Run Bazel daemon in a docker container

bazel_in_docker.sh

#!/usr/bin/env bash
set -o pipefail
set -o errexit
set -o nounset

CONTAINER_NAME="bazel-$USER"

# replace this with your own image where bazel is installed:
IMAGE="replace_this/bazel:0.11.1"

function log {
  echo "(wrapper) $*" 1>&2
}

function container_exists {
  docker ps -a --format '{{.Names}}' | grep -qE "^$CONTAINER_NAME\$"
}

function container_running {
  docker ps --format '{{.Names}}' | grep -qE "^$CONTAINER_NAME\$"
}

function create_container {
  log "Creating a new container"

  tmpf=$(mktemp)
  trap 'rm -f "$tmpf"' ERR EXIT
  cat > "$tmpf" <<'EOF'
#!/bin/sh
stty sane
cd "$1"
shift
"$@"
EOF
  chmod 0755 "$tmpf"

  docker create \
    --network host \
    --interactive \
    -v "$HOME:$HOME" \
    -v "/run/user/$UID/gnupg:/run/user/$UID/gnupg" \
    -v "/var/tmp/_bazel_$USER:/var/tmp/_bazel_$USER" \
    -v "/var/run/docker.sock:/var/run/docker.sock" \
    --name "$CONTAINER_NAME" \
    -w "$HOME" \
    "$IMAGE"
  docker cp "$tmpf" "$CONTAINER_NAME:/usr/local/bin/run_in_dir.sh"
  rm -f "$tmpf"

  start_container

  USER=${USER:-$(whoami)}
  log "Adding user account: $USER"
  docker exec "$CONTAINER_NAME" \
    groupadd -f -g 131 -r docker
  docker exec "$CONTAINER_NAME" \
    useradd --home-dir "$HOME" \
            --uid "$UID" \
            --gid "${GROUPS[0]}" \
            --no-create-home \
            --no-user-group \
            --shell /bin/bash \
            --groups docker \
            "$USER"
}

function start_container {
  log "Starting container"
  docker start "$CONTAINER_NAME"
}

function main {
  if ! container_exists; then
    create_container
  elif ! container_running; then
    start_container
  fi

  docker exec \
    --env SSH_AUTH_SOCK="$SSH_AUTH_SOCK" \
    --user "$UID" \
    --tty \
    --interactive \
    "$CONTAINER_NAME" \
    /usr/local/bin/run_in_dir.sh "$PWD" bazel "$@"
}

main "$@"