circleci-config.yml

# Carbon-Aware CI for CircleCI
#
# Add this to your .circleci/config.yml or use as an orb.
# Set environment variables in CircleCI Project Settings:
#   GRID_ZONE: Grid zone to check (default: auto:detect)
#   MAX_CARBON: Max gCO2eq/kWh threshold (default: 250)
#   ELECTRICITY_MAPS_TOKEN: Optional, for global coverage
#   ENTSOE_TOKEN: Optional, for EU coverage
#
# Usage: Add the carbon-check job before your heavy build jobs.
# The build job only runs if the grid is clean.

version: 2.1

jobs:
  carbon-check:
    docker:
      - image: cimg/python:3.11
    steps:
      - checkout
      - run:
          name: Install dependencies
          command: pip install -q uv && uv pip install --system -q requests==2.32.*
      - run:
          name: Check grid carbon intensity
          command: |
            python -c "
            import os, sys
            sys.path.insert(0, '.')
            from check_grid import parse_zones_input, check_carbon_intensity
            from providers import detect_provider

            zone_str = os.environ.get('GRID_ZONE', 'auto:detect')
            max_carbon = float(os.environ.get('MAX_CARBON', '250'))
            entsoe_token = os.environ.get('ENTSOE_TOKEN', '')

            zones = parse_zones_input(zone_str)
            zone = zones[0]['zone'] if zones else 'CISO'
            provider = detect_provider(zone, entsoe_token)
            is_green, intensity = check_carbon_intensity(
                zone, max_carbon, provider,
                eia_api_key=os.environ.get('EIA_API_KEY', ''),
                emaps_api_key=os.environ.get('ELECTRICITY_MAPS_TOKEN', ''),
                entsoe_token=entsoe_token,
            )
            result = 'true' if is_green else 'false'
            # Write to file for downstream jobs
            with open('/tmp/carbon_result.txt', 'w') as f:
                f.write(result)
            with open('/tmp/carbon_intensity.txt', 'w') as f:
                f.write(str(intensity or 'unknown'))
            print(f'Grid clean: {result} ({intensity} gCO2eq/kWh)')
            "
      - persist_to_workspace:
          root: /tmp
          paths:
            - carbon_result.txt
            - carbon_intensity.txt

  build:
    docker:
      - image: cimg/base:current
    steps:
      - attach_workspace:
          at: /tmp
      - run:
          name: Check carbon result
          command: |
            GRID_CLEAN=$(cat /tmp/carbon_result.txt)
            if [ "$GRID_CLEAN" != "true" ]; then
              echo "Grid is dirty ($(cat /tmp/carbon_intensity.txt) gCO2eq/kWh). Skipping build."
              circleci-agent step halt
            fi
            echo "Grid is clean! Running build on green energy..."
      - checkout
      - run:
          name: Build
          command: |
            echo "Your build commands here"

workflows:
  carbon-aware-build:
    # Schedule: run hourly (CircleCI scheduled triggers)
    # Configure in CircleCI UI: Project Settings → Triggers
    jobs:
      - carbon-check
      - build:
          requires:
            - carbon-check