Attempt to randomize port on startup if default is unavailable

[rpocase]

When switching between tilt projects that contain tilt wrappers (e.g. make tilt) I'll often hit issues with port allocation issues. My options tend to be:

• stop one project (which could be costly to start back up)
• fall back to running tilt directly (could need to run several setup tasks directly)
• assign tilt ports in each project (or at least allow setting them via ENV_VAR)

I'd like for tilt to have a (optional?) method to randomize port allocation if the default port is in use.

An alternative I've thought about is a tilt daemon/manager that is project context aware. Tilt could host its web-ui on the same port but provide subpaths for components running under different Tiltfile contexts (e.g. localhost:10350/project1, localhost:10350/project2).

[wu-victor]

Thanks @rpocase for the issue. Indeed folks often Tilt at the same time in multiple projects at that same time.

[nicks]

fwiw, i've been hitting this a lot myself recently. I too go back and forth if I actually want to have two separate tilt instances to keep track of, or rather if I want them to "join" together

The first one has a simpler mental model, but the second one seems more useful (particularly if we're able to crack the nut of sidebar organization when you have a lot of services)