exdoc module

This module can be used to automatically generate exceptions documentation marked up in reStructuredText with help from cog and the pexdoc.exh module.

The exceptions to auto-document need to be defined with either the pexdoc.exh.ExHandle.addex() function, the pexdoc.exh.ExHandle.addai() function or via contracts of the pexdoc.pcontracts module, and “traced” before the documentation is generated. In general tracing consists of calling the methods, functions and/or class properties so that all the required exceptions are covered (exceptions raised by contracts are automatically traced when the functions with the contracts are used). A convenient way of tracing a module is to simply run its test suite, provided that it covers the exceptions that need to be documented (for maximum speed the unit tests that cover the exceptions may be segregated so that only these tests need to be executed).

For example, it is desired to auto-document the exceptions of a module my_module.py, which has tests in test_my_module.py. Then a tracing module trace_my_module.py can be created to leverage the already written tests:

# trace_my_module_1.py
# Option 1: use already written test bench
from __future__ import print_function
import copy, os, pytest, pexdoc


def trace_module(no_print=True):
    """Trace my_module exceptions."""
    pwd = os.path.dirname(__file__)
    script_name = os.path.join(pwd, "test_my_module.py")
    with pexdoc.ExDocCxt() as exdoc_obj:
        if pytest.main(["-s", "-vv", "-x", "{0}".format(script_name)]):
            raise RuntimeError("Tracing did not complete successfully")
    if not no_print:
        module_prefix = "docs.support.my_module."
        callable_names = ["func", "MyClass.value"]
        for callable_name in callable_names:
            callable_name = module_prefix + callable_name
            print("\nCallable: {0}".format(callable_name))
            print(exdoc_obj.get_sphinx_doc(callable_name, width=70))
            print("\n")
    return copy.copy(exdoc_obj)


if __name__ == "__main__":
    trace_module(False)

The context manager pexdoc.exdoc.ExDocCxt sets up the tracing environment and returns a pexdoc.exdoc.ExDoc object that can the be used in the documentation string of each callable to extract the exceptions documentation. In this example it is assumed that the tests are written using pytest, but any test framework can be used. Another way to trace the module is to simply call all the functions, methods or class properties that need to be documented. For example:

# trace_my_module_2.py
# Option 2: manually use all callables to document
from __future__ import print_function
import copy, pexdoc, docs.support.my_module


def trace_module(no_print=True):
    """Trace my_module_original exceptions."""
    with pexdoc.ExDocCxt() as exdoc_obj:
        try:
            docs.support.my_module.func("John")
            obj = docs.support.my_module.MyClass()
            obj.value = 5
            obj.value
        except:
            raise RuntimeError("Tracing did not complete successfully")
    if not no_print:
        module_prefix = "docs.support.my_module."
        callable_names = ["func", "MyClass.value"]
        for callable_name in callable_names:
            callable_name = module_prefix + callable_name
            print("\nCallable: {0}".format(callable_name))
            print(exdoc_obj.get_sphinx_doc(callable_name, width=70))
            print("\n")
    return copy.copy(exdoc_obj)


if __name__ == "__main__":
    trace_module(False)

And the actual module my_module code is (before auto-documentation):

"""
Test module.

[[[cog
import os, sys
sys.path.append(os.environ['TRACER_DIR'])
import trace_my_module_1
exobj = trace_my_module_1.trace_module(no_print=True)
]]]
[[[end]]]
"""
# my_module.py

import pexdoc


def func(name):
    r"""
    Print your name.

    :param name: Name to print
    :type  name: string

    .. [[[cog cog.out(exobj.get_sphinx_autodoc(width=69))]]]
    .. [[[end]]]

    """
    # Raise condition evaluated in same call as exception addition
    pexdoc.addex(TypeError, "Argument `name` is not valid", not isinstance(name, str))
    return "My name is {0}".format(name)


class MyClass(object):
    """Store a value."""

    def __init__(self, value=None):  # noqa
        self._value = None if not value else value

    def _get_value(self):
        # Raise condition not evaluated in same call as
        # exception additions
        exobj = pexdoc.addex(RuntimeError, "Attribute `value` not set")
        exobj(not self._value)
        return self._value

    def _set_value(self, value):
        exobj = pexdoc.addex(RuntimeError, "Argument `value` is not valid")
        exobj(not isinstance(value, int))
        self._value = value

    value = property(_get_value, _set_value)
    r"""
    Set or return a value

    :type:  integer
    :rtype: integer or None

    .. [[[cog cog.out(exobj.get_sphinx_autodoc(width=69))]]]
    .. [[[end]]]
    """

A simple shell script can be written to automate the cogging of the my_module.py file:

#!/bin/bash
set -e

finish() {
    export TRACER_DIR=""
    cd ${cpwd}
}
trap finish EXIT

input_file=${1:-my_module.py}
output_file=${2:-my_module.py}
export TRACER_DIR=$(dirname ${input_file})
cog.py -e -x -o ${input_file}.tmp ${input_file} > /dev/null && \
    mv -f ${input_file}.tmp ${input_file}
cog.py -e -o ${input_file}.tmp ${input_file} > /dev/null && \
    mv -f ${input_file}.tmp ${output_file}

After the script is run and the auto-documentation generated, each callable has a reStructuredText marked-up :raises: section:

"""
Test module.

