# Debugging Python CLI Applications: A Pro Tip #protip #dbt #python #cli Navigating any Python CLI app during runtime can help while debugging. Here's a quick guide on how to attach a debugger to a Python CLI application, using `dbt` (Data Build Tool) as an example. ## Running Dbt with Python Instead of using the dbt command directly, you can invoke it through Python: First figure out the module path by typing: ```bash cat $(which dbt) # you will see following .. import re import sys from dbt.cli.main import cli ... ``` `dbt.cli.main` is the module path. Then you can run: ```bash python -m dbt.cli.main seed ``` Once you're able to run dbt via Python, attaching a debugger becomes straightforward. For example, to use the Python debugger (pdb), you can start your command like this: ```bash python -m pdb -m dbt.cli.main seed ``` This approach allows you to get detailed tracebacks in case of errors. For instance: With the debugger attached, you can step through the code execution. ```python File "/usr/local/lib/python3.8/site-packages/dbt/cli/main.py", line 761, in seed results = task.run() File "/usr/local/lib/python3.8/site-packages/dbt/task/runnable.py", line 454, in run self._runtime_initialize() File "/usr/local/lib/python3.8/site-packages/dbt/task/compile.py", line 147, in _runtime_initialize super()._runtime_initialize() File "/usr/local/lib/python3.8/site-packages/dbt/task/runnable.py", line 143, in _runtime_initialize File "/usr/local/lib/python3.8/site-packages/dbt/task/base.py", line 173, in compile_manifest self.graph = compiler.compile(self.manifest) File "/usr/local/lib/python3.8/site-packages/dbt/compilation.py", line 453, in compile self.initialize() File "/usr/local/lib/python3.8/site-packages/dbt/compilation.py", line 284, in initialize make_directory(self.config.packages_install_path) File "/usr/local/lib/python3.8/functools.py", line 875, in wrapper return dispatch(args[0].__class__)(*args, **kw) File "/usr/local/lib/python3.8/site-packages/dbt/clients/system.py", line ``` Use breakpoints to pause execution at key points and s to step into functions. This method offers a granular view of the program's flow, making it easier to identify and fix issues. ## Conclusion By running your Python CLI app through the Python interpreter and attaching a debugger, you gain a powerful tool for navigating and debugging your code in real-time. This technique is invaluable for developers looking to streamline their debugging process and enhance code quality.