hbmqtt_sub¶

hbmqtt_sub is a command line MQTT client that subscribes to some topics and output data received from messages published.

Usage¶

hbmqtt_sub usage :

hbmqtt_sub --version
hbmqtt_sub (-h | --help)
hbmqtt_sub --url BROKER_URL -t TOPIC... [-n COUNT] [-c CONFIG_FILE] [-i CLIENT_ID] [-q | --qos QOS] [-d]
           [-k KEEP_ALIVE] [--clean-session] [--ca-file CAFILE] [--ca-path CAPATH] [--ca-data CADATA]
           [ --will-topic WILL_TOPIC [--will-message WILL_MESSAGE] [--will-qos WILL_QOS] [--will-retain] ]
           [--extra-headers HEADER]

Note that for simplicity, hbmqtt_sub uses mostly the same argument syntax as mosquitto_sub.

Options¶

`--version`	HBMQTT version information
`-h, --help`	Display `hbmqtt_sub` usage help
`-c`	Set the YAML configuration file to read and pass to the client runtime.
`-d`	Enable debugging informations.
`--ca-file`	Define the path to a file containing PEM encoded CA certificates that are trusted. Used to enable SSL communication.
`--ca-path`	Define the path to a directory containing PEM encoded CA certificates that are trusted. Used to enable SSL communication.
`--ca-data`	Set the PEM encoded CA certificates that are trusted. Used to enable SSL communication.
`--clean-session`
	If given, set the CONNECT clean session flag to True.
`-i`	The id to use for this client. If not given, defaults to `hbmqtt_sub/` appended with the process id and the hostname of the client.
`-k`	Set the CONNECT keep alive timeout.
`-n`	Number of messages to read before ending. Read forever if not given.
`-q, --qos`	Specify the quality of service to use for receiving messages. This QoS is sent in the subscribe request.
`-t`	Topic filters to subcribe.
`--url`	Broker connection URL, conforming to MQTT URL scheme.
`--will-topic`	The topic on which to send a Will, in the event that the client disconnects unexpectedly.
`--will-message`	Specify a message that will be stored by the broker and sent out if this client disconnects unexpectedly. This must be used in conjunction with `--will-topic`.
`--will-qos`	The QoS to use for the Will. Defaults to 0. This must be used in conjunction with `--will-topic`.
`--will-retain`	If given, if the client disconnects unexpectedly the message sent out will be treated as a retained message. This must be used in conjunction with `--will-topic`.
`--extra-headers`
	Specify a JSON object string with key-value pairs representing additional headers that are transmitted on the initial connection, but only when using a websocket connection

Configuration¶

If -c argument is given, hbmqtt_sub will read specific MQTT settings for the given configuration file. This file must be a valid YAML file which may contains the following configuration elements :

keep_alive : Keep-alive timeout sent to the broker. Defaults to 10 seconds.
ping_delay : Auto-ping delay before keep-alive timeout. Defaults to 1. Setting to 0 will disable to 0 and may lead to broker disconnection.
default_qos : Default QoS for messages published. Defaults to 0.
default_retain : Default retain value to messages published. Defaults to false.
auto_reconnect : Enable or disable auto-reconnect if connectection with the broker is interrupted. Defaults to false.
reconnect_retries : Maximum reconnection retries. Defaults to 2.
reconnect_max_interval : Maximum interval between 2 connection retry. Defaults to 10.

Examples¶

Examples below are adapted from mosquitto_sub documentation.

Subscribe with QoS 0 to all messages published under $SYS/:

hbmqtt_sub --url mqtt://localhost -t '$SYS/#' -q 0

Subscribe to 10 messages with QoS 2 from /#:

hbmqtt_sub --url mqtt://localhost -t /# -q 2 -n 10

Subscribe with QoS 0 to all messages published under $SYS/: over mqtt encapsulated in a websocket connection and additional headers:

hbmqtt_sub --url wss://localhost -t '$SYS/#' -q 0 --extra-headers '{"Authorization": "Bearer <token>"}'