Starting two instances at the same time can cause cloning of extensions repo to fail

[cmeury]

Expected Behavior

It is not immediately clear what the expectation should be; maybe the extensions repository could be cloned with a separate command, so the user can control the timing? Or some sort of simple locking mechanism (empty file in ~/local/share/tilt-dev))?

Current Behavior

Using a Tiltfile which loads extensions, starting two instance of Tilt can result in conflicts about cloning the extensions repository:

Tilt started on http://localhost:10350/
v0.32.4, built 2023-05-24
Serving embedded Tilt production web assets

Initial Build
Loading Tiltfile at: /home/cmeury/tmp/tilt-instance-test/Tiltfile
# cd .; git clone -- https://github.com/tilt-dev/tilt-extensions /home/cmeury/.local/share/tilt-dev/tilt_modules/github.com/tilt-dev/tilt-extensions
Cloning into '/home/cmeury/.local/share/tilt-dev/tilt_modules/github.com/tilt-dev/tilt-extensions'...
error: Untracked working tree file '.circleci/Dockerfile' would be overwritten by merge.
fatal: unable to checkout working tree
warning: Clone succeeded, but checkout failed.
You can inspect what was checked out with 'git status'
and retry with 'git restore --source=HEAD :/'

ERROR: extensionrepo default: download error: waiting 5s before retrying. Original error: exit status 128
ERROR: Traceback (most recent call last):
  /home/cmeury/tmp/tilt-instance-test/Tiltfile:1:1: in <toplevel>
Error: cannot load ext://secret: loading extension repo default: download error: waiting 5s before retrying. Original error: exit status 128

Steps to Reproduce

1. Create a Tiltfile with a single entry: load('ext://secret', 'secret_from_dict')
2. Run two instances of Tilt at the same time

   tilt up --debug --port 10350 > first.log &
   tilt up --debug --port 20350 > second.log &  
   

3. Check the log files for errors

Context

tilt doctor Output

Tilt: v0.32.4, built 2023-05-24
System: linux-amd64

About Your Use Case

Running two Tilt instances at the same time on CI; for separate environments.

[nicks]

good catch! ya, we should probably have some sort of file-based lock here 🤔

[nicks]

i've also been wondering if we should change the behavior slightly. rather than doing a git pull on every tilt up, maybe it should pin to the version of the extensions repo that came out when that version of tilt was released.

[cmeury]

@nicks That's also what we did in our workaround, just before starting the two instances:

git clone --depth 1 --branch v0.32.4 -- https://github.com/tilt-dev/tilt-extensions ~/.local/share/tilt-dev/tilt_modules/github.com/tilt-dev/tilt-extensions