Python remote debugging with docker - python

I'm making a flask webapp with docker, I'm looking for a way to enable pycharm debugging, so far I'm able to deploy the app using the in built docker, the app is automatically ran due to the dockerfile configs using supervisord
When I connect my remote interpretor I get the usual:
* Running on http://0.0.0.0:80/ (Press CTRL+C to quit)
* Restarting with stat
* Debugger is active!
* Debugger PIN: 579-233-679
But the post I perform clearly isn't going to that interpretor as I've marked all of the routes to be break points, I'm still getting the original results from the webapp and none of the break points do anything.
I guess I'm asking:
Am I going about this the wrong way? (should I just use a VM, remote debug on that and then containerise the VM later on)
Is what I'm trying to do even possible?
Should I just manually debug everything instead if I use this method of development?

Update:
the way to correctly enable debug mode for docker is to create a docker-compose.yml, this tells pycharm what to do when you give it a docker-compose interpreter, that way you can hook onto a service, my yml looks like:
version: '3.0'
services:
web:
build: .
command: python3 app/main.py
volumes:
- .:/app
ports:
- "80:80"
- "22"
the yml file isn't generated, you make it yourself.
This enables the port that I've set flask to go to 80 and allows the debugger to connect using port 22,
I followed https://blog.jetbrains.com/pycharm/2017/03/docker-compose-getting-flask-up-and-running/ quite closely. (if anyone stumbles on to this and needs a hand then comment I'll see if I can help)

Related

ssh port forwarding with flask [duplicate]

I'm not sure if this is Flask specific, but when I run an app in dev mode (http://localhost:5000), I cannot access it from other machines on the network (with http://[dev-host-ip]:5000). With Rails in dev mode, for example, it works fine. I couldn't find any docs regarding the Flask dev server configuration. Any idea what should be configured to enable this?
While this is possible, you should not use the Flask dev server in production. The Flask dev server is not designed to be particularly secure, stable, or efficient. See the docs on deploying for correct solutions.
The --host option to flask run, or the host parameter to app.run(), controls what address the development server listens to. By default it runs on localhost, change it to flask run --host=0.0.0.0 (or app.run(host="0.0.0.0")) to run on all your machine's IP addresses.
0.0.0.0 is a special value that you can't use in the browser directly, you'll need to navigate to the actual IP address of the machine on the network. You may also need to adjust your firewall to allow external access to the port.
The Flask quickstart docs explain this in the "Externally Visible Server" section:
If you run the server you will notice that the server is only
accessible from your own computer, not from any other in the network.
This is the default because in debugging mode a user of the
application can execute arbitrary Python code on your computer.
If you have the debugger disabled or trust the users on your network,
you can make the server publicly available simply by adding
--host=0.0.0.0 to the command line:
$ flask run --host=0.0.0.0
This tells your operating system to listen on all public IPs.
If you use the flask executable to start your server, use flask run --host=0.0.0.0 to change the default from 127.0.0.1 and open it up to non-local connections.
If you run the server you will notice that the server is only
accessible from your own computer, not from any other in the network.
This is the default because in debugging mode a user of the
application can execute arbitrary Python code on your computer.
If you have the debugger disabled or trust the users on your network,
you can make the server publicly available simply by adding
--host=0.0.0.0 to the command line:
$ flask run --host=0.0.0.0
This tells your operating system to listen on all public IPs.
Reference: https://flask.palletsprojects.com/quickstart/
Try this if the 0.0.0.0 method doesn't work
Boring Stuff
I personally battled a lot to get my app accessible to other devices(laptops and mobile phones) through a local-server. I tried the 0.0.0.0 method, but no luck. Then I tried changing the port, but it just didn't work. So, after trying a bunch of different combinations, I arrived to this one, and it solved my problem of deploying my app on a local server.
Steps
Get the local IPv4 address of your computer.
This can be done by typing ipconfig on Windows and ifconfig on Linux
and Mac.
Please note: The above step is to be performed on the machine you are serving the app on, and on not the machine on which you are accessing it. Also note, that the IPv4 address might change if you disconnect and reconnect to the network.
