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] ]
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 . |
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 to10
seconds.ping_delay
: Auto-ping delay before keep-alive timeout. Defaults to 1. Setting to0
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 tofalse
.auto_reconnect
: Enable or disable auto-reconnect if connectection with the broker is interrupted. Defaults tofalse
.reconnect_retries
: Maximum reconnection retries. Defaults to2
.reconnect_max_interval
: Maximum interval between 2 connection retry. Defaults to10
.
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