feat: add flag for router IP local run

[joshua-mo-143]

Reference: issue #350

Summary:

• adds local_ip_address crate to be able to grab local router IP
• add new flag --router_ip to be able to use router IP instead of localhost, which allows other devices on the network to access the local deployment.
• relevant testing has been added to account for new feature

Notes:
local_ip_address was added for this feature implementation as it looks to be a stable crate that doesn't appear to be going inactive any time soon and appears to work across OSes with no code change required (tested using Ubuntu and Win11). In the event that it does (or there's some breaking issue that renders it unusable), it looks like a method would have to be implemented per OS to get the router IP.

Windows users who are using this flag in Bash/WSL may have problems getting other devices to get this to work if they are not aware of the fact that there are extra steps¹ required to be able to connect external devices to a locally deployed run in Bash/WSL due to the fact it uses the WSL virtual ethernet. Not a huge problem as it seems most people who use shuttle are currently running Linux, but it's something to keep in mind should any issues regarding this pop up.

The new test also uses the same example as one of the other tests (the "hello world" Rocket example), which may or may not break the tests. Not entirely sure because trying to run all integration tests is broken on my laptop due to memory issues, but although the test passes in isolation it's probably something to be aware of.

Footnotes

1. (https://learn.microsoft.com/en-us/windows/wsl/networking) ↩

[chesedo]

Nice, thanks for this @joshua-mo-143!

I'm wondering, won't binding to the address 0.0.0.0 be enough? Then the local_ip crate won't be needed and I would expect users to know how to get their address on the network if they want to test from other devices.

[joshua-mo-143]

Ah that makes a lot more sense, I didn't realise you could bind it to 0.0.0.0 - that would probably be more optimal since it eliminates the need to add a dependency and would eliminate WSL-specific issues which would be helpful for compatibility. Looks like I still have a lot to learn about using IPs and networking 😅

[oddgrd]

This looks cool Josh! It looks like you need to do a cargo fmt to make the CI happy, and maybe clippy. And dont worry about squashing commits, we'll do that when we merge. 🙂

[chesedo]

So sorry for another round of changes, but it is small 😄

[chesedo]

I'm not sold on the name, but can't think of anything better either 😅

[joshua-mo-143]

The only other things I can really think of are network or local_ip, but yeah to be honest I'm not huge on either of them and router_ip is not really that descriptive

[joshua-mo-143]

Honestly tempted to use network or lan as the flag since router_ip or use_router_ip isn't technically accurate anymore, what do you think?

[chesedo]

Hmm, I was thinking more like 'host' but don't like it. How about external?

[joshua-mo-143]

Ok that sounds like a good idea, I'll add that in then

[joshua-mo-143]

It's ok, I appreciate the checks to make sure everything is optimised before pushing through - I'm personally more concerned about solving the circleCI cargo shuttle test failing since that seems to be a pressing issue. It looks like it's running into the same issue I had in local which is that it failed on trying to wait for start up

[chesedo]

The "rocket/postgres" has intermittent issues starting up, so don't worry about it too much. If your new test works locally then I'm fine merging this even if the other tests fail on the CI

[oddgrd]

Thanks a lot Josh, this is a really useful feature! 🚀