The build_commands feature allows you to run custom Docker commands during the build stage, enabling advanced caching, dependency management, and environment setup. Use Cases:
  • Clone GitHub repositories
  • Install dependencies
  • Create directories
  • Pre-download model weights

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1. Using Build Commands in config.yaml

Add build_commands to your config.yaml: 
build_commands:
  - git clone https://github.com/comfyanonymous/ComfyUI.git
  - cd ComfyUI && git checkout b1fd26fe9e55163f780bf9e5f56bf9bf5f035c93 && pip install -r requirements.txt
model_name: Build Commands Demo
python_version: py310
resources:
  accelerator: A100
  use_gpu: true
What happens?
  • The GitHub repository is cloned.
  • The specified commit is checked out.
  • Dependencies are installed.
  • Everything is cached at build time, reducing deployment cold starts.

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2. Creating Directories in Your Truss

Use build_commands to create directories directly in the container. 
build_commands:
  - git clone https://github.com/comfyanonymous/ComfyUI.git
  - cd ComfyUI && mkdir ipadapter
  - cd ComfyUI && mkdir instantid
Useful for large codebases requiring additional structure.

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3. Caching Model Weights Efficiently

For large weights (10GB+), use model_cache or external_data.
For smaller weights, use wget in build_commands: 
build_commands:
  - git clone https://github.com/comfyanonymous/ComfyUI.git
  - cd ComfyUI && pip install -r requirements.txt
  - cd ComfyUI/models/controlnet && wget -O control-lora-canny-rank256.safetensors https://huggingface.co/stabilityai/control-lora/resolve/main/control-LoRAs-rank256/control-lora-canny-rank256.safetensors
  - cd ComfyUI/models/controlnet && wget -O control-lora-depth-rank256.safetensors https://huggingface.co/stabilityai/control-lora/resolve/main/control-LoRAs-rank256/control-lora-depth-rank256.safetensors
model_name: Build Commands Demo
python_version: py310
resources:
  accelerator: A100
  use_gpu: true
system_packages:
  - wget
Why use this?
  • Reduces startup time by preloading model weights during the build stage.
  • Ensures availability without runtime downloads.

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4. Running Any Shell Command

The build_commands feature lets you execute any shell command as if running it locally, with the benefit of caching the results at build time. Key Benefits:
  • Reduces cold starts by caching dependencies & data.
  • Ensures reproducibility across deployments.
  • Optimizes environment setup for fast execution.