Now, simply run the flask app with the acquired IPv4 address.
flask run -h 192.168.X.X
E.g. In my case (see the image), I ran it as:
flask run -h 192.168.1.100
On my mobile device
Optional Stuff
If you are performing this procedure on Windows and using Power Shell as the CLI, and you still aren't able to access the website, try a CTRL + C command in the shell that's running the app. Power Shell gets frozen up sometimes and it needs a pinch to revive. Doing this might even terminate the server, but it sometimes does the trick.
That's it. Give a thumbs up if you found this helpful.๐Ÿ˜‰
Some more optional stuff
I have created a short Powershell script that will get you your IP address whenever you need one:
$env:getIp = ipconfig
if ($env:getIp -match '(IPv4[\sa-zA-Z.]+:\s[0-9.]+)') {
if ($matches[1] -match '([^a-z\s][\d]+[.\d]+)'){
$ipv4 = $matches[1]
}
}
echo $ipv4
Save it to a file with .ps1 extension (for PowerShell), and run it on before starting your app. You can save it in your project folder and run it as:
.\getIP.ps1; flask run -h $ipv4
Note: I saved the above shellcode in getIP.ps1.
Cool.๐Ÿ‘Œ
Add host='0.0.0.0' to app.run`.
if __name__ == '__main__':
app.run(host='0.0.0.0', port=5000)
If you get OSError: [WinError 10013] An attempt was made to access a socket in a way forbidden by its access permissions on Windows, you either don't have permission to use the port, or something else is using it which you can find with netstat -na|findstr 5000.
Check whether the particular port is open on the server to serve the client or not?
in Ubuntu or Linux distro
sudo ufw enable
sudo ufw allow 5000/tcp //allow the server to handle the request on port 5000
Configure the application to handle remote requests
app.run(host='0.0.0.0' , port=5000)
python3 app.py & #run application in background
If your cool app has it's configuration loaded from an external file, like in the following example, then don't forget to update the corresponding config file with HOST="0.0.0.0"
cool.app.run(
host=cool.app.config.get("HOST", "localhost"),
port=cool.app.config.get("PORT", 9000)
)
If you're having troubles accessing your Flask server, deployed using PyCharm, take the following into account:
PyCharm doesn't run your main .py file directly, so any code in if __name__ == '__main__': won't be executed, and any changes (like app.run(host='0.0.0.0', port=5000)) won't take effect.
Instead, you should configure the Flask server using Run Configurations, in particular, placing --host 0.0.0.0 --port 5000 into Additional options field.
More about configuring Flask server in PyCharm
You can also set the host (to expose it on a network facing IP address) and port via environment variables.
$ export FLASK_APP=app.py
$ export FLASK_ENV=development
$ export FLASK_RUN_PORT=8000
$ export FLASK_RUN_HOST=0.0.0.0
$ flask run
* Serving Flask app "app.py" (lazy loading)
* Environment: development
* Debug mode: on
* Running on https://0.0.0.0:8000/ (Press CTRL+C to quit)
* Restarting with stat
* Debugger is active!
* Debugger PIN: 329-665-000
See How to get all available Command Options to set environment variables?
Go to your project path on CMD(command Prompt) and execute the following command:-
set FLASK_APP=ABC.py
SET FLASK_ENV=development
flask run -h [yourIP] -p 8080
you will get following o/p on CMD:-
Serving Flask app "expirement.py" (lazy loading)
Environment: development
Debug mode: on
Restarting with stat
Debugger is active!
Debugger PIN: 199-519-700
Running on http://[yourIP]:8080/ (Press CTRL+C to quit)
Now you can access your flask app on another machine using http://[yourIP]:8080/ url
For me i followed the above answer and modified it a bit:
Just grab your ipv4 address using ipconfig on command prompt
Go to the file in which flask code is present
In main function write app.run(host= 'your ipv4 address')
Eg:
Create file .flaskenv in the project root directory.
The parameters in this file are typically:
FLASK_APP=app.py
FLASK_ENV=development
FLASK_RUN_HOST=[dev-host-ip]
FLASK_RUN_PORT=5000
If you have a virtual environment, activate it and do a pip install python-dotenv .
