LetsTrust TPM SLB 9670VQ2.0 or SLB 9670XQ2.0?

By Maximilian Batz | 2019-06-11

A customer approached us about the difference between SLB 9670VQ2.0 and SLB 9670XQ2.0. VQ has a standard temperature range of (-20 .. +85°C), and XQ is the enhanced temperature range version (-40 .. + 85°C). As the Raspberry Pi itself has a standard temperature range, we use the VQ version on the LetsTrust TPM.

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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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MQTT Topic Tree Design best practices, tips & examples

By Maximilian Batz | 2019-05-29

Generic MQTT Background With MQTT the sender and receiver are not aware of each other – the broker handles the messaging. This allows the messages to be separated in space, time, and intensity. The sender can send at the speed it wants, and the time it wants. The receiver can pick up the messages at…

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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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envoy serving a static response

By Maximilian Batz | 2019-05-20

Besides routing and redirecting you can serve static responses with Envoy. In this case I want to serve a forbidden response (403) route_config:   virtual_hosts:   – name: picockpit     domains: [“picockpit.local:443”, “picockpit.local”]     routes:       – match: { prefix: “/demo” }         direct_response:           status: 403           body:             inline_string: “Forbidden.”        – match: {prefix: “/”}         route: {cluster: target_picockpit} It can also serve…

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Python Paho MQTT client self-signed certificates websockets, howto

By Maximilian Batz | 2019-05-19

Using Paho in Python with websockets and self-signed certificates for a https:// websocket connection has a couple of pitfalls, so I’m addressing this with some sample code here: import ssl import time import paho.mqtt.client as mqtt class PCPMQTTClient:     def on_connect(self, client, userdata, flags, rc):         self.connection_status = rc         if rc == 0:             self.connected_flag = True             self.connection_error_flag…

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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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