Publisher MQTT clients to provide data to a broker

Used for replaying data acquired by sensors or to bridge data from another broker.

Configuration File

The application expects YAML configuration files to specify the MQTT connection properties where to publish the data and the source of the data to be published. By default the application uses the config.yaml under the config/ folder for publishing data from a folder, and config_dev_pub.yaml for publishing data from a broker.

MQTT connection properties

In both configuration files you can use the top level broker node where you can specify the host, port, authentication credentials (can be empty), the topic where to publish, and the associated quality-of-service (QoS). Example of such configuration:

broker:
  host: "127.0.0.1"
  port: 1883
  clientId: "virtualProvider"
  authentication:
    username:
    password:
  topics:
      - topic: "my/test/topic1"
        qos: 2 # 0 - AT_MOST_ONCE  | 1 - AT_MOST_ONCE | 2 - EXACTLY_ONCE
sourceFolder: "data"
delay: 30 # seconds

Data Sources

To configure a folder as a data source use the top level sourceFolder and delay nodes to define the path to the folder and the delay interval in seconds between published files from the folder.

To configure a broker as a data source use the top level sourceBroker node which uses the same key:values properties as the broker node described above. In this case, one could subcribe to multiple topics as sources of data using:

sourceBroker:
  host: "127.0.0.1"
  port: 1883
  clientId: "bridgeProvider"
  authentication:
    username:
    password:
  topics:
      - topic: "my/test/topic1"
        qos: 2 
      - topic: "my/test/topic2"
        qos: 2
    # Wildcard Alternative:
    # - topic: "my/test/topic#"
    #    qos: 2

Docker Build and Execution

docker build -t publisher .
docker run publisher:latest

To customize configuration parameters pass the absolut path of the YAML configuration file ($PATH_TO_YAML) as argument in the docker command:

docker run -v $PATH_TO_YAML:/etc/publisher/config.yaml publisher:latest

To mount a different data folder ($PATH_TO_DIR) override the following directory as argument in the docker command:

docker run -p 9091:9091 -v $PATH_TO_DIR:/data publisher:latest