This package is going to use the .flaskenv file, and declarations inside it will be automatically imported across terminal sessions.
Then you can do flask run
This answer is not solely related with flask, but should be applicable for all cannot connect service from another host issue.
use netstat -ano | grep <port> to see if the address is 0.0.0.0 or ::. If it is 127.0.0.1 then it is only for the local requests.
use tcpdump to see if any packet is missing. If it shows obvious imbalance, check routing rules by iptables.
Today I run my flask app as usual, but I noticed it cannot connect from other server. Then I run netstat -ano | grep <port>, and the local address is :: or 0.0.0.0 (I tried both, and I know 127.0.0.1 only allows connection from the local host). Then I used telnet host port, the result is like connect to .... This is very odd. Then I thought I would better check it with tcpdump -i any port <port> -w w.pcap. And I noticed it is all like this:
Then by checking iptables --list OUTPUT section, I could see several rules:
these rules forbid output tcp vital packets in handshaking. By deleting them, the problem is gone.
I had the same problem, I use PyCharm as an editor and when I created the project, PyCharm created a Flask Server. What I did was create a server with Python in the following way;
basically what I did was create a new server but flask if not python
I hope it helps you
This finally worked for me.
import os
Then place this at the end of your python app.py or main file.
if __name__ == "__main__":
port = int(os.environ.get("PORT", 5000))
app.run(host='0.0.0.0', port=port)
go to project path
set FLASK_APP=ABC.py
SET FLASK_ENV=development
flask run -h [yourIP] -p 8080
you will following o/p on CMD:-
* Serving Flask app "expirement.py" (lazy loading)
* Environment: development
* Debug mode: on
* Restarting with stat
* Debugger is active!
* Debugger PIN: 199-519-700
* Running on http://[yourIP]:8080/ (Press CTRL+C to quit)
If none of the above solutions are working, try manually adding "http://" to the beginning of the url.
Chrome can distinguish "[ip-address]:5000" from a search query. But sometimes that works for a while, and then stops connecting, seemingly without me changing anything. My hypothesis is that the browser might sometimes automatically prepend https:// (which it shouldn't, but this fixed it in my case).
In case you need to test your app from an external network.
Simply serve it to the whole Internet with ngrok.com
which will deploy it like a dev server but in no time and locally, saved me a lot of time, and no, I'm not related to that company :)
Just make sure to change the port in your flask app:
app.run(host='0.0.0.0', port=80)

Do WSGI servers connect to devices outside of the network? [duplicate]

I'm not sure if this is Flask specific, but when I run an app in dev mode (http://localhost:5000), I cannot access it from other machines on the network (with http://[dev-host-ip]:5000). With Rails in dev mode, for example, it works fine. I couldn't find any docs regarding the Flask dev server configuration. Any idea what should be configured to enable this?
While this is possible, you should not use the Flask dev server in production. The Flask dev server is not designed to be particularly secure, stable, or efficient. See the docs on deploying for correct solutions.
The --host option to flask run, or the host parameter to app.run(), controls what address the development server listens to. By default it runs on localhost, change it to flask run --host=0.0.0.0 (or app.run(host="0.0.0.0")) to run on all your machine's IP addresses.
0.0.0.0 is a special value that you can't use in the browser directly, you'll need to navigate to the actual IP address of the machine on the network. You may also need to adjust your firewall to allow external access to the port.
The Flask quickstart docs explain this in the "Externally Visible Server" section:
If you run the server you will notice that the server is only
accessible from your own computer, not from any other in the network.
This is the default because in debugging mode a user of the
application can execute arbitrary Python code on your computer.
If you have the debugger disabled or trust the users on your network,
you can make the server publicly available simply by adding
--host=0.0.0.0 to the command line:
$ flask run --host=0.0.0.0
This tells your operating system to listen on all public IPs.
If you use the flask executable to start your server, use flask run --host=0.0.0.0 to change the default from 127.0.0.1 and open it up to non-local connections.
If you run the server you will notice that the server is only
accessible from your own computer, not from any other in the network.
This is the default because in debugging mode a user of the
application can execute arbitrary Python code on your computer.
