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
