[DO NOT MERGE] [API server] consistent module path of server and cli

[aylei]

close #4801

Tested manually, checked whether the module in current working dir is used:

# Note: avoid -e
$ pip install ".[all]"
$ sed -i "s/API_VERSION = '3'/API_VERSION = '9'/" sky/server/constants.py
$ sky api stop && sky api start

This branch, the installed module is used instead of current dir, which is expected:

$ sky api start
$ curl http://127.0.0.1:46580/api/health
{"status":"healthy","api_version":"3","commit":"296a22e868b9bdf1faccbe3effbfb858a5a05905-dirty","version":"1.0.0-dev0"}%

This branch, but launch with python -m sky.cli api start:

$ sky api start
# Both client and server are started using the same version from current dir, which is expected I think
$ curl http://127.0.0.1:46580/api/health
{"status":"healthy","api_version":"9","commit":"296a22e868b9bdf1faccbe3effbfb858a5a05905-dirty","version":"1.0.0-dev0"}%

Master branch, start raise an error, indicates the local dir is used:

sky.exceptions.ApiServerConnectionError: Could not connect to SkyPilot API server at http://127.0.0.1:46580. Please ensure that the server is running. Try: curl http://127.0.0.1:46580/api/health

During handling of the above exception, another exception occurred:

AssertionError: API server version mismatch when starting the server. Server version: 9 Client version: 3

Also tested the case that skyserver is not installed:

$ sky api start
Failed to connect to SkyPilot API server at http://127.0.0.1:46580. Starting a local server.
sky.exceptions.ApiServerConnectionError: Could not connect to SkyPilot API server at http://127.0.0.1:46580. Please ensure that the server is running. Try: curl http://127.0.0.1:46580/api/health

During handling of the above exception, another exception occurred:

RuntimeError: SkyPilot API server command skyserver is not available in PATH. Rerun `pip install -e .` to install the command.

Tested (run the relevant ones):

• Code formatting: bash format.sh
• Any manual or new tests for this PR (see above)
• All smoke tests: pytest tests/test_smoke.py
• Relevant individual smoke tests: pytest tests/test_smoke.py::test_fill_in_the_name
• Backward compatibility tests: conda deactivate; bash -i tests/backward_compatibility_tests.sh

[aylei]

/quicktest-core

[aylei]

/quicktest-core

[cg505]

I think this makes sense. @Michaelvll should also review.

[aylei]

Thanks for @Michaelvll 's idea, this PR is now greatly simplified and handles python -m sky.cli case correctly, ready for another look @cg505 @Michaelvll

[Michaelvll]

Ahh, this could be a bit dangerous, if a user specified a relative path for SKYPILOT_CONFIG=./config.yaml. Does this mean the config path will not be loaded locally?

[cg505]

We could use python -P CLI option, but this is only available in 3.11 and higher.

[aylei]

Great catch! Will investigate more