Environment construction of Flask / MySql / Apache / mod_wsgi / virtualenv with Redhat7 (Python2.7) November 2020

Verification environment

• Red Hat Enterprise Linux Server release 7.9 (Maipo)
• Python 2.7.5
• Apache/2.4.6 (Red Hat Enterprise Linux)
• Flask 1.1.2
• MySql mysql Ver 8.0.22 for Linux on x86_64 (MySQL Community Server - GPL)
• pip 20.2.4
• virtualenv 20.1.0

Installation and creation of application files

Install Apache / mod_wsgi

$ sudo su
$ yum install httpd
$ chkconfig httpd on
$ service httpd start
$ service httpd status #Confirmation
$ yum install mod_wsgi # mod_wsgi installation

pip installation

$ curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
$ python get-pip.py

Install virtualenv

$ pip install virtualenv

Create application directory

$ mkdir /var/www/myapp
$ cd /var/www/myapp
$ virtualenv venv #Building a virtualenv environment
$ source venv/bin/activate #virtualenv enabled
$ pip install flask #installing flask
$ touch app.py #Create application file
$ touch app.wsgi #Create application file

app.py

from flask import Flask, jsonify

app = Flask(__name__)

@app.route("/")
def hello():
    return jsonify("Hello World!"), 201


if __name__ == "__main__":
    app.run()

app.wsgi

import os
import sys

DIR=os.path.dirname(__file__)
sys.path.append(DIR)
activate_this = os.path.join(DIR, 'venv/bin/activate_this.py')
execfile(activate_this, dict(__file__=activate_this))

from app import app as application

The final file structure is as follows.

$ tree -L 2
.
├── app.py
├── app.wsgi
└── venv
    ├── bin
    ├── lib
    ├── lib64
    └── pyvenv.cfg

Apache / mod_wsgi settings

$ vi /etc/httpd/conf/httpd.conf

Add the following line

Listen 8888

When I add port 8888 and restart apache, I get the following error

(13)Permission denied: AH00072: make_sock: could not bind to address [::]:8888
(13)Permission denied: AH00072: make_sock: could not bind to address 0.0.0.0:8888

Add port with selinux Reference http://hetarena.com/archives/495

$ semanage port -a -t http_port_t -p tcp 8888

Build an environment for your application

$ vi /etc/httpd/conf.d/myenv.conf

myenv.conf

<VirtualHost *:8888>
    WSGIDaemonProcess wsgi_flask user=apache group=apache threads=10
    WSGIScriptAlias / /var/www/myapp/app.wsgi

    WSGIScriptReloading On

    <Directory "/var/www/myapp">
	WSGIProcessGroup wsgi_flask
	WSGIApplicationGroup %{GLOBAL}
        Order deny,allow
        Allow from all
    </Directory>
</VirtualHost>

--Check the configuration file

$ apachectl configtest

https://deep-blog.jp/engineer/12317/

$ service httpd graceful

Install mysql

$ sudo su
$ rpm -Uvh https://repo.mysql.com/mysql80-community-release-el7-3.noarch.rpm
$ yum install mysql-community-server
$ service mysqld start
$ service mysqld status #Confirmation

mysql login

$ sudo su
$ tail /var/log/mysqld.log #Check password from log
$ mysql -uroot
$ mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH caching_sha2_password BY 'YQM3rCyae8Ft?';

Reference https://dev.classmethod.jp/articles/how-to-serve-flask-with-apache-mod_wsgi-virtualenv-on-ec2/