Difference between revisions of "Flask"

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Line 1: Line 1:
−
=basics=
+
=Basics=
 
Check this[https://flask.palletsprojects.com/en/1.1.x/quickstart/]
 
Check this[https://flask.palletsprojects.com/en/1.1.x/quickstart/]
  
Line 12: Line 12:
 
@app.route('/')
 
@app.route('/')
  
−
def main():
+
def welcome():
−
     return 'Hello World'
+
     return 'Welcome'
  
−
if __name__ == '__main__':
+
if __name__ == '__main__':         # When executed on the commandline (build in webserver)
−
     app.run() # Default (listen to localhost port 5000, use flash run for options)
+
     app.run(host='0.0.0.0',port=5000) # Listen to localhost port 5000, you can also use flask run for options
 
     #app.run(host='0.0.0.0',port=8080,Debug=True)  # Run in debug mode, listen to all hosts on port 8080
 
     #app.run(host='0.0.0.0',port=8080,Debug=True)  # Run in debug mode, listen to all hosts on port 8080
  
Line 33: Line 33:
 
https://code.tutsplus.com/tutorials/creating-a-web-app-from-scratch-using-python-flask-and-mysql--cms-22972
 
https://code.tutsplus.com/tutorials/creating-a-web-app-from-scratch-using-python-flask-and-mysql--cms-22972
  
−
=templates=
+
=Integrate with nginx=
 +
 
 +
Mayor part is from this site [https://vladikk.com/2013/09/12/serving-flask-with-nginx-on-ubuntu/].
 +
 
 +
* Install uwgi-emperor and it's python plugin
 +
Configuration files I used.
 +
 
 +
:* Generic configuration file (/etc/uwsgi-emperor/emperor.ini):
 +
[uwsgi]
 +
# try to autoload appropriate plugin if "unknown" option has been specified
 +
autoload = true
 +
# enable master process manager
 +
master = true
 +
# spawn 2 uWSGI emperor worker processes
 +
workers = 2
 +
# automatically kill workers on master's death
 +
no-orphans = true
 +
# place timestamps into log
 +
log-date = true
 +
# user identifier of uWSGI processes (same as who runs the web-server)
 +
uid = www-data
 +
# group identifier of uWSGI processes (same as who runs the web-server)
 +
gid = www-data
 +
# vassals directory
 +
emperor = /etc/uwsgi-emperor/vassals
 +
plugins = python3
 +
 
 +
:* Application configuration file (/etc/uwsgi-emperor/vassals/welcome.ini)
 +
 
 +
[uwsgi]
 +
#application's base folder
 +
base = /var/www/flask
 +
#python module to import
 +
app = welcome
 +
module = %(app)
 +
pythonpath = %(base)
 +
#socket file's location
 +
socket = /var/local/uwsgi/%n.sock
 +
#permissions for the socket file
 +
chmod-socket    = 664
 +
#the variable that holds a flask application inside the module imported at line #6
 +
callable = app
 +
#location of log files
 +
logto = /var/log/uwsgi/%n.log
 +
plugins = python3
 +
 
 +
* Create a virtual webserver (port 80 is save enough if you have a secure front-end server)
 +
 
 +
<syntaxhighlight lang="nginx">
 +
server {
 +
listen 80 ;
 +
listen [::]:80 ;
 +
 
 +
root /var/www/flask;
 +
 
 +
server_name <fqdn>;
 +
 
 +
location / {
 +
include uwsgi_params;
 +
        uwsgi_pass unix:/var/local/uwsgi/welcome.sock;
 +
}
 +
}
 +
</syntaxhighlight>
 +
 
 +
=Generate web pages=
 
https://flask.palletsprojects.com/en/1.1.x/patterns/templateinheritance/#template-inheritance
 
https://flask.palletsprojects.com/en/1.1.x/patterns/templateinheritance/#template-inheritance
  
