[serve] Fix bug with 'proxy_location' set for 'serve run' CLI command + discrepancy fix in Python API 'serve.start' function

[axreldable]

Why are these changes needed?

1. Fix bug with 'proxy_location' set for 'serve run' CLI command

serve run CLI command ignores proxy_location from config and uses default value EveryNode.

Steps to reproduce:

• have a script:

# hello_world.py
from ray.serve import deployment

@deployment
async def hello_world():
    return "Hello, world!"

hello_world_app = hello_world.bind()

Execute:

ray stop
ray start --head
serve build -o config.yaml hello_world:hello_world_app

• change proxy_location in the config.yaml: EveryNode -> Disabled

serve run config.yaml
curl -s -X GET "http://localhost:8265/api/serve/applications/" | jq -r '.proxy_location'

Output:

Before change:
EveryNode - but Disabled expected
After change:
Disabled

2. Fix discrepancy for 'proxy_location' in the Python API 'start' method

serve.start function in Python API sets different http_options.location depending on if http_options is provided.

Steps to reproduce:

• have a script:

# discrepancy.py
import time

from ray import serve
from ray.serve.context import _get_global_client

if __name__ == '__main__':
    serve.start()
    client = _get_global_client()
    print(f"Empty http_options: `{client.http_config.location}`")

    serve.shutdown()
    time.sleep(5)

    serve.start(http_options={"host": "0.0.0.0"})
    client = _get_global_client()
    print(f"Non empty http_options: `{client.http_config.location}`")

Execute:

ray stop
ray start --head
python -m discrepancy

Output:

Before change:
Empty http_options: `EveryNode`
Non empty http_options: `HeadOnly`
After change:
Empty http_options: `EveryNode`
Non empty http_options: `EveryNode`

---

It changes current behavior in the following ways:

1. serve run CLI command respects proxy_location parameter from config instead of using the hardcoded EveryNode.
2. serve.start function in Python API stops using the default HeadOnly in case of empty proxy_location and provided http_options dictionary without location specified.

Related issue number

Aims to simplify changes in the PR: #56507

Checks

• I've signed off every commit(by using the -s flag, i.e., git commit -s) in this PR.
• I've run pre-commit jobs to lint the changes in this PR. (pre-commit setup)
• I've included any doc changes needed for https://docs.ray.io/en/master/.
  • I've added any new APIs to the API Reference. For example, if I added a
    method in Tune, I've added it in doc/source/tune/api/ under the
    corresponding .rst file.
• I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
• Testing Strategy
  • Unit tests
  • Release tests
  • This PR is not tested :(

[axreldable]

This is the current value which is used implicitly.

[cursor]

Bug: Proxy Location Conversion Error

The _prepare_http_options function is missing the string-to-ProxyLocation enum conversion for proxy_location. This logic was present in the original start() function but removed, causing runtime errors when proxy_location is passed as a string to ProxyLocation._to_deployment_mode.

 

[axreldable]

This transformation was redundant.