response_header sounds like a check that the endpoint is alive, and for a
streaming request it is: headers arrive before generation starts. For a
non-streaming request the engine sends nothing until the completion is
finished, so the same setting is the total generation budget wearing a
liveness timeout's name.
At 60s that was invisible on GPUs and a hard cap of roughly a hundred
tokens on qwen2.5-coder-14b at 1.7 tokens a second. A request for 120
tokens failed at exactly one minute, and neither the setting's name nor the
error said why.
Two transports now: the short header timeout for streaming, where it still
catches a sick endpoint, and a generation budget for non-streaming,
defaulting to ten minutes. One number could not mean both things.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
llmgw server is real now. It fronts a static set of engine replicas with an
OpenAI-compatible API, scoring endpoints through the pipeline added in the
previous commit.
- proxy: SSE relayed event by event with a flush after each, cancellation
propagated upstream, and separate deadlines for dial, headers, first token,
inter-token idle and total. The idle watchdog is what distinguishes a wedged
engine from a slow one.
- router: dispatch with retry and model fallback. Retry only happens while
nothing has reached the client; after that, splicing two responses together
would be worse than the short stream the client already sees.
- config: YAML via koanf overlaid on defaults, with LLMGW_ env overrides.
Validation rejects duplicate endpoint ids and aliases that shadow a model,
because both misroute silently at request time rather than failing loudly.
- metrics: requests, duration, TTFT, tokens, plus per-scorer values and
per-filter drops on a separate admin listener with health and pprof.
Phase 1 exit criterion, measured in test/e2e: 1000 concurrent streams across
3 sim-engines complete at ~6800 req/s; every client disconnect frees the KV
blocks on every engine; router overhead p99 is about 0.9 ms against the plan's
2 ms budget.
The handlers live in internal/router rather than an internal/router/openai
package as the plan's tree sketched: they need the dispatch loop, and splitting
them apart would have meant an interface with exactly one implementation. Plan
§4 updated to match.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>