perf(cloud): shrink fal cold start by ~20s#1024
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Three changes that target the cold-start path measured in fal.log: - livepeer_fal_app.py: drop `requirements = [...]` so fal isolate stops provisioning a separate venv on top of the image's. The image already has websockets/httpx/aiokafka via the kafka extra below. - Dockerfile.cloud: pre-build the venv with `uv sync --extra livepeer --extra kafka --no-dev` so the runtime `uv run --extra livepeer --extra kafka livepeer-runner` is a no-op instead of fetching + installing aiokafka, uvloop, and re-resolving ~50 packages. - livepeer_fal_app.py dockerfile_str: re-sync after `COPY src/` so the daydream-scope editable install is refreshed at image build time, eliminating the "Built daydream-scope @ file:///app" rebuild on every cold start. - livepeer_app.py lifespan: pre-warm the pipeline registry so the torch/diffusers/transformers/torchao import cascade runs at runner startup instead of on the first cloud-proxy call (~8s shifted off the user-perceived connect path). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> Signed-off-by: emranemran <emran.mah@gmail.com>
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Empty `requirements` broke the wrapper at first websocket — fal isolate runs the App's setup() / websocket handler in a venv separate from the image's /app/.venv (under /usr/local/lib/python3.12/dist-packages), where httpx wasn't available, so check_runner_readiness raised ModuleNotFoundError on every connect. The ~10s cold-start tax that motivated emptying requirements was actually `uv run --extra livepeer --extra kafka` resyncing the image venv, not isolate. The Dockerfile.cloud `uv sync --extra livepeer --extra kafka --no-dev` and the fal-side dockerfile_str re-sync from the previous commit already address that on their own. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> Signed-off-by: emranemran <emran.mah@gmail.com>
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Summary
Three changes to the fal cold-start path, derived from a real cold-start trace in
fal.log:livepeer_fal_app.py: droprequirements = [...]so fal isolate stops provisioning a separate venv on top of the image's. Combined with the Dockerfile change below, removes the ~10–12sDownloaded transformers / Uninstalled 50 packages / Installed 56 packagesblock visible on every cold start.Dockerfile.cloud: pre-build the venv withuv sync --extra livepeer --extra kafka --no-devso the runtimeuv run --extra livepeer --extra kafka livepeer-runneris a no-op.livepeer_fal_app.pydockerfile_str: re-sync afterCOPY src/so thedaydream-scopeeditable install is refreshed at image build time (kills theBuilt daydream-scope @ file:///apprebuild on every cold start).livepeer_app.pylifespan: pre-warm the pipeline registry so the torch/diffusers/transformers/torchao import cascade runs at runner startup instead of on the first cloud-proxy call (~8s shifted off the user-perceived connect path).Combined expected savings: ~20s of user-visible cold start.
Test plan
uv run ruff check src/scope/cloud/livepeer_app.py src/scope/cloud/livepeer_fal_app.py— cleanuv run ruff format --check— already formattedpy_compile)falSDK loadslivepeer_fal_app.pyand reportsrequirements = []scope-livepeer-emran, force a cold start, capture runner logs, compare phase deltas vs the baselinefal.log. The "Downloaded / Uninstalled / Installed" block should be gone, andRegistry initializedshould fire before the first WS handshake.🤖 Generated with Claude Code