If you have the debugger disabled or trust the users on your network,
you can make the server publicly available simply by adding
--host=0.0.0.0 to the command line:
$ flask run --host=0.0.0.0
This tells your operating system to listen on all public IPs.
Reference: https://flask.palletsprojects.com/quickstart/
Try this if the 0.0.0.0 method doesn't work
Boring Stuff
I personally battled a lot to get my app accessible to other devices(laptops and mobile phones) through a local-server. I tried the 0.0.0.0 method, but no luck. Then I tried changing the port, but it just didn't work. So, after trying a bunch of different combinations, I arrived to this one, and it solved my problem of deploying my app on a local server.
Steps
Get the local IPv4 address of your computer.
This can be done by typing ipconfig on Windows and ifconfig on Linux
and Mac.
Please note: The above step is to be performed on the machine you are serving the app on, and on not the machine on which you are accessing it. Also note, that the IPv4 address might change if you disconnect and reconnect to the network.
Now, simply run the flask app with the acquired IPv4 address.
flask run -h 192.168.X.X
E.g. In my case (see the image), I ran it as:
flask run -h 192.168.1.100
On my mobile device
Optional Stuff
If you are performing this procedure on Windows and using Power Shell as the CLI, and you still aren't able to access the website, try a CTRL + C command in the shell that's running the app. Power Shell gets frozen up sometimes and it needs a pinch to revive. Doing this might even terminate the server, but it sometimes does the trick.
That's it. Give a thumbs up if you found this helpful.๐Ÿ˜‰
Some more optional stuff
I have created a short Powershell script that will get you your IP address whenever you need one:
$env:getIp = ipconfig
if ($env:getIp -match '(IPv4[\sa-zA-Z.]+:\s[0-9.]+)') {
if ($matches[1] -match '([^a-z\s][\d]+[.\d]+)'){
$ipv4 = $matches[1]
}
}
echo $ipv4
Save it to a file with .ps1 extension (for PowerShell), and run it on before starting your app. You can save it in your project folder and run it as:
.\getIP.ps1; flask run -h $ipv4
Note: I saved the above shellcode in getIP.ps1.
Cool.๐Ÿ‘Œ
Add host='0.0.0.0' to app.run`.
if __name__ == '__main__':
app.run(host='0.0.0.0', port=5000)
If you get OSError: [WinError 10013] An attempt was made to access a socket in a way forbidden by its access permissions on Windows, you either don't have permission to use the port, or something else is using it which you can find with netstat -na|findstr 5000.
Check whether the particular port is open on the server to serve the client or not?
in Ubuntu or Linux distro
sudo ufw enable
sudo ufw allow 5000/tcp //allow the server to handle the request on port 5000
Configure the application to handle remote requests
app.run(host='0.0.0.0' , port=5000)
python3 app.py & #run application in background
If your cool app has it's configuration loaded from an external file, like in the following example, then don't forget to update the corresponding config file with HOST="0.0.0.0"
cool.app.run(
host=cool.app.config.get("HOST", "localhost"),
port=cool.app.config.get("PORT", 9000)
)
If you're having troubles accessing your Flask server, deployed using PyCharm, take the following into account:
PyCharm doesn't run your main .py file directly, so any code in if __name__ == '__main__': won't be executed, and any changes (like app.run(host='0.0.0.0', port=5000)) won't take effect.
Instead, you should configure the Flask server using Run Configurations, in particular, placing --host 0.0.0.0 --port 5000 into Additional options field.
More about configuring Flask server in PyCharm
You can also set the host (to expose it on a network facing IP address) and port via environment variables.
$ export FLASK_APP=app.py
$ export FLASK_ENV=development
$ export FLASK_RUN_PORT=8000
$ export FLASK_RUN_HOST=0.0.0.0
$ flask run
* Serving Flask app "app.py" (lazy loading)
* Environment: development
* Debug mode: on
* Running on https://0.0.0.0:8000/ (Press CTRL+C to quit)
* Restarting with stat
* Debugger is active!
* Debugger PIN: 329-665-000
See How to get all available Command Options to set environment variables?
