1 :mod:`trace` --- Trace or track Python statement execution 2 ========================================================== 3 4 .. module:: trace 5 :synopsis: Trace or track Python statement execution. 6 7 **Source code:** :source:`Lib/trace.py` 8 9 -------------- 10 11 The :mod:`trace` module allows you to trace program execution, generate 12 annotated statement coverage listings, print caller/callee relationships and 13 list functions executed during a program run. It can be used in another program 14 or from the command line. 15 16 .. _trace-cli: 17 18 Command-Line Usage 19 ------------------ 20 21 The :mod:`trace` module can be invoked from the command line. It can be as 22 simple as :: 23 24 python -m trace --count -C . somefile.py ... 25 26 The above will execute :file:`somefile.py` and generate annotated listings of 27 all Python modules imported during the execution into the current directory. 28 29 .. program:: trace 30 31 .. cmdoption:: --help 32 33 Display usage and exit. 34 35 .. cmdoption:: --version 36 37 Display the version of the module and exit. 38 39 Main options 40 ^^^^^^^^^^^^ 41 42 At least one of the following options must be specified when invoking 43 :mod:`trace`. The :option:`--listfuncs <-l>` option is mutually exclusive with 44 the :option:`--trace <-t>` and :option:`--count <-c>` options. When 45 :option:`--listfuncs <-l>` is provided, neither :option:`--count <-c>` nor 46 :option:`--trace <-t>` are accepted, and vice versa. 47 48 .. program:: trace 49 50 .. cmdoption:: -c, --count 51 52 Produce a set of annotated listing files upon program completion that shows 53 how many times each statement was executed. See also 54 :option:`--coverdir <-C>`, :option:`--file <-f>` and 55 :option:`--no-report <-R>` below. 56 57 .. cmdoption:: -t, --trace 58 59 Display lines as they are executed. 60 61 .. cmdoption:: -l, --listfuncs 62 63 Display the functions executed by running the program. 64 65 .. cmdoption:: -r, --report 66 67 Produce an annotated list from an earlier program run that used the 68 :option:`--count <-c>` and :option:`--file <-f>` option. This does not 69 execute any code. 70 71 .. cmdoption:: -T, --trackcalls 72 73 Display the calling relationships exposed by running the program. 74 75 Modifiers 76 ^^^^^^^^^ 77 78 .. program:: trace 79 80 .. cmdoption:: -f, --file=<file> 81 82 Name of a file to accumulate counts over several tracing runs. Should be 83 used with the :option:`--count <-c>` option. 84 85 .. cmdoption:: -C, --coverdir=<dir> 86 87 Directory where the report files go. The coverage report for 88 ``package.module`` is written to file :file:`{dir}/{package}/{module}.cover`. 89 90 .. cmdoption:: -m, --missing 91 92 When generating annotated listings, mark lines which were not executed with 93 ``>>>>>>``. 94 95 .. cmdoption:: -s, --summary 96 97 When using :option:`--count <-c>` or :option:`--report <-r>`, write a brief 98 summary to stdout for each file processed. 99 100 .. cmdoption:: -R, --no-report 101 102 Do not generate annotated listings. This is useful if you intend to make 103 several runs with :option:`--count <-c>`, and then produce a single set of 104 annotated listings at the end. 105 106 .. cmdoption:: -g, --timing 107 108 Prefix each line with the time since the program started. Only used while 109 tracing. 110 111 Filters 112 ^^^^^^^ 113 114 These options may be repeated multiple times. 115 116 .. program:: trace 117 118 .. cmdoption:: --ignore-module=<mod> 119 120 Ignore each of the given module names and its submodules (if it is a 121 package). The argument can be a list of names separated by a comma. 122 123 .. cmdoption:: --ignore-dir=<dir> 124 125 Ignore all modules and packages in the named directory and subdirectories. 126 The argument can be a list of directories separated by :data:`os.pathsep`. 127 128 .. _trace-api: 129 130 Programmatic Interface 131 ---------------------- 132 133 .. class:: Trace([count=1[, trace=1[, countfuncs=0[, countcallers=0[, ignoremods=()[, ignoredirs=()[, infile=None[, outfile=None[, timing=False]]]]]]]]]) 134 135 Create an object to trace execution of a single statement or expression. All 136 parameters are optional. *count* enables counting of line numbers. *trace* 137 enables line execution tracing. *countfuncs* enables listing of the 138 functions called during the run. *countcallers* enables call relationship 139 tracking. *ignoremods* is a list of modules or packages to ignore. 140 *ignoredirs* is a list of directories whose modules or packages should be 141 ignored. *infile* is the name of the file from which to read stored count 142 information. *outfile* is the name of the file in which to write updated 143 count information. *timing* enables a timestamp relative to when tracing was 144 started to be displayed. 145 146 .. method:: run(cmd) 147 148 Execute the command and gather statistics from the execution with 149 the current tracing parameters. *cmd* must be a string or code object, 150 suitable for passing into :func:`exec`. 151 152 .. method:: runctx(cmd, globals=None, locals=None) 153 154 Execute the command and gather statistics from the execution with the 155 current tracing parameters, in the defined global and local 156 environments. If not defined, *globals* and *locals* default to empty 157 dictionaries. 158 159 .. method:: runfunc(func, *args, **kwds) 160 161 Call *func* with the given arguments under control of the :class:`Trace` 162 object with the current tracing parameters. 163 164 .. method:: results() 165 166 Return a :class:`CoverageResults` object that contains the cumulative 167 results of all previous calls to ``run``, ``runctx`` and ``runfunc`` 168 for the given :class:`Trace` instance. Does not reset the accumulated 169 trace results. 170 171 .. class:: CoverageResults 172 173 A container for coverage results, created by :meth:`Trace.results`. Should 174 not be created directly by the user. 175 176 .. method:: update(other) 177 178 Merge in data from another :class:`CoverageResults` object. 179 180 .. method:: write_results([show_missing=True[, summary=False[, coverdir=None]]]) 181 182 Write coverage results. Set *show_missing* to show lines that had no 183 hits. Set *summary* to include in the output the coverage summary per 184 module. *coverdir* specifies the directory into which the coverage 185 result files will be output. If ``None``, the results for each source 186 file are placed in its directory. 187 188 A simple example demonstrating the use of the programmatic interface:: 189 190 import sys 191 import trace 192 193 # create a Trace object, telling it what to ignore, and whether to 194 # do tracing or line-counting or both. 195 tracer = trace.Trace( 196 ignoredirs=[sys.prefix, sys.exec_prefix], 197 trace=0, 198 count=1) 199 200 # run the new command using the given tracer 201 tracer.run('main()') 202 203 # make a report, placing output in the current directory 204 r = tracer.results() 205 r.write_results(show_missing=True, coverdir=".") 206 207
