I have a Django AWS server that I need to keep running over the weekend for it to be graded. I typically start it from an SSH using PuTTY with:
python manage.py runserver 0.0.0.0:8000
I was originally thinking of making a bash script to do the task of starting the server, monitoring it, and restarting it when needed using the but was told it wasn't going to work. Why?
1) Start the server using python manage.py runserver 0.0.0.0:8000 & to send it to the background
2) After <some integer length 'x'> minutes of sleeping, check if the server isn't up using ss -tulw and grep the result for the port the server should be running on.
3) Based on the result from step (2), we either need to sleep for 'x' minutes again, or restart the server (and possibly fully-stop anything left running beforehand).
Originally, I thought it was a pretty decent idea, as we can't always be monitoring the server.
EDIT: Checked that ss -tulw | grep 8000 correctly grabs the server while running server:
if I understand you correctly, this is a non-production Django app. You could run a test server using Django's development server like python manage.py runserver 0.0.0.0:8000 as you did.
Thinks like monit (https://mmonit.com/monit/) or supervisord (http://supervisord.org/) are meant to do what you described - monitoring a process and restart it if necessary, but you could also just use a cron job that runs perhaps every minute. In the cron job, you:
Check whether your process is still running and or still listening on port 8000.
Abort if already running.
Restart if stopped or not listening to port 8000.
Related
I have setup a Django project on a virtual environment on my PC. When using the command
python manage.py runserver 0.0.0.0:8000
Bit Bash stops doing anything and I have to end the program to start over. I have waited several minutes and when I end the session, a dialogue says:
Processes are running in session:
WPID PID COMMAND
14904 1534 c:\Users\mine\AppData\Loca
Close anyway?
I have looked at every related question to this and tried every solution but I cannot get this to work, on or off the virtual environment.
Not sure if this applies, but I also noticed that in my task manager, python3.9.exe appears twice when trying to start the server. The status says running, and the PIDs are different numbers.
This is because something already running on port 8000. You can run the Django server by hosting on another port like 8080 but, you can also kill the already running task on the port. Follow the link to know how exactly you can kill any running process.
It is highly likely that another application is running using the port 8000. Try running the server using another port, say 8088 and share if the same issue persists.
To run on specific port kill all pids which is showing you on Git bash
(ps -ef)... kill them using (kill -9 pid_no)... then run your runserver command.
Ex:
ps -ef
kill -9 123
I ended up paying someone to fix this. Here is the conversation I had with the person who found the issue. Hope this helps someone out there.
Also, I noticed sometimes it still does freeze up on the watching for file changes with StateReloader until I go the browser and type in http://localhost:8000/. Once I do that the rest of the text loads and my browser shows The install worked successfully! Congratulations!
it works, what did you do?
- We have existing processes on port 8000.I think, you had the server running and kept trying over and over. So, I killed process using 8000 port.
- Next, I run Django project again.
- So, now it's working well.
ok. Can you tell me what you did at the start to make it work? Or was it always working?
- I started git bash session again when I started. Maybe git bash session had problems.
But this was going on for a day, I restarted the computer several times and restarted git bash. Same issue.
You must have done something.
- Sorry, I didn't do anything except restart git bash
how did you restart it?
- right click top of window, select NEW
How do I turn server off?
- press Ctrl + C
- And you didn't quit the server exactly before. Maybe you closed git bash directly and server was still live
- So, we had many 8000 ports.
Ok. How can I see what is on that port now?
- You can use this cli
- netstat -ano | findstr :<PORT>
- We don't have running 8000 port now.
I have never found solutions to this problem even with killing ports, changing port etc.
It never display the following part:
Starting development server at http://127.0.0.1:8000/
However, when I use the Git Bash terminal include into vscode, it displays the url.
Terminal > New Terminal > then:
Result :
python manage.py runserver 127.0.0.1:8080
I haven't yet been able to get Apache working with my Django app, so until I do get it working, I'm using runserver on my Linux server in order to demo the app. The problem is that whenever I close the SSH connection to the server, runserver stops running. How can I keep runserver running when I say put my laptop to sleep, or lose internet connectivity?
P.S. I'm aware that runserver isn't intended for production.
Using Screen
You can run runserver in a screen session. After you detach from that session it will keep running. Login via ssh and start a screen session via
screen
It will look like your usual terminal. Now, run the server
python manage.py runserver 8080
After this, you can detach from the session using Ctrl+a Ctrl+d. Now your app should be available even after you quit your ssh session.
If you want to cancel the runserver, you can re-atach to your screen session. Get a list of existing sessions with
screen -ls
There is a screen on:
10989.pts-1.hostname (Detached)
1 Socket in /run/screens/S-username.
Then, you can reatach with the command
screen -R 10989
Using nohup
Again, after login into your server, start the runserver with
nohup python manage.py runserver 8080 &
All output the runserver writes (like debug info and so on) will be written to a file called nohup.out in the same folder.