−
=Integrate with nginx=
+
 
−
https://vladikk.com/2013/09/12/serving-flask-with-nginx-on-ubuntu/
+
[https://www.idkrtm.com/creating-a-webpage-using-python-and-flask/ Source for this basic app]
 +
 
 +
Put a index.html in <app-base>/templates/
 +
 
 +
<syntaxhighlight lang=python>
 +
#!/usr/bin/env python3
 +
 
 +
from flask import Flask, render_template
 +
 
 +
print(__name__)
 +
app = Flask(__name__)
 +
 
 +
@app.route('/html')
 +
def static_page():
 +
  return render_template('index.html')
 +
 
 +
if __name__ == '__main__':
 +
    app.run(host='0.0.0.0',port=5000,debug=True)
 +
 
 +
</syntaxhighlight>
 +
 
 +
=Microservices and/or more applications on 1 web-server=
 +
 
 +
Starting with [https://jawher.me/multiple-python-apps-with-nginx-uwsgi-emperor-upstart/ this page] and additional a lot more we got it working on [https://www.raspberrypi.org/software/ raspberry pi debian].
 +
 
 +
# Make python3 the default<br><code>cd /usr/bin;rm python;ln -s python3 python</code>
 +
# Install uwsgi and python plugin<br><code>apt install uwsgi uwsgi-plugin-python3</code>
 +
# install nginx<br><code>apt install nginx-full</code>
 +
I had to make a small change in the nginx configuration;<br>
 +
<code>vi /etc/nginx/conf.d/my.conf<br>
 +
server_names_hash_bucket_size 64;
 +
</code>
 +
 
 +
===Super simple apps===
 +
In /var/www/flask/app1/app1/py
 +
<syntaxhighlight lang=python>
 +
#!/usr/bin/env python3
 +
 
 +
from flask import Flask
 +
import os
 +
 
 +
application = Flask(__name__)
 +
 
 +
@application.route('/app1')
 +
def app1():
 +
    return "App 1 live and kicking"
 +
 
 +
if __name__ == '__main__':
 +
    application.run(host='0.0.0.0', port=8080,debug=True)
 +
</syntaxhighlight>
 +
 
 +
/var/www/flask/app2/app2.py
 +
<syntaxhighlight lang=python>
 +
#!/usr/bin/env python3
 +
 
 +
from flask import Flask
 +
import os
 +
 
 +
application = Flask(__name__)
 +
 
 +
@application.route('/app2')
 +
def app2():
 +
    return "App 2 live and kicking"
 +
 
 +
if __name__ == '__main__':
 +
    application.run(host='0.0.0.0', port=8080,debug=True)
 +
</syntaxhighlight>
 +
 
 +
===uwsgi configuration===
 +
 
 +
/etc/uwsgi/apps-available/emperor.xml
 +
<syntaxhighlight lang=xml>
 +
<uwsgi>
 +
  <autoload>true</autoload>
 +
  <no-orphan>true</no-orphan>
 +
  <emperor>/etc/uwsgi/vassals-enabled</emperor>
 +
  <master>true</master>
 +
  <emperor-nofollow>true</emperor-nofollow>
 +
  <processes>1</processes>
 +
  <uid>www-data</uid>
 +
  <gid>www-data</gid>
 +
</uwsgi>
 +
</syntaxhighlight>
 +
 
 +
/etc/uwsgi/apps-available/apps.xml
 +
<syntaxhighlight lang=xml>
 +
<uwsgi>
 +
  <plugins>python3</plugins>
 +
  <master>false</master>
 +
  <processes>1</processes>
 +
  <vaccum>true</vaccum>
 +
  <chmod-socket>666</chmod-socket>
 +
  <socket>/tmp/%n.sock</socket>
 +
  <uid>www-data</uid>
 +
  <gid>www-data</gid>
 +
  <pythonpath>/var/www/flask/%n</pythonpath>
 +
  <module>%n</module>
 +
</uwsgi>
 +
</syntaxhighlight>
 +
 
