Setup python app in centos from scratch (centos 6.9+uwsgi+nginx+flask+mysql)

Initial setup

$ sudo yum update
$ sudo yum install epel-release
$ sudo yum groupinstall "Development tools"
$ sudo yum install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel telnet htop
$ sudo yum install python-devel python-virtualenv
$ sudo yum install mysql-connector-python mysql-devel mysql-server

Install Python

Download and install Python : https://www.python.org/

./configure && make && make altinstall

Install uWSGI

$ wget https://bootstrap.pypa.io/get-pip.py
$ which python2.7
$ sudo /usr/local/bin/python2.7 get-pip.py
$ which pip2.7
$ sudo /usr/local/bin/pip2.7 install uWSGI
$ which uwsgi
$ uwsgi --version

Setup vassels

$ sudo mkdir -p /etc/uwsgi/vassels

Setup Emperor service

$ sudo vim /etc/init.d/emperor
#!/bin/sh
# chkconfig: 2345 99 10
# Description: Starts and stops the emperor-uwsgi
# See how we were called.

RUNEMPEROR="/usr/local/bin/uwsgi --emperor=/etc/uwsgi/vassels"

PIDFILE=/var/run/emperor-uwsgi.pid
LOGFILE=/var/log/uwsgi/emperor.log

start() {
  if [ -f /var/run/$PIDNAME ] && kill -0 $(cat /var/run/$PIDNAME); then
    echo 'Service emperor-uwsgi already running' >&2
    return 1
  fi
  echo 'Starting Emperor...' >&2
  local CMD="$RUNEMPEROR &> \"$LOGFILE\" & echo $!"
  su -c "$CMD" > "$PIDFILE"
  echo 'Service started' >&2
}

stop() {
  if [ ! -f "$PIDFILE" ] || ! kill -0 $(cat "$PIDFILE"); then
    echo 'Service emperor-uwsgi not running' >&2
    return 1
  fi
  echo 'Stopping emperor-uwsgi' >&2
  kill -7 $(cat "$PIDFILE") && rm -f "$PIDFILE"
  echo 'Service stopped' >&2
}

status() {
    if [ ! -f "$PIDFILE" ]; then
	echo "Emperor is not running." >&2
	return 1
    else
    	echo "Emperor (pid  `cat ${PIDFILE}`) is running..."
    	ps -ef |grep `cat $PIDFILE`| grep -v grep
    fi
}

case "$1" in
start)
      start
      ;;
stop)
      stop
      ;;
status)
      status
      ;;
restart)
      stop
      start
      ;;
*)
    echo "Usage: emperor {start|stop|restart}"
    exit 1
esac

 Setup app user & environment

$ useradd foobar
$ usermod -md /srv/foobar foobar
$ chmod 755 /srv/foobar
$ sudo su - foobar
foobar@local~$ virtualenv --python=python2.7 ~/venv
foobar@local~$ mkdir www
foobar@local~$ mkdir logs
foobar@local~$ touch logs/uwsgi.log
foobar@local~$ touch uwsgi.ini
foobar@local~$ echo "source ~/venv/bin/activate" >> ~/.bashrc
foobar@local~$ source ~/venv/bin/activate
(venv)foobar@local~$ vim uwsgi.ini
[uwsgi]
master = true
processes = 2
socket = /tmp/foobar.sock

chdir = /srv/foobar/www
virtualenv = /srv/foobar/venv
module = app:app

uid = foobar
chown-socket = foobar:nginx
chmod-socket = 660
vacuum = true

die-on-term = true
python-autoreload = 3
py-autoreload = 1
logger = file:/srv/foobar/logs/uwsgi.log

Exit from foobar user & create uwsgi symlink

(venv)foobar@local~$ exit
$ sudo ln -s /srv/foobar/uwsgi.ini /etc/uwsgi/vassels/foobar.ini

Start emperor service & setup set the startup

$ sudo service emperor start
$ sudo chkconfig emperor on

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