#!/bin/bash
# one-line change = a value never built before, so the cache can't already hold it
cd "$(dirname "$0")"
for d in cache-bad cache-good; do
  echo "print('base')" > $d/main.py
  docker build -q -t ctr-$d $d >/dev/null
  echo "print('$(date +%s)-$RANDOM')" > $d/main.py
  s=$(python3 -c 'import time;print(time.time())')
  docker build --progress=plain -t ctr-$d $d > $d.log 2>&1
  e=$(python3 -c 'import time;print(time.time())')
  grep -E '^#[0-9]+ (\[[0-9]/[0-9]\]|CACHED|DONE)' $d.log | grep -v 'load\|metadata' | sed 's/^/   /'
  printf '%s rebuild after one-line change: %.1fs\n' $d "$(python3 -c "print($e-$s)")"
done