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mock_server

Mock streaming server — a frontend dev aid.

Boots the same FastAPI app the real streaming server uses, but backs it with :class:InProcessGpuPool wrapping a synthetic generator that emits pre-baked RGB frames. No GPU or model weights required.

Use cases:

  • Frontend development without a real model loaded.
  • Integration tests that exercise the WS protocol end-to-end.
  • Reproducing protocol bugs locally.

Launch: python -m fastvideo.entrypoints.streaming.mock_server.

Classes

fastvideo.entrypoints.streaming.mock_server.MockGenerator dataclass 

MockGenerator(sleep_ms: float = 0.0)

Generator stand-in that returns synthetic gradient frames.

Each call produces one segment worth of frames whose pixels vary by a constant derived from the request seed and segment index. Latency is configurable via sleep_ms so the caller can exercise slow- generate scenarios without spinning a GPU.

Functions

fastvideo.entrypoints.streaming.mock_server.build_mock_app 

build_mock_app(*, sleep_ms: float = 0.0)

Build a FastAPI app backed by :class:MockGenerator.

Source code in fastvideo/entrypoints/streaming/mock_server.py 
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def build_mock_app(*, sleep_ms: float = 0.0):
    """Build a FastAPI app backed by :class:`MockGenerator`."""
    serve_config = ServeConfig(
        generator=GeneratorConfig(model_path="/models/mock"),
        streaming=StreamingConfig(
            session_timeout_seconds=120,
            generation_segment_cap=6,
        ),
    )
    serve_config.default_request.sampling = SamplingConfig(
        num_frames=24,
        height=256,
        width=256,
        fps=24,
        num_inference_steps=1,
    )
    return build_app(serve_config, MockGenerator(sleep_ms=sleep_ms))