pants

#!/usr/bin/env bash
# Copyright 2014 Pants project contributors (see CONTRIBUTORS.md).
# Licensed under the Apache License, Version 2.0 (see LICENSE).

# This bootstrap script runs pants from the live sources in this repo.
#
# The script defaults to running with either Python 3.7 or Python 3.8. To use another Python version,
# prefix the script with `PY=python3.8`.

set -eo pipefail

HERE=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)

# Source any custom bootstrap settings for Pants from PANTS_BOOTSTRAP if it exists.
: "${PANTS_BOOTSTRAP:=.pants.bootstrap}"
if [[ -f "${PANTS_BOOTSTRAP}" ]]; then
  # shellcheck source=/dev/null
  source "${PANTS_BOOTSTRAP}"
fi

# Exposes:
# + determine_python: Determine which interpreter version to use.
# shellcheck source=build-support/common.sh
source "${HERE}/build-support/common.sh"

PY="$(determine_python)"
export PY

# Exposes:
# + activate_pants_venv: Activate a virtualenv for pants requirements, creating it if needed.
# shellcheck source=build-support/pants_venv
source "${HERE}/build-support/pants_venv"

# Exposes:
# + bootstrap_native_code: Builds target-specific native engine binaries.
# shellcheck source=build-support/bin/rust/bootstrap_code.sh
source "${HERE}/build-support/bin/rust/bootstrap_code.sh"

function exec_pants_bare() {
  PANTS_PY_EXE="${HERE}/src/python/pants/bin/pants_loader.py"
  PANTS_SRCPATH="${HERE}/src/python"

  # Redirect activation and native bootstrap to ensure that they don't interfere with stdout.
  activate_pants_venv 1>&2
  bootstrap_native_code 1>&2

  if [ -n "${PANTS_DEBUG}" ]; then
    if [[ "$*" != *"--no-pantsd"* ]]; then
      echo "Error! Must pass '--no-pantsd' when using PANTS_DEBUG"
      exit 1
    fi
    DEBUG_ARGS="-m debugpy --listen 127.0.0.1:5678 --wait-for-client"
    echo "Will launch debugpy server at '127.0.0.1:5678' waiting for client connection."
  fi

  if [ -z "${PANTS_NO_NATIVE_CLIENT}" ]; then
    set +e
    "${NATIVE_CLIENT_BINARY}" "$@"
    result=$?
    # N.B.: The native pants client currently relies on pantsd being up. If it's not, it will fail
    # with exit code 75 (EX_TEMPFAIL in /usr/include/sysexits.h) and we should fall through to the
    # python pants client which knows how to start up pantsd. This failure takes O(1ms); so has no
    # appreciable impact on --no-pantsd runs.
    #
    # TODO: Split out a `pants_server` or `pants_legacy_entrypoint` from this script, and then use
    # the native client's support for fallback to the legacy entrypoint to remove the special
    # exit code case.
    if ((result != 75)); then
      exit ${result}
    fi
    set -e
  fi

  # shellcheck disable=SC2086
  PYTHONPATH="${PANTS_SRCPATH}:${PYTHONPATH}" RUNNING_PANTS_FROM_SOURCES=1 NO_SCIE_WARNING=1 \
    exec ${PANTS_PREPEND_ARGS:-} "$(venv_dir)/bin/python" ${DEBUG_ARGS} "${PANTS_PY_EXE}" "$@"
}

exec_pants_bare "$@"