Fail the app when binding to a port fails

[laduke]

tokio is was eating the panics and continuing on
with no socket listening on 53

making tokio crash would take a bunch of rewrite,
i think, so i moved the bind calls out to a different fn

The error looks like this:

thread 'main' panicked at 'Could not bind TCP port 53. Are you root?', ~/repos/github.com/zerotier/zeronsd/src/server.rs:31:23
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

[erikh]

These are suggestions I have for the betterment of the user experience, I hope you agree they are worthwhile changes.

Thanks!

[erikh]

might be better to change the sig of the return value to return Result<Vec<_>, anyhow::Error> so the original error doesn't get swallowed.

[laduke]

Took a stab at that but then I'd have to change the signature Service::new and then of every test, so...
People running zeronsd tests can figure it out :)

[erikh]

I'm not sure that's the best way, but I won't argue with you. :P

[laduke]

Thanks. I couldn't get that to work for some reason and you motivated me to fix it.

Now it makes errors that look like this:

Error: Failed to bind TCP port 53

Caused by:
    Permission denied (os error 13)

Error: Failed to bind UDP port 53

Caused by:
    Address already in use (os error 48)

[erikh]

Glad to be of help! I hadn't used with_context() before. Neat call!

[CLAassistant]

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