Go to your project path on CMD(command Prompt) and execute the following command:-
set FLASK_APP=ABC.py
SET FLASK_ENV=development
flask run -h [yourIP] -p 8080
you will get following o/p on CMD:-
Serving Flask app "expirement.py" (lazy loading)
Environment: development
Debug mode: on
Restarting with stat
Debugger is active!
Debugger PIN: 199-519-700
Running on http://[yourIP]:8080/ (Press CTRL+C to quit)
Now you can access your flask app on another machine using http://[yourIP]:8080/ url
For me i followed the above answer and modified it a bit:
Just grab your ipv4 address using ipconfig on command prompt
Go to the file in which flask code is present
In main function write app.run(host= 'your ipv4 address')
Eg:
Create file .flaskenv in the project root directory.
The parameters in this file are typically:
FLASK_APP=app.py
FLASK_ENV=development
FLASK_RUN_HOST=[dev-host-ip]
FLASK_RUN_PORT=5000
If you have a virtual environment, activate it and do a pip install python-dotenv .
This package is going to use the .flaskenv file, and declarations inside it will be automatically imported across terminal sessions.
Then you can do flask run
This answer is not solely related with flask, but should be applicable for all cannot connect service from another host issue.
use netstat -ano | grep <port> to see if the address is 0.0.0.0 or ::. If it is 127.0.0.1 then it is only for the local requests.
use tcpdump to see if any packet is missing. If it shows obvious imbalance, check routing rules by iptables.
Today I run my flask app as usual, but I noticed it cannot connect from other server. Then I run netstat -ano | grep <port>, and the local address is :: or 0.0.0.0 (I tried both, and I know 127.0.0.1 only allows connection from the local host). Then I used telnet host port, the result is like connect to .... This is very odd. Then I thought I would better check it with tcpdump -i any port <port> -w w.pcap. And I noticed it is all like this:
Then by checking iptables --list OUTPUT section, I could see several rules:
these rules forbid output tcp vital packets in handshaking. By deleting them, the problem is gone.
I had the same problem, I use PyCharm as an editor and when I created the project, PyCharm created a Flask Server. What I did was create a server with Python in the following way;
basically what I did was create a new server but flask if not python
I hope it helps you
This finally worked for me.
import os
Then place this at the end of your python app.py or main file.
if __name__ == "__main__":
port = int(os.environ.get("PORT", 5000))
app.run(host='0.0.0.0', port=port)
go to project path
set FLASK_APP=ABC.py
SET FLASK_ENV=development
flask run -h [yourIP] -p 8080
you will following o/p on CMD:-
* Serving Flask app "expirement.py" (lazy loading)
* Environment: development
* Debug mode: on
* Restarting with stat
* Debugger is active!
* Debugger PIN: 199-519-700
* Running on http://[yourIP]:8080/ (Press CTRL+C to quit)
If none of the above solutions are working, try manually adding "http://" to the beginning of the url.
Chrome can distinguish "[ip-address]:5000" from a search query. But sometimes that works for a while, and then stops connecting, seemingly without me changing anything. My hypothesis is that the browser might sometimes automatically prepend https:// (which it shouldn't, but this fixed it in my case).
In case you need to test your app from an external network.
Simply serve it to the whole Internet with ngrok.com
which will deploy it like a dev server but in no time and locally, saved me a lot of time, and no, I'm not related to that company :)
Just make sure to change the port in your flask app:
app.run(host='0.0.0.0', port=80)

Can someone outside my localhost ping my Flask app when I run it? [duplicate]

I'm not sure if this is Flask specific, but when I run an app in dev mode (http://localhost:5000), I cannot access it from other machines on the network (with http://[dev-host-ip]:5000). With Rails in dev mode, for example, it works fine. I couldn't find any docs regarding the Flask dev server configuration. Any idea what should be configured to enable this?
While this is possible, you should not use the Flask dev server in production. The Flask dev server is not designed to be particularly secure, stable, or efficient. See the docs on deploying for correct solutions.
The --host option to flask run, or the host parameter to app.run(), controls what address the development server listens to. By default it runs on localhost, change it to flask run --host=0.0.0.0 (or app.run(host="0.0.0.0")) to run on all your machine's IP addresses.
