#!/bin/sh
# Build and push one service's image, inside limits Tower can afford.
#
#   sh scripts/build-image.sh ipx|directory|play|web|coverage
#
# On 2026-11-04 a plain `docker buildx build` of ipx (its dependencies' cache layer invalidated
# by a Cargo.toml change) rebuilt everything in release on all twelve threads with 5 GB free and
# no swap; Tower thrashed for three hours with every core pegged and had to be rebooted. So the
# build runs in a BuildKit container under a cgroup cap: past the memory cap the build is killed,
# it does not take production down with it. And it does not start without room for that cap.
set -eu

MEM=6g           # the builder's memory cap (Tower has no swap to spill into)
CPUS=0-5         # six of twelve threads; cargo inside sees six and runs six jobs
NEED_KB=$((9 * 1024 * 1024))  # the cap plus 3 GB for everything else
MAX_LOAD=12
BUILDER=ipx-capped

case "${1:-}" in
  ipx)       FILE=Dockerfile;           IMAGE=ipx ;;
  directory) FILE=Dockerfile.directory; IMAGE=ipx-directory ;;
  play)      FILE=Dockerfile.play;      IMAGE=ipx-play ;;
  web)       FILE=Dockerfile.web;       IMAGE=ipx-web ;;
  # Not a service: what scripts/coverage.sh runs the Rust tests in (#390).
  coverage)  FILE=Dockerfile.coverage;  IMAGE=ipx-coverage ;;
  *) echo "usage: $0 ipx|directory|play|web|coverage" >&2; exit 2 ;;
esac
cd "$(dirname "$0")/.."

avail=$(awk '/^MemAvailable:/ {print $2}' /proc/meminfo)
load=$(cut -d' ' -f1 /proc/loadavg)
echo "MemAvailable $((avail / 1024)) MB, load $load"
if [ "$avail" -lt "$NEED_KB" ]; then
  echo "refusing: under $((NEED_KB / 1024 / 1024)) GB available. Wait, or find what is using it." >&2
  exit 1
fi
if awk -v l="$load" -v m="$MAX_LOAD" 'BEGIN { exit !(l > m) }'; then
  echo "refusing: load over $MAX_LOAD. Wait for it to come down." >&2
  exit 1
fi

# Made once; buildx starts its container again when needed, after a reboot too.
if ! docker buildx inspect "$BUILDER" >/dev/null 2>&1; then
  docker buildx create --name "$BUILDER" --driver docker-container \
    --driver-opt "memory=$MEM,cpuset-cpus=$CPUS" \
    --buildkitd-config scripts/buildkitd.toml >/dev/null
fi

exec docker buildx build --builder "$BUILDER" -f "$FILE" \
  --tag "192.168.1.130:5000/$IMAGE:latest" --push .