I have two python files.
server1.py
from flask import Flask
app = Flask(__name__)
@app.route('/')
def home():
return "Hello world from server 1."
if __name__ == "__main__":
app.run(port=3000)
server2.py
from flask import Flask
app = Flask(__name__)
@app.route('/')
def home():
return "Hello from server 2."
if __name__ == "__main__":
app.run(port=4000)
Now, I need to run these two servers at the same time using a bash script.
I have tried this in my bash script.
python3 server1.py && python3 server2.py
When I run this bash script, it runs the server1.py file only when I quit server 1 it runs the server2.py
Output of my bash script:
* Serving Flask app 'server1' (lazy loading)
* Environment: production
WARNING: This is a development server. Do not use it in a production deployment.
Use a production WSGI server instead.
* Debug mode: off
* Running on http://127.0.0.1:3000 (Press CTRL C to quit)
^C * Serving Flask app 'server2' (lazy loading)
* Environment: production
WARNING: This is a development server. Do not use it in a production deployment.
Use a production WSGI server instead.
* Debug mode: off
* Running on http://127.0.0.1:4000 (Press CTRL C to quit)
I think its not possible to run two flask servers same time in a single terminal.
Is there any way using bash we can open a new terminal and run the server2.py file on that terminal? for some reasons, I need to run both flask servers same time.
CodePudding user response：
hope you are doing well,
Thank you for providing the scripts and servers configuration. With these I was able to reproduce what you got.
So
I think there is multiple solutions but I will give you two of them:
The first is to deploy your servers into docker containers and run them either with a bash script or with docker-compose or in other container platforms.
the second is, instead of using "&&" at the end of the command "python3 server1.py" that means "execute what comes after this only if what is before is executed and successful, you can just use "&" that means "execute what is before in the background and execute what is next in the same time. here is the bash script:
script.sh:
#/bin/bash
python3 server1.py &
python3 server2.py
it worked well for me but the problem with this is that even when you "ctrl-c" on your bash script output, the server2 will stop but not the server1:
❯ ps -aux
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
...
bguess 21149 0.0 0.2 178708 26480 pts/3 S 00:48 0:00 python3 server1.py
...
you will have to kill it manually with kill "PID_HERE" (kill 21149 in my example.)
Instead here is the solution with docker: First lets modify your servers to listen on all host on port 4000 (since server1 and server2 will be isolated in 2 differents containers there will be no conflicts)
server1.py:
from flask import Flask
app = Flask(__name__)
@app.route('/')
def home():
return "Hello world from server 1."
if __name__ == "__main__":
app.run(port=4000, debug=True, host='0.0.0.0')
server2.py:
from flask import Flask
app = Flask(__name__)
@app.route('/')
def home():
return "Hello from server 2."
if __name__ == "__main__":
app.run(port=4000, debug=True, host='0.0.0.0')
Next, lets write down the two dockerfiles needed to build your containers images:
but first here is the requirements.txt file we will copy into our docker images:
requirements.txt:
flask
dockerfile1:
FROM python:3.8-slim-buster
WORKDIR /app
COPY requirements.txt requirements.txt
RUN pip3 install -r requirements.txt
COPY server1.py .
CMD [ "python3", "-m" , "server1", "run", "--host=0.0.0.0:4000"]
EXPOSE 4000
dockerfile2:
FROM python:3.8-slim-buster
WORKDIR /app
COPY requirements.txt requirements.txt
RUN pip3 install -r requirements.txt
COPY server1.py .
CMD [ "python3", "-m" , "server1", "run", "--host=0.0.0.0:4000"]
EXPOSE 4000
Now lets build the docker images from this 2 dockerfiles:
docker build -t so-flask-s1 -f dockerfile1 .
docker build -t so-flask-s2 -f dockerfile2 .
Now lets run our containers:
❯ docker run --rm -d -p 8081:4000 --name server1 so-flask-s1
7cfb16a63cd6de6ff2ecb9d728302a9f9ef0a848ab81a5cedf6ce9f60eaa66ae
❯ docker run --rm -d -p 8082:4000 --name server2 so-flask-s2
209013ba82f8c701ba46fd67675b9151056921a5a8b5a916e7f29b9014e7c9a1
Lets check if they are both running:
❯ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS
NAMES
209013ba82f8 so-flask-s2 "python3 -m server2 …" 3 seconds ago Up 2 seconds 0.0.0.0:8082->4000/tcp server2
7cfb16a63cd6 so-flask-s1 "python3 -m server1 …" 10 seconds ago Up 9 seconds 0.0.0.0:8081->4000/tcp server1
Now, lets check our browser:
Hope this has helped you.
delete the images with: docker rmi #exemple: docker rmi so-flask-s2
kill the containers with: docker kill #example: docker kill server2
here is a little cheat sheet (but you can find plenty of them on the internet): https://www.docker.com/wp-content/uploads/2022/03/docker-cheat-sheet.pdf
bguess
CodePudding user response：
I agree with @gordon-davisson, about the connector. But, if you are looking for a bash script to run your server, with different port configuration, it's better to use the flask run command line utility provided with the flask package.
Also, you don't need to change the port manually in the script, in case you again want to change the port, or the configuration i.e debug=True/False or the hostname=0.0.0.0 or 127.0.0.1
Some basics of it are (from it's help description):
flask run --help
Usage: flask run [OPTIONS]
Run a local development server.
This server is for development purposes only. It does not provide the
stability, security, or performance of production WSGI servers.
The reloader and debugger are enabled by default if FLASK_ENV=development
or FLASK_DEBUG=1.
Options:
-h, --host TEXT The interface to bind to.
-p, --port INTEGER The port to bind to.
--cert PATH Specify a certificate file to use HTTPS.
--key FILE The key file to use when specifying a
certificate.
--reload / --no-reload Enable or disable the reloader. By default
the reloader is active if debug is enabled.
--debugger / --no-debugger Enable or disable the debugger. By default
the debugger is active if debug is enabled.
--eager-loading / --lazy-loader
Enable or disable eager loading. By default
eager loading is enabled if the reloader is
disabled.
--with-threads / --without-threads
Enable or disable multithreading.
--extra-files PATH Extra files that trigger a reload on change.
Multiple paths are separated by ':'.
--help Show this message and exit.
You can find great info on this topic at flask run command