cfe-lab/Kive: Python 3

The main change is #721 updating to Python 3. Other changes include:

• #785, #786, and #782 improve error handling when launching Slurm jobs.
• #774 and #793 fix permissions bugs.
• #833 removes PostgreSQL 9 left by the previous release.

See the milestone for a complete list.

• Install Python 3.6 and switch Apache to launch it.

  sudo systemctl stop httpd
  sudo yum install centos-release-scl
  sudo yum install python36 python36-devel rh-python36-mod_wsgi
  sudo cp /opt/rh/httpd24/root/usr/lib64/httpd/modules/mod_rh-python36-wsgi.so /lib64/httpd/modules
  sudo cp /opt/rh/httpd24/root/etc/httpd/conf.modules.d/10-rh-python36-wsgi.conf /etc/httpd/conf.modules.d
  sudo mv /opt/venv_kive /opt/py27_venv_kive
  sudo python3.6 -m venv /opt/venv_kive
  sudo /opt/venv_kive/bin/python -m pip install --upgrade pip
  sudo /opt/venv_kive/bin/python -m pip install -r requirements.txt
  sudo sed -ie 's/python2.7/python3.6/' /etc/httpd/conf.d/001-kive.conf
  sudo systemctl start httpd
  

• Add KIVE_SLURM_PATH entry to /etc/sysconfig/httpd.

• Remove Python 2's .pyc files with find . -name '*.pyc' -delete.
• Remove PostgreSQL 9 with sudo yum remove postgresql-libs. That will take the other packages that depend on it.
• The Python packages in Kive's virtual environment should already be up to date, because you just installed them. That should include the switch to psycopg2-binary.