mirror of https://github.com/python/cpython
135 lines
4.4 KiB
ReStructuredText
135 lines
4.4 KiB
ReStructuredText
:mod:`trace` --- Trace or track Python statement execution
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==========================================================
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.. module:: trace
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:synopsis: Trace or track Python statement execution.
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The :mod:`trace` module allows you to trace program execution, generate
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annotated statement coverage listings, print caller/callee relationships and
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list functions executed during a program run. It can be used in another program
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or from the command line.
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.. seealso::
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Latest version of the :source:`trace module Python source code
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<Lib/trace.py>`
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.. _trace-cli:
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Command Line Usage
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------------------
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The :mod:`trace` module can be invoked from the command line. It can be as
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simple as ::
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python -m trace --count somefile.py ...
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The above will generate annotated listings of all Python modules imported during
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the execution of :file:`somefile.py`.
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The following command-line arguments are supported:
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:option:`--trace`, :option:`-t`
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Display lines as they are executed.
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:option:`--count`, :option:`-c`
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Produce a set of annotated listing files upon program completion that shows how
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many times each statement was executed.
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:option:`--report`, :option:`-r`
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Produce an annotated list from an earlier program run that used the
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:option:`--count` and :option:`--file` arguments.
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:option:`--no-report`, :option:`-R`
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Do not generate annotated listings. This is useful if you intend to make
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several runs with :option:`--count` then produce a single set of annotated
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listings at the end.
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:option:`--listfuncs`, :option:`-l`
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List the functions executed by running the program.
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:option:`--trackcalls`, :option:`-T`
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Generate calling relationships exposed by running the program.
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:option:`--file`, :option:`-f`
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Name a file containing (or to contain) counts.
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:option:`--coverdir`, :option:`-C`
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Name a directory in which to save annotated listing files.
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:option:`--missing`, :option:`-m`
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When generating annotated listings, mark lines which were not executed with
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'``>>>>>>``'.
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:option:`--summary`, :option:`-s`
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When using :option:`--count` or :option:`--report`, write a brief summary to
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stdout for each file processed.
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:option:`--ignore-module`
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Accepts comma separated list of module names. Ignore each of the named
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module and its submodules (if it is a package). May be given
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multiple times.
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:option:`--ignore-dir`
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Ignore all modules and packages in the named directory and subdirectories
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(multiple directories can be joined by os.pathsep). May be given multiple
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times.
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.. _trace-api:
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Programming Interface
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---------------------
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.. class:: Trace(count=1, trace=1, countfuncs=0, countcallers=0, ignoremods=(), ignoredirs=(), infile=None, outfile=None, timing=False)
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Create an object to trace execution of a single statement or expression. All
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parameters are optional. *count* enables counting of line numbers. *trace*
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enables line execution tracing. *countfuncs* enables listing of the functions
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called during the run. *countcallers* enables call relationship tracking.
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*ignoremods* is a list of modules or packages to ignore. *ignoredirs* is a list
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of directories whose modules or packages should be ignored. *infile* is the
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file from which to read stored count information. *outfile* is a file in which
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to write updated count information. *timing* enables a timestamp relative
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to when tracing was started to be displayed.
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.. method:: Trace.run(cmd)
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Run *cmd* under control of the Trace object with the current tracing parameters.
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.. method:: Trace.runctx(cmd, globals=None, locals=None)
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Run *cmd* under control of the Trace object with the current tracing parameters
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in the defined global and local environments. If not defined, *globals* and
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*locals* default to empty dictionaries.
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.. method:: Trace.runfunc(func, *args, **kwds)
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Call *func* with the given arguments under control of the :class:`Trace` object
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with the current tracing parameters.
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This is a simple example showing the use of this module::
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import sys
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import trace
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# create a Trace object, telling it what to ignore, and whether to
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# do tracing or line-counting or both.
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tracer = trace.Trace(
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ignoredirs=[sys.prefix, sys.exec_prefix],
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trace=0,
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count=1)
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# run the new command using the given tracer
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tracer.run('main()')
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# make a report, placing output in /tmp
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r = tracer.results()
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r.write_results(show_missing=True, coverdir="/tmp")
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