Debugging your code in Python - Examples

These examples show how to perform debugging on your python applications. They are part of the medium blog Debugging your code in Python - pdb vs. rpdb.

The blog goes uses these examples to explain using the python debugger(pdb) and the remote python debugger(rpdb).

Running the Application

Here I'll point to how to run the application. There are a few prerequisites needed for the Flask webserver (used for testing rpdb).

Prerequisites

1. Make sure you are using python3

$ python --version
Python 3.9.6

2. Setup a virtual environment

$ virtualenv venv
created virtual environment ...

$ source venv/bin/activate
(venv) ➜ $PWD

3. Install Requirements

$ pip install -r requirements.txt

Collecting flask ...

pdb

In order to test out pdb, we simply run the following:

$ python pdb/main.py

Enter some words: I am a cat

> /Users/fernandodiaz/Desktop/debugging/pdb/main.py(23)<module>()
-> num_chars = count(input)
(Pdb)

Now in the (Pdb) view we can run the commands as seen in the blog.

rpdb

In order to test out rpdb, we simply run the following:

$ python rpdb/run.py

* Serving Flask app 'remote' (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: on
 * Running on all addresses.
   WARNING: This is a development server. Do not use it in a production deployment.
 * Running on http://192.168.1.147:5000/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 926-264-267

NOTE: Make sure it python is run while inside the virtual environment.

A popup may come up, make sure to allow the connection:

then we open a separate terminal to send a request:

$ curl -X POST http://192.168.1.147:5000/ -d '{"message": "This is a message"}'

# It should freeze

then go back to the terminal running the web-server and verify that it is connected to the debugger:

...
pdb is running on 127.0.0.1:4444

Now let's open another terminal to run rpdb:

$ nc 127.0.0.1 4444

> /Users/fernandodiaz/Desktop/debugging/rpdb/remote/routes.py(15)add_note()
-> if not msg:
(Pdb)

Now in the (Pdb) view we can run the commands as seen in the blog.