please

#!/bin/sh

set -eu

# DEBUG
#set -x

silent() {
  out=$("$@" 2>&1) || { echo "$out"; exit 1; }
}
RED='\033[0;31m'
GREEN='\033[0;32m'
NC='\033[0m'


USE_DOCKER=1
USE_NIX=${USE_NIX:-0}
if [ -f /.dockerenv ]; then
  USE_NIX=1
  . /etc/nix/profile.sh;
fi

# Detect OSX
SHASUM="sha256sum"
NETWORK_OPTIONS="--network=host"
if uname -a | grep -q Darwin; then
    SHASUM="shasum -a 256"
    # Binding to 127.0.0.1 doesn't work on macosx
    # --network="host" is not supported on macosx
    # Try to minimise the forwarded ports to avoid open file limits.
    NETWORK_OPTIONS="-e HOST=0.0.0.0 -p 8000-8040:8000-8040 -p 9000:9000 -p 7000:7000 -p 6379:6379"
fi

if [ "$USE_NIX" = "1" ]; then
  drv=$(nix-instantiate nix/default.nix -A please-cli) 2> /dev/null
  nix_store_file=$(cut -c17-91 < "$drv")
  building_please_cli=0
  if [ ! -e "$nix_store_file" ]; then
    building_please_cli=1
    printf " => Building please command (this might take a minute or two the first time) ... ";
  fi

  silent nix-build nix/default.nix -A please-cli -o result-please-cli;
  if [ "$building_please_cli" = "1" ]; then
    echo "${GREEN}DONE${NC}";
  fi
  exec ./result-please-cli/bin/please "$@";

else
  if [ "$USE_DOCKER" = "1" ]; then
    DOCKER_HASH="$(pwd)$(git rev-parse --abbrev-ref HEAD)"
    DOCKER_NAME="mozilla-releng-services-v$(cat ./VERSION)-$(printf "%s" "$DOCKER_HASH" | $SHASUM | cut -d ' ' -f 1)"
    if [ ! "$(docker ps -q -f name="$DOCKER_NAME")" ]; then
      if [ ! "$(docker ps -qa -f name="$DOCKER_NAME")" ]; then
        docker run \
            --privileged \
            -td \
            --name "$DOCKER_NAME" \
            --volume="$(pwd)":/app \
            --volume=/var/run/docker.sock:/var/run/docker.sock \
            --workdir=/app \
            $NETWORK_OPTIONS \
            "mozillareleng/services:base-$(cat ./VERSION)"
      else
        docker start "$DOCKER_NAME"
      fi
   fi
   docker exec --tty --interactive --privileged "$DOCKER_NAME" ./please "$@"
   # TODO: stop old docker instances
  else
    # TODO: better error message and point to documentation
    echo "${RED}ERROR: please install nix or docker!${NC}"
  fi
fi