"compileall" — Byte-compile Python libraries
********************************************

**Source code:** Lib/compileall.py

======================================================================

This module provides some utility functions to support installing
Python libraries.  These functions compile Python source files in a
directory tree. This module can be used to create the cached byte-code
files at library installation time, which makes them available for use
even by users who don’t have write permission to the library
directories.


Command-line use
================

This module can work as a script (using **python -m compileall**) to
compile Python sources.

directory ...
file ...

   Positional arguments are files to compile or directories that
   contain source files, traversed recursively.  If no argument is
   given, behave as if the command line was "-l <directories from
   sys.path>".

-l

   Do not recurse into subdirectories, only compile source code files
   directly contained in the named or implied directories.

-f

   Force rebuild even if timestamps are up-to-date.

-q

   Do not print the list of files compiled. If passed once, error
   messages will still be printed. If passed twice ("-qq"), all output
   is suppressed.

-d destdir

   Directory prepended to the path to each file being compiled.  This
   will appear in compilation time tracebacks, and is also compiled in
   to the byte-code file, where it will be used in tracebacks and
   other messages in cases where the source file does not exist at the
   time the byte-code file is executed.

-x regex

   regex is used to search the full path to each file considered for
   compilation, and if the regex produces a match, the file is
   skipped.

-i list

   Read the file "list" and add each line that it contains to the list
   of files and directories to compile.  If "list" is "-", read lines
   from "stdin".

-b

   Write the byte-code files to their legacy locations and names,
   which may overwrite byte-code files created by another version of
   Python.  The default is to write files to their **PEP 3147**
   locations and names, which allows byte-code files from multiple
   versions of Python to coexist.

-r

   Control the maximum recursion level for subdirectories. If this is
   given, then "-l" option will not be taken into account. **python -m
   compileall <directory> -r 0** is equivalent to **python -m
   compileall <directory> -l**.

-j N

   Use *N* workers to compile the files within the given directory. If
   "0" is used, then the result of "os.cpu_count()" will be used.

--invalidation-mode [timestamp|checked-hash|unchecked-hash]

   Control how the generated byte-code files are invalidated at
   runtime. The "timestamp" value, means that ".pyc" files with the
   source timestamp and size embedded will be generated. The "checked-
   hash" and "unchecked-hash" values cause hash-based pycs to be
   generated. Hash-based pycs embed a hash of the source file contents
   rather than a timestamp. See Cached bytecode invalidation for more
   information on how Python validates bytecode cache files at
   runtime. The default is "timestamp" if the "SOURCE_DATE_EPOCH"
   environment variable is not set, and "checked-hash" if the
   "SOURCE_DATE_EPOCH" environment variable is set.

Changed in version 3.2: Added the "-i", "-b" and "-h" options.

Changed in version 3.5: Added the  "-j", "-r", and "-qq" options.
"-q" option was changed to a multilevel value.  "-b" will always
produce a byte-code file ending in ".pyc", never ".pyo".

Changed in version 3.7: Added the "--invalidation-mode" option.

There is no command-line option to control the optimization level used
by the "compile()" function, because the Python interpreter itself
already provides the option: **python -O -m compileall**.

Similarly, the "compile()" function respects the "sys.pycache_prefix"
setting. The generated bytecode cache will only be useful if
"compile()" is run with the same "sys.pycache_prefix" (if any) that
will be used at runtime.


Public functions
================

compileall.compile_dir(dir, maxlevels=10, ddir=None, force=False, rx=None, quiet=0, legacy=False, optimize=-1, workers=1, invalidation_mode=None)

   Recursively descend the directory tree named by *dir*, compiling
   all ".py" files along the way. Return a true value if all the files
   compiled successfully, and a false value otherwise.

   The *maxlevels* parameter is used to limit the depth of the
   recursion; it defaults to "10".

   If *ddir* is given, it is prepended to the path to each file being
   compiled for use in compilation time tracebacks, and is also
   compiled in to the byte-code file, where it will be used in
   tracebacks and other messages in cases where the source file does
   not exist at the time the byte-code file is executed.

   If *force* is true, modules are re-compiled even if the timestamps
   are up to date.

   If *rx* is given, its search method is called on the complete path
   to each file considered for compilation, and if it returns a true
   value, the file is skipped.

   If *quiet* is "False" or "0" (the default), the filenames and other
   information are printed to standard out. Set to "1", only errors
   are printed. Set to "2", all output is suppressed.

   If *legacy* is true, byte-code files are written to their legacy
   locations and names, which may overwrite byte-code files created by
   another version of Python.  The default is to write files to their
   **PEP 3147** locations and names, which allows byte-code files from
   multiple versions of Python to coexist.

