debugging-techniques

# Debugging Techniques

## Purpose

Provides systematic debugging workflows for local, remote, container, and production environments across Python, Go, Rust, and Node.js. Covers interactive debuggers, container debugging with ephemeral containers, and production-safe techniques using correlation IDs and distributed tracing.

## When to Use This Skill

Trigger this skill for:
- Setting breakpoints in Python, Go, Rust, or Node.js code
- Debugging running containers or Kubernetes pods
- Setting up remote debugging connections
- Safely debugging production issues
- Inspecting goroutines, threads, or async tasks
- Analyzing core dumps or stack traces
- Choosing the right debugging tool for a scenario

## Quick Reference by Language

### Python Debugging

**Built-in: pdb**
```python
# Python 3.7+
def buggy_function(x, y):
    breakpoint()  # Stops execution here
    return x / y

# Older Python
import pdb
pdb.set_trace()
```

**Essential pdb commands:**
- `list` (l) - Show code around current line
- `next` (n) - Execute current line, step over functions
- `step` (s) - Execute current line, step into functions
- `continue` (c) - Continue until next breakpoint
- `print var` (p) - Print variable value
- `where` (w) - Show stack trace
- `quit` (q) - Exit debugger

**Enhanced tools:**
- `ipdb` - Enhanced pdb with tab completion, syntax highlighting (`pip install ipdb`)
- `pudb` - Terminal GUI debugger (`pip install pudb`)
- `debugpy` - VS Code integration (included in Python extension)

**Debugging tests:**
```bash
pytest --pdb  # Drop into debugger on test failure
```

For detailed Python debugging patterns, see `references/python-debugging.md`.

### Go Debugging

**Delve - Official Go debugger**

**Installation:**
```bash
go install github.com/go-delve/delve/cmd/dlv@latest
```

**Basic usage:**
```bash
dlv debug main.go              # Debug main package
dlv test github.com/me/pkg     # Debug test suite
dlv attach <pid>               # Attach to running process
dlv debug --