 +
Make them available
 +
<syntaxhighlight lang=bash>
 +
cd /etc/uwsgi/apps-enabled
 +
ln -s ../apps-available/emperror.xml
 +
cd /etc/uwsgi/vassals-enabled
 +
ln -s ../apps-available/apps.xml app1.xml
 +
ln -s ../apps-available/apps.xml app2.xml
 +
</syntaxhighlight>
 +
 
 +
===Create a nginx virtual host===
 +
 
 +
/etc/nginx/sites-enabled/apps.conf
 +
 
 +
<syntaxhighlight lang=nginx>
 +
server {
 +
  listen 80;
 +
  server_name <your webserver fdqn>;
 +
  index index.html;
 +
 
 +
  root /var/www/flask;
 +
 
 +
  location /app1 {
 +
    include uwsgi_params;
 +
    uwsgi_param SCRIPT_NAME /app1;
 +
    uwsgi_modifier1 30;
 +
    uwsgi_pass unix://tmp/app1.sock;
 +
  }
 +
 
 +
  location /app2 {
 +
    include uwsgi_params;
 +
    uwsgi_param SCRIPT_NAME /app2;
 +
    uwsgi_modifier1 30;
 +
    uwsgi_pass unix://tmp/app2.sock;
 +
  }
 +
}
 +
</syntaxhighlight>
 +
 
 +
===Start things===
 +
service uwsgi start
 +
service nginx start
 +
 
 +
That's it. Point your webbrowser to http://<your webserver fdqn>/app1
 +
 
 +
Optimization still to be done. I think I start on [https://www.techatbloomberg.com/blog/configuring-uwsgi-production-deployment/ this place]

Revision as of 17:07, 21 November 2020

Basics

Check this[1]

Hello world app: 

#!/usr/bin/env python3

from flask import Flask
print(__name__)
app = Flask(__name__)

@app.route('/')

def welcome():
    return 'Welcome'

if __name__ == '__main__':         # When executed on the commandline (build in webserver)
    app.run(host='0.0.0.0',port=5000) # Listen to localhost port 5000, you can also use flask run for options
    #app.run(host='0.0.0.0',port=8080,Debug=True)  # Run in debug mode, listen to all hosts on port 8080

Run the build-in server listening to all 

export FLASK_APP=welcome_app.py 
flask run --host=0.0.0.0

welcome_app
 * Serving Flask app "welcome_app"
 * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)

Now you can browse to <serverIP>:5000

https://code.tutsplus.com/tutorials/creating-a-web-app-from-scratch-using-python-flask-and-mysql--cms-22972

Integrate with nginx

Mayor part is from this site [2].

  • Install uwgi-emperor and it's python plugin

Configuration files I used.

  • Generic configuration file (/etc/uwsgi-emperor/emperor.ini):
[uwsgi]
# try to autoload appropriate plugin if "unknown" option has been specified
autoload = true
# enable master process manager
master = true
# spawn 2 uWSGI emperor worker processes
workers = 2
# automatically kill workers on master's death
no-orphans = true
# place timestamps into log
log-date = true
# user identifier of uWSGI processes (same as who runs the web-server)
uid = www-data
# group identifier of uWSGI processes (same as who runs the web-server)
gid = www-data
# vassals directory
emperor = /etc/uwsgi-emperor/vassals
plugins = python3
  • Application configuration file (/etc/uwsgi-emperor/vassals/welcome.ini)
[uwsgi]
#application's base folder
base = /var/www/flask
#python module to import
app = welcome
module = %(app)
pythonpath = %(base)
#socket file's location
socket = /var/local/uwsgi/%n.sock
#permissions for the socket file
chmod-socket    = 664
#the variable that holds a flask application inside the module imported at line #6
callable = app
#location of log files
logto = /var/log/uwsgi/%n.log
plugins = python3
  • Create a virtual webserver (port 80 is save enough if you have a secure front-end server)
server {
	listen 80 ;
	listen [::]:80 ;

	root /var/www/flask;

	server_name <fqdn>;

	location / {
		include uwsgi_params;
        	uwsgi_pass unix:/var/local/uwsgi/welcome.sock;
	}
}

