27.6. trace — 跟踪或追踪 Python 语句的执行 ¶

27.6.1. 命令行用法 ¶

trace module can be invoked from the command line. It can be as simple as

python -m trace --count -C . somefile.py ...
								

The above will execute somefile.py and generate annotated listings of all Python modules imported during the execution into the current directory.

--help ¶

Display usage and exit.

--version ¶

Display the version of the module and exit.

27.6.2. Programmatic Interface ¶

class trace. Trace ( count=1 , trace=1 , countfuncs=0 , countcallers=0 , ignoremods=() , ignoredirs=() , infile=None , outfile=None , timing=False ) ¶

Create an object to trace execution of a single statement or expression. All parameters are optional. count enables counting of line numbers. trace enables line execution tracing. countfuncs enables listing of the functions called during the run. countcallers enables call relationship tracking. ignoremods is a list of modules or packages to ignore. ignoredirs is a list of directories whose modules or packages should be ignored. infile is the name of the file from which to read stored count information. outfile is the name of the file in which to write updated count information. timing enables a timestamp relative to when tracing was started to be displayed.

run ( cmd ) ¶

Execute the command and gather statistics from the execution with the current tracing parameters. cmd must be a string or code object, suitable for passing into exec() .

runctx ( cmd , globals=None , locals=None ) ¶

Execute the command and gather statistics from the execution with the current tracing parameters, in the defined global and local environments. If not defined, globals and locals default to empty dictionaries.

runfunc ( func , *args , **kwds ) ¶

调用 func with the given arguments under control of the Trace object with the current tracing parameters.

结果 ( ) ¶

返回 CoverageResults object that contains the cumulative results of all previous calls to run , runctx and runfunc for the given Trace instance. Does not reset the accumulated trace results.

class trace. CoverageResults ¶

A container for coverage results, created by Trace.results() . Should not be created directly by the user.

update ( other ) ¶

Merge in data from another CoverageResults 对象。

write_results ( show_missing=True , summary=False , coverdir=None ) ¶

Write coverage results. Set show_missing to show lines that had no hits. Set summary to include in the output the coverage summary per module. coverdir specifies the directory into which the coverage result files will be output. If None , the results for each source file are placed in its directory.

A simple example demonstrating the use of the programmatic interface:

import sys
import trace
# create a Trace object, telling it what to ignore, and whether to
# do tracing or line-counting or both.
tracer = trace.Trace(
    ignoredirs=[sys.prefix, sys.exec_prefix],
    trace=0,
    count=1)
# run the new command using the given tracer
tracer.run('main()')
# make a report, placing output in the current directory
r = tracer.results()
r.write_results(show_missing=True, coverdir=".")