component-setup-teardown

Demonstrates component setup and teardown lifecycle hooks — automatic dependency installation and per-run cleanup.

Structure

component-setup-teardown/
├── workflow.yaml
├── components/
│   └── word-counter/
│       └── component.yaml    # setup + teardown hooks
└── resources/
    ├── 01-count-intro.yaml
    ├── 02-count-poem.yaml
    └── 03-response.yaml

Usage

kdeps run examples/component-setup-teardown

What Happens on First Run

kdeps reads the setup block and automatically installs dependencies:

[setup] word-counter v1.0.0
  • pip install nltk             ← pythonPackages
  • apt-get install -y wc        ← osPackages (skipped if already present)
  • python3 -c "import nltk; nltk.download('punkt', quiet=True)"  ← commands
[setup] complete — cached for this version

On subsequent runs the setup cache is hit and setup is skipped entirely.

Setup Block

setup:
  pythonPackages:
    - nltk                        # installed via uv pip into isolated venv
  osPackages:
    - wc                          # installed via apt-get / apk / brew
  commands:
    - "python3 -c \"import nltk; nltk.download('punkt', quiet=True)\""

• pythonPackages — pip packages installed into the kdeps-managed Python venv
• osPackages — system packages; installer is auto-detected (apt-get / apk / brew); already-installed packages are skipped
• commands — shell commands run once after packages are ready

Teardown Block

teardown:
  commands:
    - "rm -f /tmp/word-counter-*.tmp"

Teardown runs after every invocation, not just the first. Use it for:

• Deleting temporary files
• Releasing locks
• Resetting per-run state

Setup vs Teardown Timing

Hook	When it runs
setup	Once per component version (cached)
teardown	After every component invocation

Sample Output

{
  "intro_stats": "{\"label\":\"intro\",\"word_count\":18,\"sentence_count\":2,\"unique_words\":18,\"avg_word_len\":4.28}",
  "poem_stats":  "{\"label\":\"poem\",\"word_count\":22,\"sentence_count\":3,\"unique_words\":19,\"avg_word_len\":3.86}"
}

Validate

kdeps validate examples/component-setup-teardown