Generate web pages

https://flask.palletsprojects.com/en/1.1.x/patterns/templateinheritance/#template-inheritance


Source for this basic app

Put a index.html in <app-base>/templates/ 

#!/usr/bin/env python3

from flask import Flask, render_template

print(__name__)
app = Flask(__name__)

@app.route('/html')
def static_page():
  return render_template('index.html')

if __name__ == '__main__':
    app.run(host='0.0.0.0',port=5000,debug=True)

Microservices and/or more applications on 1 web-server

Starting with this page and additional a lot more we got it working on raspberry pi debian.

  1. Make python3 the default
    cd /usr/bin;rm python;ln -s python3 python
  2. Install uwsgi and python plugin
    apt install uwsgi uwsgi-plugin-python3
  3. install nginx
    apt install nginx-full

I had to make a small change in the nginx configuration;
vi /etc/nginx/conf.d/my.conf
server_names_hash_bucket_size 64;

Super simple apps

In /var/www/flask/app1/app1/py 

#!/usr/bin/env python3

from flask import Flask
import os

application = Flask(__name__)

@application.route('/app1')
def app1():
    return "App 1 live and kicking"

if __name__ == '__main__':
    application.run(host='0.0.0.0', port=8080,debug=True)

/var/www/flask/app2/app2.py 

#!/usr/bin/env python3

from flask import Flask
import os

application = Flask(__name__)

@application.route('/app2')
def app2():
    return "App 2 live and kicking"

if __name__ == '__main__':
    application.run(host='0.0.0.0', port=8080,debug=True)

uwsgi configuration

/etc/uwsgi/apps-available/emperor.xml 

 <uwsgi>
  <autoload>true</autoload>
  <no-orphan>true</no-orphan>
  <emperor>/etc/uwsgi/vassals-enabled</emperor>
  <master>true</master>
  <emperor-nofollow>true</emperor-nofollow>
  <processes>1</processes>
  <uid>www-data</uid>
  <gid>www-data</gid>
 </uwsgi>

/etc/uwsgi/apps-available/apps.xml 

 <uwsgi>
  <plugins>python3</plugins>
  <master>false</master>
  <processes>1</processes>
  <vaccum>true</vaccum>
  <chmod-socket>666</chmod-socket>
  <socket>/tmp/%n.sock</socket>
  <uid>www-data</uid>
  <gid>www-data</gid>
  <pythonpath>/var/www/flask/%n</pythonpath>
  <module>%n</module>
 </uwsgi>

Make them available 

cd /etc/uwsgi/apps-enabled
ln -s ../apps-available/emperror.xml
cd /etc/uwsgi/vassals-enabled
ln -s ../apps-available/apps.xml app1.xml
ln -s ../apps-available/apps.xml app2.xml

Create a nginx virtual host

/etc/nginx/sites-enabled/apps.conf 

server {
  listen 80;
  server_name <your webserver fdqn>;
  index index.html;

  root /var/www/flask;

  location /app1 {
    include uwsgi_params;
    uwsgi_param SCRIPT_NAME /app1;
    uwsgi_modifier1 30;
    uwsgi_pass unix://tmp/app1.sock;
  }

  location /app2 {
    include uwsgi_params;
    uwsgi_param SCRIPT_NAME /app2;
    uwsgi_modifier1 30;
    uwsgi_pass unix://tmp/app2.sock;
  }
}

Start things

service uwsgi start service nginx start

That's it. Point your webbrowser to http://<your webserver fdqn>/app1

Optimization still to be done. I think I start on this place

Retrieved from "https://wiki.antiperfect.org/index.php?title=Flask&oldid=973"