I'm following heroku's post including this specific section. If I make a noop change and I'm running a new deploy, the bot responds. But then after some time, I see bot stops responding:
Is it possible this an issue with the starbot code not maintaining an open connection? How can I diagnosis this?
Are you using a vanilla starbot with no other modifications? Your question is unclear.
Some possible solutions for you, in no particular order:
1) Try running starbot locally and see if it maintains an open connection.
2) Try running starbot on a VPS or some other hosting platform and see if it maintains an open connection.
3) starbot uses Slack JS as the library that handles the underlying Slack connection. It uses quite an old version (6.1.0 according to the package.json). It's possible that this could be the cause. (The current version is 11.0.2.) You could try running a forked version of starbot with updated dependencies, although this might break the code.
4) Building on the previous point, rtm.client looks to not be part of the official API anymore. On the other hand, I looked at two other random projects on GitHub that implement this library (retrobot and accomplish), and both of those seem to use the rtm.client syntax, so I'm not able to tell without doing more research on the library. You could try to find a repository on GitHub that contains an already-written bot that uses the most recent version of the library in order to see how it looks/works.
5) You could write your own bot that leverages the Slack JS library directly.
6) You could write your own bot that leverages the official Slack SDK for NodeJS rather than the unofficial SlackJS.