0.0.0.0 is a special value that you can't use in the browser directly, you'll need to navigate to the actual IP address of the machine on the network. You may also need to adjust your firewall to allow external access to the port.
The Flask quickstart docs explain this in the "Externally Visible Server" section:
If you run the server you will notice that the server is only
accessible from your own computer, not from any other in the network.
This is the default because in debugging mode a user of the
application can execute arbitrary Python code on your computer.
If you have the debugger disabled or trust the users on your network,
you can make the server publicly available simply by adding
--host=0.0.0.0 to the command line:
$ flask run --host=0.0.0.0
This tells your operating system to listen on all public IPs.
If you use the flask executable to start your server, use flask run --host=0.0.0.0 to change the default from 127.0.0.1 and open it up to non-local connections.
If you run the server you will notice that the server is only
accessible from your own computer, not from any other in the network.
This is the default because in debugging mode a user of the
application can execute arbitrary Python code on your computer.
If you have the debugger disabled or trust the users on your network,
you can make the server publicly available simply by adding
--host=0.0.0.0 to the command line:
$ flask run --host=0.0.0.0
This tells your operating system to listen on all public IPs.
Reference: https://flask.palletsprojects.com/quickstart/
Try this if the 0.0.0.0 method doesn't work
Boring Stuff
I personally battled a lot to get my app accessible to other devices(laptops and mobile phones) through a local-server. I tried the 0.0.0.0 method, but no luck. Then I tried changing the port, but it just didn't work. So, after trying a bunch of different combinations, I arrived to this one, and it solved my problem of deploying my app on a local server.
Steps
Get the local IPv4 address of your computer.
This can be done by typing ipconfig on Windows and ifconfig on Linux
and Mac.
Please note: The above step is to be performed on the machine you are serving the app on, and on not the machine on which you are accessing it. Also note, that the IPv4 address might change if you disconnect and reconnect to the network.
Now, simply run the flask app with the acquired IPv4 address.
flask run -h 192.168.X.X
E.g. In my case (see the image), I ran it as:
flask run -h 192.168.1.100
On my mobile device
Optional Stuff
If you are performing this procedure on Windows and using Power Shell as the CLI, and you still aren't able to access the website, try a CTRL + C command in the shell that's running the app. Power Shell gets frozen up sometimes and it needs a pinch to revive. Doing this might even terminate the server, but it sometimes does the trick.
That's it. Give a thumbs up if you found this helpful.๐Ÿ˜‰
Some more optional stuff
I have created a short Powershell script that will get you your IP address whenever you need one:
$env:getIp = ipconfig
if ($env:getIp -match '(IPv4[\sa-zA-Z.]+:\s[0-9.]+)') {
if ($matches[1] -match '([^a-z\s][\d]+[.\d]+)'){
$ipv4 = $matches[1]
}
}
echo $ipv4
Save it to a file with .ps1 extension (for PowerShell), and run it on before starting your app. You can save it in your project folder and run it as:
.\getIP.ps1; flask run -h $ipv4
Note: I saved the above shellcode in getIP.ps1.
Cool.๐Ÿ‘Œ
Add host='0.0.0.0' to app.run`.
if __name__ == '__main__':
app.run(host='0.0.0.0', port=5000)
If you get OSError: [WinError 10013] An attempt was made to access a socket in a way forbidden by its access permissions on Windows, you either don't have permission to use the port, or something else is using it which you can find with netstat -na|findstr 5000.
Check whether the particular port is open on the server to serve the client or not?
in Ubuntu or Linux distro
sudo ufw enable
sudo ufw allow 5000/tcp //allow the server to handle the request on port 5000
Configure the application to handle remote requests
app.run(host='0.0.0.0' , port=5000)
python3 app.py & #run application in background
If your cool app has it's configuration loaded from an external file, like in the following example, then don't forget to update the corresponding config file with HOST="0.0.0.0"
cool.app.run(
host=cool.app.config.get("HOST", "localhost"),
port=cool.app.config.get("PORT", 9000)
)
If you're having troubles accessing your Flask server, deployed using PyCharm, take the following into account:
PyCharm doesn't run your main .py file directly, so any code in if __name__ == '__main__': won't be executed, and any changes (like app.run(host='0.0.0.0', port=5000)) won't take effect.
