New package: py-luigi (#10970)

var/spack/repos/builtin/packages/py-luigi/package.py

+# Copyright 2013-2019 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack import *
+
+
+class PyLuigi(PythonPackage):
+    """Workflow mgmgt + task scheduling + dependency resolution"""
+
+    homepage = "https://github.com/spotify/luigi"
+    url      = "https://pypi.io/packages/source/l/luigi/luigi-2.8.3.tar.gz"
+
+    version('2.8.3', sha256='8b5c84a3c3f4df07309056d3b98348b93c054f1931b7ee22fc29e7989f645c9e')
+
+    depends_on('python@2.7:2.8,3.4:', type=('build', 'run'))
+    depends_on('py-setuptools', type='build')
+    depends_on('py-tornado@4.0:4.99', type=('build', 'run'))
+    depends_on('py-python-daemon@:2.1', type=('build', 'run'))
+    depends_on('py-dateutil@2.7.5', when='@2.8.3:', type=('build', 'run'))
+
+    depends_on('py-test@3.3.0:', type='test')