# `VLLM.ConfigHelper`
[🔗](https://github.com/nshkrdotcom/vllm/blob/v0.3.0/lib/vllm/config_helper.ex#L1)

Runtime configuration helper for using vLLM safely via SnakeBridge/Snakepit.

This module composes `SnakeBridge.ConfigHelper` and adds a vLLM-specific
safeguard around vLLM v1 multiprocessing (which can spawn child processes).

## v1 multiprocessing (vLLM 0.14+)

vLLM can spawn subprocesses for the engine core. Under Snakepit, those
subprocesses must be cleaned up deterministically on shutdown to avoid
orphaned GPU processes holding memory.

Configure with:

    config :vllm, v1_multiprocessing: :auto | :on | :off

- `:off` - always forces `VLLM_ENABLE_V1_MULTIPROCESSING=0`
- `:on` - forces `VLLM_ENABLE_V1_MULTIPROCESSING=1` and fails fast unless
  Snakepit process-group cleanup is available
- `:auto` - enables only when safe; otherwise forces off with a warning

When v1 multiprocessing is enabled, this helper also sets
`VLLM_WORKER_MULTIPROC_METHOD=spawn` (unless already provided) to avoid
forking a multi-threaded Python gRPC server.

# `v1_multiprocessing_mode`

```elixir
@type v1_multiprocessing_mode() :: :auto | :on | :off
```

# `configure_snakepit!`

```elixir
@spec configure_snakepit!(keyword()) :: :ok
```

Auto-configure Snakepit for SnakeBridge and enforce safe vLLM multiprocessing.

Intended for `config/runtime.exs`:

    import Config
    VLLM.ConfigHelper.configure_snakepit!()

Options:
- all options supported by `SnakeBridge.ConfigHelper.configure_snakepit!/1`
- `:v1_multiprocessing` - overrides `config :vllm, :v1_multiprocessing`

---

*Consult [api-reference.md](api-reference.md) for complete listing*