[[[cog
import os, sys
sys.path.append(os.environ['TRACER_DIR'])
import trace_my_module_1
exobj = trace_my_module_1.trace_module(no_print=True)
]]]
[[[end]]]
"""
# my_module_ref.py

import pexdoc


def func(name):
    r"""
    Print your name.

    :param name: Name to print
    :type  name: string

    .. [[[cog cog.out(exobj.get_sphinx_autodoc(width=69))]]]
    .. Auto-generated exceptions documentation for
    .. docs.support.my_module.func

    :raises: TypeError (Argument \`name\` is not valid)

    .. [[[end]]]

    """
    # Raise condition evaluated in same call as exception addition
    pexdoc.addex(TypeError, "Argument `name` is not valid", not isinstance(name, str))
    return "My name is {0}".format(name)


class MyClass(object):
    """Store a value."""

    def __init__(self, value=None):  # noqa
        self._value = None if not value else value

    def _get_value(self):
        # Raise condition not evaluated in same call as
        # exception additions
        exobj = pexdoc.addex(RuntimeError, "Attribute `value` not set")
        exobj(not self._value)
        return self._value

    def _set_value(self, value):
        exobj = pexdoc.addex(RuntimeError, "Argument `value` is not valid")
        exobj(not isinstance(value, int))
        self._value = value

    value = property(_get_value, _set_value)
    r"""
    Set or return a value

    :type:  integer
    :rtype: integer or None

    .. [[[cog cog.out(exobj.get_sphinx_autodoc(width=69))]]]
    .. Auto-generated exceptions documentation for
    .. docs.support.my_module.MyClass.value

    :raises:
     * When assigned

       * RuntimeError (Argument \`value\` is not valid)

     * When retrieved

       * RuntimeError (Attribute \`value\` not set)

    .. [[[end]]]
    """

Warning

Due to the limited introspection capabilities of class properties, only properties defined using the property built-in function can be documented with pexdoc.exdoc.ExDoc.get_sphinx_autodoc(). Properties defined by other methods can still be auto-documented with pexdoc.exdoc.ExDoc.get_sphinx_doc() and explicitly providing the method/function name.

Context managers

class pexdoc.exdoc.ExDocCxt(exclude=None, pickle_fname=None, in_callables_fname=None, out_callables_fname=None)

Bases: object

Context manager to simplify exception tracing.

This manager sets up the tracing environment and returns a pexdoc.ExDoc object that can the be used in the documentation string of each callable to extract the exceptions documentation with either pexdoc.ExDoc.get_sphinx_doc() or pexdoc.ExDoc.get_sphinx_autodoc().

Parameters:
  • exclude (list of strings or None) – Module exclusion list. A particular callable in an otherwise fully qualified name is omitted if it belongs to a module in this list. If None all callables are included
  • pickle_fname (FileName or None) – File name to pickle traced exception handler (useful for debugging purposes). If None all pickle file is created
  • in_callables_fname (FileNameExists or None) – File name that contains traced modules information. File can be produced by either the pexdoc.Callables.save() or pexdoc.exh.ExHandle.save_callables() methods
  • out_callables_fname (FileNameExists or None) – File name to save traced modules information to in JSON format. If the file exists it is overwritten
Raises:
  • OSError (File [in_callables_fname] could not be found)
  • RuntimeError (Argument `in_callables_fname` is not valid)
  • RuntimeError (Argument `exclude` is not valid)
  • RuntimeError (Argument `out_callables_fname` is not valid)
  • RuntimeError (Argument `pickle_fname` is not valid)

For example:

# exdoc_example.py
from pexdoc import contract
@contract(number='int|float', frac_length='int,>=0', rjust=bool)
def peng(number, frac_length, rjust=True):
    return str(number)
>>> from __future__ import print_function
>>> import docs.support.exdoc_example
>>> from pexdoc import ExDocCxt
>>> with ExDocCxt() as exdoc_obj:
...     value = docs.support.exdoc_example.peng(1e6, 3, False)
>>> print(exdoc_obj.get_sphinx_doc('docs.support.exdoc_example.peng'))
.. Auto-generated exceptions documentation for
.. docs.support.exdoc_example.peng
<BLANKLINE>
:raises:
 * RuntimeError (Argument \`frac_length\` is not valid)
<BLANKLINE>
 * RuntimeError (Argument \`number\` is not valid)
<BLANKLINE>
 * RuntimeError (Argument \`rjust\` is not valid)
<BLANKLINE>
<BLANKLINE>

Classes

class pexdoc.exdoc.ExDoc(exh_obj, depth=None, exclude=None)

Bases: object

Generate exception documentation with reStructuredText mark-up.

