PythonPipRecipe

# PythonPipRecipe — recipe for pure-Python packages installed from PyPI
#
# Installs the package by running:
#   python -m pip install <PYPI_NAME>==<PKGVERSION>
#
# No source tarball is required; omit the `sources:` field in the recipe header.
# The package name passed to pip is derived from PKGNAME (set by bits from the
# `package:` field).  pip normalises underscores and hyphens, so both forms work.
#
# When the PyPI package name differs from the bits package name, set PYPI_NAME
# in the recipe before or after the bits-include line, e.g.:
#   PYPI_NAME="python-prctl"
#   . $(bits-include PythonPipRecipe)
# PYPI_NAME overrides the default (PKGNAME) only for the pip install call;
# all other bits machinery continues to use PKGNAME.
#
# Requirement: Python must be in the recipe's `requires:` list so that
# Python_ROOT is set in the environment before this file is sourced.

. ${BITS_RECIPE_TOOLS_ROOT}/PythonRecipe

# No source tarball: skip the rsync Prepare step
function Prepare() { true; }

function MakeInstall() {
  mkdir -p "${SITE_PACKAGES}"
  # PYPI_NAME may be set by the recipe to override the PyPI package name when
  # it differs from the bits package name (e.g. PYPI_NAME="python-prctl").
  local _pip_name="${PYPI_NAME:-${PKGNAME}}"
  # --no-deps          deps are managed by bits, not pip
  # --ignore-installed don't try to uninstall system packages before installing;
  #                    avoids "Permission denied" when a system copy exists
  # --root=/ --prefix= install directly into our package tree; no staging dir
  "${PYTHON_EXE}" -m pip install \
    --no-deps --ignore-installed \
    --root=/ --prefix="${INSTALLROOT}" \
    "${_pip_name}==${PKGVERSION}"
  # Verify pip actually installed something — catches silent failures where pip
  # exits 0 but the package was not found or the index was unreachable.
  if [ -z "$(ls -A "${SITE_PACKAGES}" 2>/dev/null)" ]; then
    echo "PythonPipRecipe: pip exited 0 but ${SITE_PACKAGES} is empty" >&2
    echo "PythonPipRecipe: check that ${_pip_name}==${PKGVERSION} exists on the configured index" >&2
    return 1
  fi
}