synctl to show status and listening ports

[romainbou]

When running synctl start the server starts without letting us know that it's listening on TCP ports and which ones.
I'd find it helpful if synctl recalls the server's configured listening TCP ports when it starts.

I'd like to know what you think, whether it can become too verbose?

suggested behavior:

> synctl start
[...]
started synapse.app.homeserver('homeserver.yaml')
Listening on ::1:8008
Listening on 127.0.0.1:8008

> synctl status
Synapse is running with PID: 1337
Listening on ::1:8008
Listening on 127.0.0.1:8008

> synctl stop
> synctl status
No running Synapse process found

[richvdh]

I think that it would be hard to do without tying synctl quite closely to the format of the synapse config file. There are more edge cases than you might imagine.

[romainbou]

Surely. Maybe it doesn't have to cover all kinds of listener config?

I think it's informative for simple cases and basic homeservers. Helping people used to typical HTTP services logging the listening ports.

Advanced users can always refer to the config. As long as it doesn't create confusion by omission of advanced cases.

I'm happy to make a PR and update the message for clarity. Without overcomplicating synctl. Or is it superfluous? Let me know what you think.

[richvdh]

I think there's a danger of causing confusion by assuming that synapse is doing exactly what the config says. For example, if the config file is changed after synapse starts, your synctl would report incorrect status.

An alternative approach might be for synapse to provide an interface to return its status (which synctl status could return). Honestly though, I think it's more work than it's worth.

[romainbou]

All right then let's cross off synctl status until synapse has a status interface.
How about keeping it for synctl start since it reads the config when synapse does too, do you see other dangers?