I spent some time tonight deploying Docker and your code here. Everything is working like it should but I did wind up struggling with one part and I figured I'd share it here. Your bridge code is prepending a / to the MQTT namespace. As this is the first time I've touched any of these technologies I was unaware that this isn't really conventional. The test code I'm using from Mosquitto and Home-Assistant (and elsewhere) all use
topic/whatever, where mqtt-bridge uses
/topic/whatever which caused me no end of consternation in my testing. Once I figured that bit out it made a lot more sense and now everything is working like it should.
Anyway - WHAT A GREAT TOOL! This is going to be super helpful in working with the ESP8266 as I can skip a lot of screwing around with LAN communication to these devices and let the existing MQTT libraries handle all of that. Your code is going to save me a crapload of time and I really appreciate your work here.