I have an Ubuntu instance on Google Cloud Platform (GCP). I want to use it as an HTTP server to access files. I simply use this python command, type it in bash:
python3 -m http.server 8000
This will run http.server module as a script, construct a simple HTTP server and listen at port 8000.
Problem is that, since I use GCP instance, I must connect to it remotely (for example I use SSH shell provided by GCP). When I close the SSH shell, the python HTTP server will stop. So what should I do to make sure that the server still runs after I close the shell?
I did searched on Google, and I tried to use
nohup python3 -m http.server 8000 &
This command, I quote, will run the instruction as a background program and persist running after exiting bash. But it seems that this doesn't work for my situation.
Anybody can help?
Try the screen command. I think it's easier to use and also more flexible than nohup as you can also reattach processes after detaching then. See this answer for details.
The http.server module is not meant to be a full-fledged webserver.
You'll want to set up something like Apache instead, see Running a basic Apache web server.
Related
Using fabric 2.4 and trying to set up ssh keys to remotely connect to various linux servers?
Python is new to me, I've followed example on this site and Read python doc but still unclear to me.
Currently running python on windows and my script is able to connect to remote linux servers because i have connection string defined as follows:
ssh_connect = Connection(host='servername', user='user1', connect_kwargs={'password': 'blahblah'})
I am running python script from my window server and instead of defining the connection string, I would like it to use ssh key. I have the id_rsa.pub file from the linux server. I would like to setup up on my windows box and have the script use that for connections?
You can always just pass a key via Fabric through it's command line arguments. This is definitely kind of a vague question, especially since it's running fabric on Windows, which to my knowledge is not technically supported by them, though it does work.
fab -i /Path/to/key
Source: fab --help and the official documentation here
I am trying to run a Python app in Google App Engine. The UI doesn't work so I tried using the command lines. I tried restarting my PC, I tried changing port with "dev_appserver.py --port=9999 ." but it still says Unable to bind localhost:8000:
raise BindError('Unable to bind %s:%s' % self.bind_addr)
google.appengine.tools.devappserver2.wsgi_server.BindError: Unable to bind localhost:8000
The app server starts two servers; one for your application, the other for the development console. It is that second server that is causing the problem here; it normally would be run on port 8000.
Change the ip address for the development console with the --admin_port switch:
dev_appserver.py --admin_port=9000
You may still want to change the port for the main application server too, of course.
Also see the command-line arguments documentation for dev_appserver.py.
It is possible some application is binding to your port in autostart event.
It's highly probable to be the same service you are trying to run. In that case try killing the process
ps -ef | grep 'process_name'
Use kill -9 'pid' to end the process.
A computer restart did it, closing google app engine launcher, restarting the computer then launching again did the trick...
terminate old terminal and start in new, its the easiest way I
could find
Being unable a port is usually a sign of one of two things:
You don't have permissions
Something is already running there.
You can try hitting the local port 8080 with your browser to see what is there, and kill it if it shouldn't be.
As for permissions - only look for this afterwards. Presuming you are in windows (you didn't specify this), then you should be able to bind this as a normal user.
As for the command line - have you tried replacing the "=" with a space - I've seen both forms in documentation for app-engine.
dev_appserver.py --port 9999 .
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 written a simple automation script for deploying and restarting my twisted application on remote Debian host. But I have an issue with starting using twistd.
I have a run.tac file and start my application as follows inside fabric task:
#task
def start():
run("twistd -y run.tac")
And then just fab -H host_name start. It works great on localhost but when I want to start application on remote host I get nothing. I can see in log file that application is actually launched, but factory is not started. I've also checked netstat -l - nothing is listening my port.
I've tried to run in non-daemon mode, like so twistd -ny run.tac, and, voila, factory started and I can see it in netstat -l on remote host. But that is not the way I want it to work cause it. Any help is appreciated.
There was an issue reported sometime back which is similar to this.
Init scripts frequently fail to start their daemons
init-scripts-dont-work
It also suggested that it seems to succeed with the option pty=False. Can you try and check that?
run("twistd -y run.tac", pty=False)
Some more pointers from the FaQ:
why-can-t-i-run-programs-in-the-background-with-it-makes-fabric-hang
I'm looking to use a local webserver to run a series of python scripts for the user. For various unavoidable reasons, the python script must run locally, not on a server. As a result, I'll be using HTML+browser as the UI, which I'm comfortable with, for the front end.
I've been looking, therefore, for a lightweight web server that can execute python scripts, sitting in the background on a machine, ideally as a Windows service. Security and extensibility are not high priorities as it's all running internally on a small network.
Should I run a native python webserver as a Windows service (in which case, how)? Or is it just as easy to install Apache onto the user's machine and run as CGI? Since this is all local, performance is not an issue either.
Or am I missing something obvious?
Don't waste a lot of time creating Windows service.
Don't waste a lot of time on Windows Apache.
Just make a Python service that responds to HTTP requests.
Look at https://docs.python.org/2/library/basehttpserver.html
https://docs.python.org/3/library/http.server.html for version 3
Python offers an HTTP server that you can extend with your server-side methods.
Look at http://docs.python.org/library/wsgiref.html
Python offers a WSGI reference implementation that makes your server easy and standards-compliant.
Also http://fragments.turtlemeat.com/pythonwebserver.php
"I'm trying to avoid making the user run python stuff from the command prompt."
I don't see how clicking a web page is any different from clicking desktop icons.
Starting a web server based on Python is relatively easy, once you have the web server. First, build the server. Later, you can make sure the server starts. Let's look at some ways.
Your user can't use a random browser to open your local page. They need a bookmark to launch "localhost:8000/myspecialserverinsteadofthedestop/" That bookmark can be a .BAT file that (1) runs the server, (2) runs firefox with the proper initial URL.
You can put the server in the user's start-this menu.
You can make your Python program a windows "service".
Best way is to make your own local server by using command prompt.
Make a new folder say Project
Make a new folder inside project & name it as "cgi-bin"(without quotes)
Paste your .py file inside the cgi-bin folder
Open cmd and change to the directory from which you want to run the server and type "python -m CGIHTTPServer"(without quotes)
Minimize the cmd window & open your browser and type "localhost:8000/cgi-bin/yourpythonfilename.py"(without quotes).
The wasiest step would be navigate to folder where your files are located and running http.server module
cd /yourapp
python3 -m http.server
the you should see something like this in console
Serving HTTP on 0.0.0.0 port 8000 (http://0.0.0.0:8000/) ...
Running a native python webserver as a windows service should be a no brainer. Check out the documentation for writing windows services (win32api, ActiveState python) in python and also the documentation for subclassing BaseHttpServer and SimpleHttpServer.
BTW: I had a similar question on stackoverflow: How to stop BaseHTTPServer.serve_forever() in a BaseHTTPRequestHandler subclass?
Basically, you subclass BaseHTTPServer (you have to anyway...) and then... but just read the accepted answer - it set me on the right track!