data_out/1538080072997000
message: reboot
Message with delivery token 10 delivered: {"001": 47}
Message with delivery token 11 delivered: {"001": 48}
Message with delivery token 12 delivered: {"001": 60}
Message with delivery token 13 delivered: {"001": 97}
^C