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 "" 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

Setup uWSGI and Emperor on Centos 6.xx

uWSGI is driving me crazy when install it, every single time. I’m using Centos 6.9 to setup my python app.

This one is for setup uWSGI and make sure you already installed Python2.7 on your machine:

$ 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

Test your app with uWSGI manually:

$ sudo /usr/local/bin/uwsgi --ini /dir/to/app/uwsgi.ini

Setup vassels from uwsgi ini file

$ sudo mkdir -p /etc/uwsgi/vassels
$ sudo ln -s /dir/to/app/uwsgi.ini /etc/uwsgi/vassels/appname.ini

Create emperor to make uWSGI as a 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 "" in
start)
      start
      ;;
stop)
      stop
      ;;
status)
      status
      ;;
restart)
      stop
      start
      ;;
*)
    echo "Usage: emperor {start|stop|restart}"
    exit 1
esac
$ sudo chmod +x /etc/init.d/emperor
$ sudo /etc/init.d/emperor start
$ sudo chkconfig emperor on

Check your app if it’s already running:

$ sudo ps -ef | grep uwsgi