Crossbar.io External Worker Configuration - crossbar

Question

I have been using crossbar for awhile and I love it. I have a question about the best way to run workers that will connect to an external router. I was using "crossbar start" and creating a config file that connected to the router and this worked great.
Recently my requirements have changed to where I would like to pass the router url and realm into the config file via environment variables. After trial and error I concluded that this was not possible with the current XBAR implementation.
I then looked at creating an application runner using the following where I retrieved the realm and the url from config vars
runner = ApplicationRunner(url=url, realm=realm)
runner.run(AppSession)
This works but I then noticed my server would go down periodically. After root causing, I realized that the reverse proxy was timing out the connection after 1 hour of inactivity. Looking at the server logs, I got the "onDisconnect" callback. Looking at the XBAR application runner documentation it states the following
This class is a convenience tool mainly for development and quick hosting
of WAMP application components.
I have my service running in a "runit" script as a Daemon. Some quick fixes I came up with are
Kill the runner and let the daemon restart the service
Explicitly perform the join process on any disconnects
All of these were starting to feel really hacky given the XBAR folks explicitly state that the ApplicationRunner is a development tool. Anyone know if there is something I can use other than an application runner OR some way I can get environment variables into the config.json file?
As a temporary workaround I am using sed. Here is my config file
{
"controller": {
},
"workers": [
{
"type": "container",
"options": {
"pythonpath": [".."]
},
"components": [
{
"type": "class",
"classname": "src.app_session.AppSession",
"realm": "%%%ROUTER_REALM%%%",
"transport": {
"type": "websocket",
"endpoint": {
"type": "tcp",
"host": "%%%ROUTER_HOST%%%",
"port": %%%ROUTER_PORT%%%
},
"url": "%%%ROUTER_PROTOCOL%%%://%%%ROUTER_HOST%%%/ws"
}
}
]
}
]
}
And my runit script is
#!/bin/bash
# Update the ROUTER config parameters
sed -i -e "s/%%%ROUTER_HOST%%%/${ROUTER_HOST}/g" /app/.crossbar/config.json
sed -i -e "s/%%%ROUTER_PORT%%%/${ROUTER_PORT}/g" /app/.crossbar/config.json
sed -i -e "s/%%%ROUTER_REALM%%%/${ROUTER_REALM}/g" /app/.crossbar/config.json
sed -i -e "s/%%%ROUTER_PROTOCOL%%%/${ROUTER_PROTOCOL}/g" /app/.crossbar/config.json
cat /app/.crossbar/config.json
cd /app/
exec crossbar start

Answer 1

There is indeed no mechanism with Crossbar.io to do what you want. From the side of the project there are no plans to implement this as a feature. We want to concentrate on the management API, which will enable to dynamically manage Crossbar.io.