python-execution-trace

Trace the local context of a Python function's execution. You can step through any function's execution, viewing the values of all local variables at every step.

All this by just adding a decorator to your function!

How to

Install the lib:

pip install execution-trace

Annotate the function you want to trace.

from execution_trace.record import record


@record()
def foo(x, y):
    a = x + y
    return a

You can also record multiple executions of the function, by passing in a parameter:

@record(42)

Run your code as you normally would. You'll get a message such as:

INFO:execution_trace.record:Will record execution of foo in /tmp/record_a0nQs5.json . Use `view_trace /tmp/record_a0nQs5.json` to view it.

View the trace using the supplied viewer:

view_trace /tmp/record_a0nQs5.json

Go to http://127.0.0.1:5000/.

Viewer

Use the up/down arrow keys or the vertical scroll to step through the program's execution. Change between function executions using the number input on the right.

Supported syntax

Hopefully everything:

• assignments/expressions
• if/elif/else
• while/else
• for/else
• try/except/else
• return
• recursive functions

See execution_trace/tests/functions/.

Performance

No need to worry about performance - the instrumentation overhead is present only for the number of executions that you want recorded. Once the data was gathered, only the original version of your code is run.

Caveats

Can only trace a function at a time.

No work was done to support multithreading at this point.