Python Trace Module
The trace module allows you to trace program execution, generate annotated statement coverage listings, print caller/callee relationships and list functions executed during a program run. It can be used in another program or from the command line.
Importing the Module
import traceCommand Line Usage
The trace module can be invoked from the command line. It can be quite useful for debugging or understanding code flow without modifying the source.
Tracing Execution
To trace the execution of a script:
python -m trace --trace myscript.pyCoverage Analysis
To generate a coverage report (annotated listing of source files):
python -m trace --count --coverdir=. myscript.pyThis will create a .cover file for each module imported and executed.
Programmatic Usage
You can also use the trace module within your Python code using the Trace class.
Creating a Tracer
import trace
# Create a Trace object
tracer = trace.Trace(
count=False,
trace=True,
timing=True
)
# Run a command string
tracer.run('print("Hello World")')Tracing Functions
You can trace specific functions using runfunc().
import trace
def recurse(level):
print(f"Recurse level {level}")
if level > 0:
recurse(level - 1)
tracer = trace.Trace(trace=True)
tracer.runfunc(recurse, 2)