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 in 2 modes controlled by environment variables.
#
# With no special environment variables exported, the script will create a pants.pex from local
# sources if there is none at the root of the repo and then run that.
#
# If PANTS_DEV is exported then this script will instead run pants from the live sources in this
# repo.
#
# If PANTS_PROFILE=results.pstats is exported, then this script will run pants with python profiling
# enabled. It will create a pstats file named with the value of PANTS_PROFILE that you can analyze.
#
# Further support is added for projects wrapping pants with custom external extensions.  In the
# future this will work differently (see: https://github.com/pantsbuild/pants/issues/5), but
# currently pants extenders can invoke this script exporting a few environment variables to include
# the extension source and requirements for development purposes:
# WRAPPER_SRCPATH       This is a colon separated list of paths containing extension sourcecode.
# WRAPPER_REQUIREMENTS  This is a colon separated list of pip install compatible requirements.txt
#                       files.
#
# For example, with a wrapping project layed out like so:
# /src/wrapper/
#   src/main/python/
#     wrapper/
#       ...
#   dependencies/python/
#     BUILD
#     requirements.txt
#
# And a pantsbuild/pants clone like so:
# /src/pantsbuild-pants
#
# You could invoke pants in the wrapper with its custom extension enabled using a script like so:
# /src/wrapper/pants
# ==
# #!/usr/bin/env bash
# WRAPPER_REQUIREMENTS="/src/wrapper/dependencies/python/requirements.txt" \
# WRAPPER_SRCPATH=/src/wrapper/src/main/python \
#    exec /src/pantsbuild-pants/pants "$@"
#

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

source ${HERE}/build-support/pants_venv

PANTS_EXE="${HERE}/src/python/pants/bin/pants_exe.py"

if [ ! -z "${PANTS_PROFILE}" ]; then
  PANTS_EXE=" -m cProfile -o ${PANTS_PROFILE} ${PANTS_EXE}"

  # PEX_PROFILE requires a path that is directory-ish, otherwise it blows up with a strange error
  if [[ $PANTS_PROFILE != *"/"* ]]; then
    PANTS_PROFILE="./${PANTS_PROFILE}"
  fi
  export PEX_PROFILE=${PANTS_PROFILE}
fi

PANTS_BINARY=src/python/pants/bin:pants_local_binary
PANTS_PEX="${HERE}/pants.pex"
FAILED_BOOTSTRAP_SENTINEL="${HERE}/.pants.d/BOOTSTRAP_FAILED"

PY=${PY:-$(which python2.7)}

if [[ ! -z "${WRAPPER_REQUIREMENTS}" ]]; then
  PANTS_DEV=1
  REQUIREMENTS=(
    $(echo ${WRAPPER_REQUIREMENTS} | tr : ' ')
    ${REQUIREMENTS[@]}
  )
fi

PANTS_SRCPATH=(
  ${HERE}/src/python
)
if [[ ! -z "${WRAPPER_SRCPATH}" ]]; then
  PANTS_DEV=1
  PANTS_SRCPATH=(
    $(echo ${WRAPPER_SRCPATH} | tr : ' ')
    ${PANTS_SRCPATH[@]}
  )
fi
PANTS_SRCPATH="$(echo ${PANTS_SRCPATH[@]} | tr ' ' :)"

function run_pants_bare() {
  activate_pants_venv
  PYTHONPATH="${PANTS_SRCPATH}:${PYTHONPATH}" python ${PANTS_EXE} "$@"
}

function exec_pants_bare() {
  activate_pants_venv
  PYTHONPATH="${PANTS_SRCPATH}:${PYTHONPATH}" exec python ${PANTS_EXE} "$@"
}

if [ ! -z "${PANTS_DEV}" ]; then
  log "*** Running pants in dev mode from ${PANTS_EXE} ***"
  if [[ ! -z "${WRAPPER_REQUIREMENTS}" ]]; then
    log "***   with extra requirements: ${WRAPPER_REQUIREMENTS} ***"
  fi
  if [[ ! -z "${WRAPPER_SRCPATH}" ]]; then
    log "***   with extra sources ${WRAPPER_SRCPATH} ***"
  fi
  exec_pants_bare "$@"
else
  if [ ! -e "${PANTS_PEX}" ]; then
    if [ -f ${FAILED_BOOTSTRAP_SENTINEL} ] ; then
      log "Last bootstrap failed, cleaning up .pants.d"
      rm -rf ${HERE}/.pants.d
    fi
    log "Building pants.pex to ${PANTS_PEX}..."
    # TODO(John sirois): Re-plumb build such that it grabs constraints from the built python_binary
    # target(s).
    rm -rf ${PANTS_PEX} && \
    run_pants_bare binary ${PANTS_BINARY} && \
    mv -v ${HERE}/dist/pants_local_binary.pex ${PANTS_PEX} && \
    chmod +x ${PANTS_PEX}
    exit_status=$?
    if [ $exit_status != 0 ] ; then
      echo "*** Pants bootstrapping failed."
      echo "This file is left as a sentinel to record that bootstrapping pants failed." \
        > ${FAILED_BOOTSTRAP_SENTINEL}
      exit $exit_status
    fi
  fi
  if [ -e "${PANTS_PEX}" ]; then
    exec "${PANTS_PEX}" "$@"
  fi
fi