Instead, you should configure the Flask server using Run Configurations, in particular, placing --host 0.0.0.0 --port 5000 into Additional options field.
More about configuring Flask server in PyCharm
You can also set the host (to expose it on a network facing IP address) and port via environment variables.
$ export FLASK_APP=app.py
$ export FLASK_ENV=development
$ export FLASK_RUN_PORT=8000
$ export FLASK_RUN_HOST=0.0.0.0
$ flask run
* Serving Flask app "app.py" (lazy loading)
* Environment: development
* Debug mode: on
* Running on https://0.0.0.0:8000/ (Press CTRL+C to quit)
* Restarting with stat
* Debugger is active!
* Debugger PIN: 329-665-000
See How to get all available Command Options to set environment variables?
Go to your project path on CMD(command Prompt) and execute the following command:-
set FLASK_APP=ABC.py
SET FLASK_ENV=development
flask run -h [yourIP] -p 8080
you will get following o/p on CMD:-
Serving Flask app "expirement.py" (lazy loading)
Environment: development
Debug mode: on
Restarting with stat
Debugger is active!
Debugger PIN: 199-519-700
Running on http://[yourIP]:8080/ (Press CTRL+C to quit)
Now you can access your flask app on another machine using http://[yourIP]:8080/ url
For me i followed the above answer and modified it a bit:
Just grab your ipv4 address using ipconfig on command prompt
Go to the file in which flask code is present
In main function write app.run(host= 'your ipv4 address')
Eg:
Create file .flaskenv in the project root directory.
The parameters in this file are typically:
FLASK_APP=app.py
FLASK_ENV=development
FLASK_RUN_HOST=[dev-host-ip]
FLASK_RUN_PORT=5000
If you have a virtual environment, activate it and do a pip install python-dotenv .
This package is going to use the .flaskenv file, and declarations inside it will be automatically imported across terminal sessions.
Then you can do flask run
This answer is not solely related with flask, but should be applicable for all cannot connect service from another host issue.
use netstat -ano | grep <port> to see if the address is 0.0.0.0 or ::. If it is 127.0.0.1 then it is only for the local requests.
use tcpdump to see if any packet is missing. If it shows obvious imbalance, check routing rules by iptables.
Today I run my flask app as usual, but I noticed it cannot connect from other server. Then I run netstat -ano | grep <port>, and the local address is :: or 0.0.0.0 (I tried both, and I know 127.0.0.1 only allows connection from the local host). Then I used telnet host port, the result is like connect to .... This is very odd. Then I thought I would better check it with tcpdump -i any port <port> -w w.pcap. And I noticed it is all like this:
Then by checking iptables --list OUTPUT section, I could see several rules:
these rules forbid output tcp vital packets in handshaking. By deleting them, the problem is gone.
I had the same problem, I use PyCharm as an editor and when I created the project, PyCharm created a Flask Server. What I did was create a server with Python in the following way;
basically what I did was create a new server but flask if not python
I hope it helps you
This finally worked for me.
import os
Then place this at the end of your python app.py or main file.
if __name__ == "__main__":
port = int(os.environ.get("PORT", 5000))
app.run(host='0.0.0.0', port=port)
go to project path
set FLASK_APP=ABC.py
SET FLASK_ENV=development
flask run -h [yourIP] -p 8080
you will following o/p on CMD:-
* Serving Flask app "expirement.py" (lazy loading)
* Environment: development
* Debug mode: on
* Restarting with stat
* Debugger is active!
* Debugger PIN: 199-519-700
* Running on http://[yourIP]:8080/ (Press CTRL+C to quit)
If none of the above solutions are working, try manually adding "http://" to the beginning of the url.
Chrome can distinguish "[ip-address]:5000" from a search query. But sometimes that works for a while, and then stops connecting, seemingly without me changing anything. My hypothesis is that the browser might sometimes automatically prepend https:// (which it shouldn't, but this fixed it in my case).
In case you need to test your app from an external network.
