name: check-build-host
description: >-
  Report the build host and fail fast when executables, CPU or disk that the
  build needs are missing - a mistake should cost seconds, not hours.
inputs:
  tools:
    description: Space separated executables that must be on PATH
    required: false
    default: git python3
  min-disk-gb:
    description: Warn when the build filesystem has less than this much free
    required: false
    default: "100"
runs:
  using: composite
  steps:
    - name: Host report
      shell: bash
      run: |
        set -euo pipefail
        echo "os     : $(. /etc/os-release && echo "$PRETTY_NAME") ($(uname -m), $(uname -r))"
        echo "user   : $(id -un)  home=$HOME"
        echo "cpu    : $(nproc) cores / $(awk '/MemTotal/{printf "%.0fG", $2/1048576}' /proc/meminfo) ram"
        df -h . | tail -1 | sed 's/^/disk   : /'
        missing=""
        for tool in ${{ inputs.tools }}; do
          command -v "$tool" >/dev/null 2>&1 || missing="$missing $tool"
        done
        if [ -n "$missing" ]; then
          echo "::error::Host is missing:$missing"
          echo "Install them on the runner host, e.g. sudo apt-get install -y $missing"
          exit 1
        fi
        free_gb="$(df --output=avail -BG . | tail -1 | tr -d ' ')"
        if [ "$free_gb" -lt "${{ inputs.min-disk-gb }}" ]; then
          echo "::warning::only ${free_gb}G free on $(df --output=target . | tail -1); expected >= ${{ inputs.min-disk-gb }}G"
        fi