How to run/debug a streamlit application from an IDE - debugging

Question

I really like streamlit as an environment for research. Mixing a notebook/dashboard-like output I can design quickly with pure code for its definition (no cells etc.) as well as the ability to influence my code through widgets while it runs is a game changer.
For this purpose, I was looking for a way to run or even debug a streamlit application, since the tutorials only show it being started via the commandline:
streamlit run code.py
Is there a way to do either running or debugging from an IDE?

Answer 1

I found a way to at least run the code from the IDE (PyCharm in my case). The streamlit run code.py command can directly be called from your IDE. (The streamlit run code.py command actually calls python -m streamlit.cli run code.py, which was the former solution to run from the IDE.)
The -m streamlit run goes into the interpreter options field of the Run/Debug Configuration (this is supported by Streamlit, so has guarantees to not be broken in the future1), the code.py goes into the Script path field as expected. In past versions, it was also working to use -m streamlit.cli run in the interpreter options field of the Run/Debug Configuration, but this option might break in the future.
Unfortunately, debugging that way does not seem to work since the parameters appended by PyCharm are passed to streamlit instead of the pydev debugger.
Edit: Just found a way to debug your own scripts. Instead of debugging your script, you debug the streamlit.cli module which runs your script. To do so, you need to change from Script path: to Module name: in the top-most field (there is a slightly hidden dropdown box there...). Then you can insert streamlit.cli into the field. As the parameters, you now add run code.py into the Parameters: field of the Run/Debug Configuration.
EDIT: adding #sismo 's comment
If your script needs to be run with some args you can easily add them as
run main.py -- --option1 val1 --option2 val2
Note the first -- with blank: it is needed to stop streamlit argument parsing and pass to main.py argument parsing.
1 https://discuss.streamlit.io/t/run-streamlit-from-pycharm/21624/3

Answer 2

If you're a VS Code user, you can debug your Streamlit app by adding the following configuration to your launch.json file:
{
"name": "Python:Streamlit",
"type": "python",
"request": "launch",
"module": "streamlit",
"args": [
"run",
"${file}",
"--server.port",
"SPECIFY_YOUR_OWN_PORT_NUMBER_HERE" ]
}
Specifying the port number allows you to launch the app on a fixed port number each time you run your debug script.
Once you've updated your launch.json file, you need to navigate to the Run tab on the left gutter of the VS code app and tell it which Python config it should use to debug the app:
Selecting Debug config for python interpreter
Thanks to git-steb for pointing me to the solution!

Answer 3

I've come up with an alternative solution which allows you to use PyCharm debugging in a natural way. Simply set up a run script (which I call run.py which looks like this:
from streamlit import bootstrap
real_script = 'main_script.py'
bootstrap.run(real_script, f'run.py {real_script}', [], {})
and set that up as a normal Python run configuration in PyCharm.

Answer 4

Cannot comment so I have to put this as an answer.
An addition to #Ben's answer (module debugging part):
if your script needs to be run with some args you can easily add them as
run main.py -- --option1 val1 --option2 val2
Note the first -- with blank: it is needed to stop streamlit argument parsing and pass to main.py argument parsing

Answer 5

With some modification to #aiwa answer - This worked for me in the VS code version - 1.58
{
"configurations": [
{
"name": "Python:Streamlit",
"type": "python",
"request": "launch",
"module": "streamlit.cli",
"args": [
"run",
"${file}"
],
}
]
}

Answer 6

Aug, 12, 2022:
Please update your pip and streamlit versions. Sometime, it is mandatory to update all both version.
pip install pip --upgrade
pip install --upgrade streamlit
Open Pycharm Editor and go to the Edit Configuration file as mentioned below in picture. Do not clear streamlit in my dropdown box. Click on dropdown box.
Run/Debug Configurations:
You have to change three directories remember that script path.
1) You can obtain script path by typing which streamlit in terminal and paste the path in script path.
2) click on working directory and give directory of your python file which contain streamlit.
3) in Paramaters: give python file name like app.py with run.

Answer 7

Alongside other solutions, another easy and quick solution is using pdb library.
For instance;
st.dataframe(df)
import pdb; pdb.set_trace()
st.bar_chart(df)
When you run code, your IDE (or even command line) will stop at the 'set trace' point and the command line show you something like that:
(Pdb)>
In that case, you can call your variables and process them on the command line. For instance:
For other options of PDB library please see: https://docs.python.org/3/library/pdb.html