python-steptrace 0.2.0

A lightweight line-by-line Python execution tracer

Steptrace

A lightweight Python execution tracer that records line-by-line execution, call stack, runtime per step, and local/global variables — all filtered to your workspace for clean, readable logs.

Designed for debugging, learning, and understanding program flow.

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Features

• 🔍 Line-by-line execution tracing
• 🧵 Call stack reconstruction
• ⏱ Runtime per step (milliseconds)
• 📦 Local and global variable inspection
• 🚫 Automatically ignores:
  • Built-in modules
  • site-packages
  • Non-workspace files
• 🗂 Auto-incrementing log files (no overwrites)
• 🧼 Safe cleanup of sys.settrace
• 🧩 Supports context manager and decorator usage

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Installation

pip install python-steptrace

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Quick Start

Context Manager (Recommended)

from steptrace import Tracer

def main():
    a = 1
    b = 2
    print(a + b)

with Tracer():
    main()

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Decorator Usage

from steptrace import Tracer

@Tracer().tracer
def main():
    a = 1
    b = 2
    print(a + b)

main()

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Log Output

Logs are written to:

.tracer/tracer.log

or, if a log already exists:

.tracer/tracer_1.log
.tracer/tracer_2.log
...

Example Log Entry

--------------------- Step 3 ---------------------
Runtime: 0.0841 ms
/path/to/file.py::main -- line 8

------> Global variables <------
x: int :: 5

------> Local variables <------
y: int :: 10

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How It Works

The tracer uses Python’s sys.settrace to intercept execution on every line and logs:

• File name
• Function name
• Line number
• Execution time since last step
• Call stack
• Local and global variables

Only files inside your project workspace are traced to keep output relevant.

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Context Manager Behavior

Using the tracer as a context manager ensures:

• Previous trace functions are restored
• Exceptions are not suppressed

with Tracer():
    risky_code()

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When to Use

• Debugging complex logic
• Understanding unfamiliar codebases
• Teaching / learning Python execution flow
• Inspecting variable evolution over time

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Limitations

• Tracing every line may generate large log files
• Not intended for production use
• Performance overhead for long-running programs

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License

MIT License — free to use, modify, and distribute.