How to start redis from with flask app.py?

[scheung38]

Instead of launching redis from command line with :

sudo service redis_6379 start

how to do this within Python, thanks.

[mjhea0]

You could do something as easy as-

import os
os.system("service redis_6379 start'")

but I think a fabfile would be the way to go. Fabric

[scheung38]

Thanks Michael, if this is such an important task, not sure why most tutorials tell user to manually start in command line instead of doing this before every session?

[mjhea0]

Because it's a a process that should already running. Think of when you connect to postgres. You don't manually start the server for each session. Instead, you run it in the background. If I were you, I would simply set up a try/except block to test for the connection first, rather than writing a script to open the connection itself.

[scheung38]

But it is to be deployed to AWS, so it may probably not be already running. I would have assumed that we need to launch it if it is not already running in the background?

import os
os.system("service redis_6379 restart")

returns

*** FATAL CONFIG FILE ERROR ***
Reading the configuration file, at line 104
>>> 'logfile /var/log/redis_6379.log'
Can't open the log file: Permission denied
 * Running on http://127.0.0.1:5000/
 * Restarting with reloader
/var/run/redis_6379.pid does not exist, process is not running
Starting Redis server...

*** FATAL CONFIG FILE ERROR ***
Reading the configuration file, at line 104
>>> 'logfile /var/log/redis_6379.log'
Can't open the log file: Permission denied

and

import os
os.system("sudo service redis_6379 restart")

returns

sudo: no tty present and no askpass program specified
 * Running on http://127.0.0.1:5000/
 * Restarting with reloader
sudo: no tty present and no askpass program specified

[mjhea0]

http://stackoverflow.com/a/24107529/1799408

[scheung38]

So is it straight forward to have redis (mongod or any other database servers) running on AWS or Heroku?

[scheung38]

So AWS can easily deploy redis? if so how would you define that thanks

[mjhea0]

https://aws.amazon.com/elasticache/

[nirorman]

https://stackoverflow.com/questions/24374490/amazon-elasticcache-redis-public-access#answer-25913518 You can't access AWS Elastic Cache from outside aws, so you can't use that redis when developing locally.