   *optimize* specifies the optimization level for the compiler.  It
   is passed to the built-in "compile()" function.

   The argument *workers* specifies how many workers are used to
   compile files in parallel. The default is to not use multiple
   workers. If the platform can’t use multiple workers and *workers*
   argument is given, then sequential compilation will be used as a
   fallback.  If *workers* is 0, the number of cores in the system is
   used.  If *workers* is lower than "0", a "ValueError" will be
   raised.

   *invalidation_mode* should be a member of the
   "py_compile.PycInvalidationMode" enum and controls how the
   generated pycs are invalidated at runtime.

   Changed in version 3.2: Added the *legacy* and *optimize*
   parameter.

   Changed in version 3.5: Added the *workers* parameter.

   Changed in version 3.5: *quiet* parameter was changed to a
   multilevel value.

   Changed in version 3.5: The *legacy* parameter only writes out
   ".pyc" files, not ".pyo" files no matter what the value of
   *optimize* is.

   Changed in version 3.6: Accepts a *path-like object*.

   Changed in version 3.7: The *invalidation_mode* parameter was
   added.

   Changed in version 3.7.2: The *invalidation_mode* parameter’s
   default value is updated to None.

   Changed in version 3.8: Setting *workers* to 0 now chooses the
   optimal number of cores.

compileall.compile_file(fullname, ddir=None, force=False, rx=None, quiet=0, legacy=False, optimize=-1, invalidation_mode=None)

   Compile the file with path *fullname*. Return a true value if the
   file compiled successfully, and a false value otherwise.

   If *ddir* is given, it is prepended to the path to the file being
   compiled for use in compilation time tracebacks, and is also
   compiled in to the byte-code file, where it will be used in
   tracebacks and other messages in cases where the source file does
   not exist at the time the byte-code file is executed.

   If *rx* is given, its search method is passed the full path name to
   the file being compiled, and if it returns a true value, the file
   is not compiled and "True" is returned.

   If *quiet* is "False" or "0" (the default), the filenames and other
   information are printed to standard out. Set to "1", only errors
   are printed. Set to "2", all output is suppressed.

   If *legacy* is true, byte-code files are written to their legacy
   locations and names, which may overwrite byte-code files created by
   another version of Python.  The default is to write files to their
   **PEP 3147** locations and names, which allows byte-code files from
   multiple versions of Python to coexist.

   *optimize* specifies the optimization level for the compiler.  It
   is passed to the built-in "compile()" function.

   *invalidation_mode* should be a member of the
   "py_compile.PycInvalidationMode" enum and controls how the
   generated pycs are invalidated at runtime.

   New in version 3.2.

   Changed in version 3.5: *quiet* parameter was changed to a
   multilevel value.

   Changed in version 3.5: The *legacy* parameter only writes out
   ".pyc" files, not ".pyo" files no matter what the value of
   *optimize* is.

   Changed in version 3.7: The *invalidation_mode* parameter was
   added.

   Changed in version 3.7.2: The *invalidation_mode* parameter’s
   default value is updated to None.

compileall.compile_path(skip_curdir=True, maxlevels=0, force=False, quiet=0, legacy=False, optimize=-1, invalidation_mode=None)

   Byte-compile all the ".py" files found along "sys.path". Return a
   true value if all the files compiled successfully, and a false
   value otherwise.

   If *skip_curdir* is true (the default), the current directory is
   not included in the search.  All other parameters are passed to the
   "compile_dir()" function.  Note that unlike the other compile
   functions, "maxlevels" defaults to "0".

   Changed in version 3.2: Added the *legacy* and *optimize*
   parameter.

   Changed in version 3.5: *quiet* parameter was changed to a
   multilevel value.

   Changed in version 3.5: The *legacy* parameter only writes out
   ".pyc" files, not ".pyo" files no matter what the value of
   *optimize* is.

   Changed in version 3.7: The *invalidation_mode* parameter was
   added.

   Changed in version 3.7.2: The *invalidation_mode* parameter’s
   default value is updated to None.

To force a recompile of all the ".py" files in the "Lib/" subdirectory
and all its subdirectories:

   import compileall

   compileall.compile_dir('Lib/', force=True)

   # Perform same compilation, excluding files in .svn directories.
   import re
   compileall.compile_dir('Lib/', rx=re.compile(r'[/\\][.]svn'), force=True)

   # pathlib.Path objects can also be used.
   import pathlib
   compileall.compile_dir(pathlib.Path('Lib/'), force=True)

See also:

  Module "py_compile"
     Byte-compile a single source file.
