# What does this PR do?
As shown in #3421, we can scale stack to handle more RPS with k8s
replicas. This PR enables multi process stack with uvicorn --workers so
that we can achieve the same scaling without being in k8s.
To achieve that we refactor main to split out the app construction
logic. This method needs to be non-async. We created a new `Stack` class
to house impls and have a `start()` method to be called in lifespan to
start background tasks instead of starting them in the old
`construct_stack`. This way we avoid having to manage an event loop
manually.
## Test Plan
CI
> uv run --with llama-stack python -m llama_stack.core.server.server
benchmarking/k8s-benchmark/stack_run_config.yaml
works.
> LLAMA_STACK_CONFIG=benchmarking/k8s-benchmark/stack_run_config.yaml uv
run uvicorn llama_stack.core.server.server:create_app --port 8321
--workers 4
works.
# What does this PR do?
<!-- Provide a short summary of what this PR does and why. Link to
relevant issues if applicable. -->
This PR removes `init()` from `LlamaStackAsLibrary`
Currently client.initialize() had to be invoked by user.
To improve dev experience and to avoid runtime errors, this PR init
LlamaStackAsLibrary implicitly upon using the client.
It prevents also multiple init of the same client, while maintaining
backward ccompatibility.
This PR does the following
- Automatic Initialization: Constructor calls initialize_impl()
automatically.
- Client is fully initialized after __init__ completes.
- Prevents consecutive initialization after the client has been
successfully initialized.
- initialize() method still exists but is now a no-op.
<!-- If resolving an issue, uncomment and update the line below -->
<!-- Closes #[issue-number] -->
fixes https://github.com/meta-llama/llama-stack/issues/2946
---------
Signed-off-by: Mustafa Elbehery <melbeher@redhat.com>
# What does this PR do?
- Initialize route_impls to None in constructor to prevent
AttributeError
- Consolidate initialization checks to single point in request() method
- Improve error message to be more helpful ("Please call initialize()
first")
- Add comprehensive test suite to prevent regressions
The library client now has better error handling when users forget to
call initialize(), showing a clear ValueError instead of confusing
AttributeError. All initialization validation is now centralized in the
request() method, with internal methods (_call_non_streaming,
_call_streaming, _convert_body) relying on this single check for
cleaner, more maintainable code.
closes#2943
## Test Plan
`./scripts/unit-tests.sh`