Simply serve it to the whole Internet with ngrok.com
which will deploy it like a dev server but in no time and locally, saved me a lot of time, and no, I'm not related to that company :)
Just make sure to change the port in your flask app:
app.run(host='0.0.0.0', port=80)

docker-compose flask network issue

I have a python flask project which is supposed to be a web app for an internal network. It's in a docker image which is started with a docker-compose file.
Sometimes when I run it, the flask server doesn't get messages from the outside world. I figure it has to be a problem with the docker network that docker-compose automatically creates. Whenever this problem occurs I have to restart the box then bring the container back up, and it fixes itself.
Has anyone else seen this?
When I say it doesn't see connections from outside the box I mean HTTP requests never make it to the flask server. I can attempt to go to the URL corresponding to the flask server from a different machine and the flask server sees nothing. However, if I attempt to send an HTTP GET request from inside the box (not inside the container, but on the box the container is running on) the flask server responds.
So this leads me to believe docker-compose is creating a docker network which isn't configured correctly to allow the container to listen to outside requests.
Here's my docker compose file:
version: '3.7'
services:
falcon:
image: "company.com/internal/falcon:0.1"
container_name: falcon
env_file:
- ~/.env
ports:
- "80:80"
volumes:
- ${REPOS}/falcon:/app
command: /conda/bin/falcon start
This hasn't been tested extensively, but it seems to have solved the problem:
version: '3.7'
services:
falcon:
image: "company.com/internal/falcon:0.1"
container_name: falcon
network_mode: bridge # also tried host, I think bridge is right.
Another solution seemed to omit the network_mode above and put this down below:
networks:
default:
external:
name: prod_default
I still don't know why it happened, but both of these solutions seemed to fix it.

Pycharm debugging manage.py commands in docker compose

I have a pretty simple setup. I'm running Pycharm 2018.2.3 and using docker compose to spin up 3 containers.
My Django application
NGINX to serve static
Postgres DB
I've configured the remote interpreter for debugging the container, and break point work just fine in most cases, at least when I hit my API endpoints or some other action to the django application.
What does not work, is when I run one of my manage custom manage.py custom commands. I've tried this 2 ways so far.
I setup another debug configuration in PyCharm to execute the command. This results in another container spinning up (in place of the original. Running the command, without breaking on any line breaks. Then the whole container shuts down.
I've logged into the container, run the manage.py command directly via the command line, and it execute in the container, but again no breakpoints.
The documentation seems to work in the normal case, but I can't find any help for debugging these commands in the container.
Thanks for any help or tips.
In order to debug Django commands in a Docker Container you can create a new Run/Debug Configuration with following setup:
Use a Python configuration template
Script path: absolut location of manage.py
Parameters: the Django command you want to debug/execute
!important! Python interpreter: Docker Compose interpreter
Just an update in case anybody comes across a similar problem. My personal solution was to not use the manage.py commands, but instead make these same commands available via an http call.
I found that it was easier (and often even more useful) to simply have an endpoint like myserver.com/api/do-admin-function and restrict that to administrative access.
When I put a breakpoint in my code, even running in the container, it breaks just fine as expected and allows me to debug the way I'd like
It can depends on your docker-compose.yml exact content.
See for instance the section "An interactive debugger inside a running container!" of the article "A Simple Recipe for Django Development In Docker (Bonus: Testing with Selenium)" from Adam King.
His docker-compose.yml includes:
version: "2"
services:
django:
container_name: django_server
build:
context: .
dockerfile: Dockerfile
image: docker_tutorial_django
stdin_open: true
tty: true
volumes:
- .:/var/www/myproject
ports:
- "8000:8000"
In it, see:
stdin_open: true
tty: true
[Those 2 lines] are important, because they let us run an interactive terminal.
Hit ctrl-c to kill the server running in your terminal, and then bring it up in the background with docker-compose up -d.
docker ps tells us itโ€™s still running:
We need to attach to that running container, in order to see its server output and pdb breakpoints.
The command docker attach django_server will present you with a blank line, but if you refresh your web browser, youโ€™ll see the server output.
Drop import pdb; pdb.set_trace() in your code and youโ€™ll get the interactive debugger, just like youโ€™re used to.

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