To quit the server after using nohup you need to keep the process id (pid) shown or find the pid afterwards with ps, top or any other tool.
Since runserver isn't intended to be ran in production/only for development there is no way to to this built in.
You will need to use a tool like tmux/screen or nohup to keep the process alive, even if the spawning terminal closes.
$ nohup python manage.py runserver &
nohup makes command ignore hangup signal and & puts in to background disconnecting from stdout
If you are SSH'ing through to your server and starting Django there, consider use of a program on the server such as tmux. This will allow your server-side shell process to remain alive after disconnection, and you can reattach on your next login with a simple
tmux attach
command.
I have a remote server through Blue Host that's intended to run a server based on Twisted for Python. The only access I have to it is over SSH, so to keep Python running after I log out I tried using nohup python server.py & and screen -dm python server.py, getting the same results for each. Everything works fine until I log out of SSH - even though Python is running in the background as expected, once I've logged out, my client can no longer communicate with the server. The strange part is that if I log back in over SSH and check the running processes with ps aux, I see Python running and my client can successfully communicate with the server again. Even if I don't type anything at all once I log back in, everything works as expected. But, of course, as soon as I log back out, it's as if the server is gone.
I've contacted support for the hosting service in case this is some oddity on their end, but hopefully this is something that can be resolved on my end instead.
Edit: Looks like Blue Host doesn't want me doing server-y stuff without buying the VPS upgrade so it looks like that's the big problem.
Edit 2: Okay, so in case anybody ends up having a similar problem, here's what the main issue turned out to be. I was mistaken in my original description; I was able to connect to the server but I was getting kicked off immediately for what turned out to be a MySQL error. I guess trying to connect to a localhost database with no active connection somehow causes problems, so instead I changed the MySQL connection command to connect to my site's IP address instead, even though it was the same IP as the server. That seemed to do the trick in terms of my main issue.
Don't use this method to keep the server process running. Instead try using supervisor (apt-get install supervisor). It allows you to daemonize your process, and ability to stop/restart etc.
Here's a sample config entry (/etc/supervisor/supervisord.conf):
[program:my_server]
command=python /path/to/server/server.py
directory=/path/to/server/
autostart=true
autorestart=true
stdout_logfile=/var/log/server.log
stderr_logfile=/var/log/server_error.log
user=your_linux_user_name
After you edit your config, do
sudo service supervisor stop
sudo service supervisor start #need to do this - doing a `restart` doesn't reload the config file!
your server should now be running properly. You can manage its lifecycle via sudo supervisorctl
I have an instance on google compute engine, connecting to it by terminal: gcutil ssh, on it I have several DJango servieces. I run the server using: python manage.py runserver 0.0.0.0:8000. the services are being called from an iPhone application IOS 6.1
the problem I'm facing is that every few minutes (between 10- 15) I'm getting disconnected and have to reconnect and run the server again.
Why is my server being disconnected and how can I keep the it running?
Try using supervisor.d. It sounds like for what your trying to do, supervisor can keep your process up and running. http://supervisord.org/
Here's an example conf:
[program:app]
process_name = app-%(process_num)s
command =python /home/ubuntu/production/current/app/src/app.py --port=%(process_num)s
# Increase numprocs to run multiple processes on different ports.
# Note that the chat demo won't actually work in that configuration
# because it assumes all listeners are in one process.
numprocs = 4
numprocs_start = 8000
This is for running multiple processes of the same program. Just change around the args and it should work for you.
SSH normally times out after a period of inactivity, and that may be what is happening here. If so, this article might be useful to help configure SSH to send a regular message so connections are less likely to be dropped.
However, the core issue is that you'd like software you started at the terminal to keep running even when you're logged out. Consider using screen or tmux to host your shell sessions. This will allow your shell software to run even when you are not connected, and for you to pick up right where you left off when you reconnect. Here is a nice getting started post about tmux.
Once you're ready for production, take a look at the Django deployment docs.
django-admin.py runserver is running while developing. I have an open webpage connected to my sse endpoint.
Seems like using django-sse breaks to server autoreload feature, cf. this issue.
What's worse is that if I manually restart the server (Ctr+C & django-admin.py runserver), it fails with a 'port already in use error' and I need to ps grep runserver kill whatever_id first, a true PITA.
So:
How comes using persistent connections breaks my dev workflow ?
Is there an easy workaround not involving patching django ?
In production I'm using a Procfile with foreman to launch gunicorn gevent workers. Here a manual restart goes fine (open connections are closed) but there's not autoreload feature nor any log printed in the terminal.