VerneMQ how to disconnect clients forceably per command line

By Maximilian Batz | 2019-08-08

There is a command vmq-admin session show which will show you the currently connected clients: Unfortunately, this output is truncated for a total width of 80 characters (no matter how many would fit) and there is currently no indication that it is. See this VerneMQ Github issue: https://github.com/vernemq/vernemq/issues/1200 To disconnect clients you need the client_id…

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Changing the mountpoint on auth_on_register webhook for VerneMQ

By Maximilian Batz | 2019-06-09

It is possible to pass modifiers along with the “result”: “ok” return value of your webhook for VerneMQ. The official documentation of VerneMQ gives some examples for the syntax. changing the mountpoint It is also possible to change the mountpoint, however the client_id apparently has to be passed in as well! I have raised an…

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Debugging VerneMQ connection / authentication problems for dual authentication with webhooks and vmq_diversity

By Maximilian Batz | 2019-06-04

TL;DR https://github.com/vernemq/vernemq/blob/master/apps/vmq_diversity/src/vmq_diversity_plugin.erl includes a statement which will block authentication / authorization through any other channels if your Lua script returns “false”: will lead to: instead of trying other plugins, as you might have assumed! In order to avoid this problem, simply do not return anything from your Lua script, if you do not want to…

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VerneMQ: econnrefused & Webhook example

By Maximilian Batz | 2019-05-20

Webhooks activate webhooks like this in your vernemq.conf.local (.local when running on docker, so that settings at bottom of the file will persist): plugins.vmq_webhooks = on vmq_webhooks.js_auth_on_register.hook = auth_on_register vmq_webhooks.js_auth_on_register.endpoint = http://container_picockpit:1200/example/path Note that if your webhook is not accessible (econnrefused), the db based authentication will also fail … ! If you get errors like…

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VerneMQ Docker overwrites my configuration

By Maximilian Batz | 2019-05-19

Situation You edit vernemq.conf, only to find that your configuration is overwritten by VerneMQ on the next start (using the official Docker container). Specifically, the section with the listeners at the end of the file is “forced upon you”. Solution VerneMQ is started using a script (start_vernemq). The script can be seen here: https://github.com/vernemq/docker-vernemq/blob/master/bin/vernemq.sh The…

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envoy not connecting to VerneMQ for MQTT over websockets, error code 503

By Maximilian Batz | 2019-05-19

Some quick background information for anyone running into the same issues, and how to debug them. Error code 503 This is the error code I am getting: Error during WebSocket handshake: Unexpected response code: 503. Set envoy logging to debug Here’s my docker-compose.yaml for envoy: version: ‘3.7’ services:   envoy:     build:       context: ./       dockerfile: Dockerfile     container_name:…

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correct way to instantiate Paho Client in JavaScript for wss (secure websocket)

By Maximilian Batz | 2019-05-17

The Paho documentation is unfortunately quite fragmented at the moment, and some links on Eclipse’s website do not work. Here are some working links (as of 05/2019): https://www.eclipse.org/paho/clients/js/ https://www.eclipse.org/paho/files/jsdoc/index.html https://github.com/eclipse/paho.mqtt.javascript And here’s a fantastic website by Steve: http://www.steves-internet-guide.com/using-javascript-mqtt-client-websockets/ There is an important breaking change in the Paho namespace, where you will run into trouble using…

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