Parameters:
  • exh_obj (pexdoc.exh.ExHandle) – Exception handler containing exception information for the callable(s) to be documented
  • depth (non-negative integer or None) – Default hierarchy levels to include in the exceptions per callable (see pexdoc.ExDoc.depth). If None exceptions at all depths are included
  • exclude (list of strings or None) – Default list of (potentially partial) module and callable names to exclude from exceptions per callable (see pexdoc.ExDoc.exclude). If None all callables are included
Return type:

pexdoc.ExDoc

Raises:
  • RuntimeError (Argument `depth` is not valid)
  • RuntimeError (Argument `exclude` is not valid)
  • RuntimeError (Argument `exh_obj` is not valid)
  • RuntimeError (Exceptions database is empty)
  • RuntimeError (Exceptions do not have a common callable)
  • ValueError (Object of argument `exh_obj` does not have any exception trace information)
get_sphinx_autodoc(depth=None, exclude=None, width=72, error=False, raised=False, no_comment=False)

Return exception list in reStructuredText auto-determining callable name.

Parameters:
  • depth (non-negative integer or None) – Hierarchy levels to include in the exceptions list (overrides default depth argument; see pexdoc.ExDoc.depth). If None exceptions at all depths are included
  • exclude (list of strings or None) – List of (potentially partial) module and callable names to exclude from exceptions list (overrides default exclude argument, see pexdoc.ExDoc.exclude). If None all callables are included
  • width (integer) – Maximum width of the lines of text (minimum 40)
  • error (boolean) – Flag that indicates whether an exception should be raised if the callable is not found in the callables exceptions database (True) or not (False)
  • raised (boolean) – Flag that indicates whether only exceptions that were raised (and presumably caught) should be documented (True) or all registered exceptions should be documented (False)
  • no_comment (boolean) – Flag that indicates whether a reStructuredText comment labeling the callable (method, function or class property) should be printed (False) or not (True) before the exceptions documentation
Raises:
  • RuntimeError (Argument `depth` is not valid)
  • RuntimeError (Argument `error` is not valid)
  • RuntimeError (Argument `exclude` is not valid)
  • RuntimeError (Argument `no_comment` is not valid)
  • RuntimeError (Argument `raised` is not valid)
  • RuntimeError (Argument `width` is not valid)
  • RuntimeError (Callable not found in exception list: [name])
  • RuntimeError (Unable to determine callable name)
get_sphinx_doc(name, depth=None, exclude=None, width=72, error=False, raised=False, no_comment=False)

Return an exception list marked up in reStructuredText.

Parameters:
  • name (string) – Name of the callable (method, function or class property) to generate exceptions documentation for
  • depth (non-negative integer or None) – Hierarchy levels to include in the exceptions list (overrides default depth argument; see pexdoc.ExDoc.depth). If None exceptions at all depths are included
  • exclude (list of strings or None) – List of (potentially partial) module and callable names to exclude from exceptions list (overrides default exclude argument; see pexdoc.ExDoc.exclude). If None all callables are included
  • width (integer) – Maximum width of the lines of text (minimum 40)
  • error (boolean) – Flag that indicates whether an exception should be raised if the callable is not found in the callables exceptions database (True) or not (False)
  • raised (boolean) – Flag that indicates whether only exceptions that were raised (and presumably caught) should be documented (True) or all registered exceptions should be documented (False)
  • no_comment (boolean) – Flag that indicates whether a reStructuredText comment labeling the callable (method, function or class property) should be printed (False) or not (True) before the exceptions documentation
Raises:
  • RuntimeError (Argument `depth` is not valid)
  • RuntimeError (Argument `error` is not valid)
  • RuntimeError (Argument `exclude` is not valid)
  • RuntimeError (Argument `no_comment` is not valid)
  • RuntimeError (Argument `raised` is not valid)
  • RuntimeError (Argument `width` is not valid)
  • RuntimeError (Callable not found in exception list: [name])
depth

Get or set the default hierarchy levels to include in the exceptions per callable.

For example, a function my_func() calls two other functions, get_data() and process_data(), and in turn get_data() calls another function, open_socket(). In this scenario, the calls hierarchy is:

my_func            <- depth = 0
├get_data          <- depth = 1
│└open_socket      <- depth = 2
└process_data      <- depth = 1

Setting depth=0 means that only exceptions raised by my_func() are going to be included in the documentation; Setting depth=1 means that only exceptions raised by my_func(), get_data() and process_data() are going to be included in the documentation; and finally setting depth=2 (in this case it has the same effects as depth=None) means that only exceptions raised by my_func(), get_data(), process_data() and open_socket() are going to be included in the documentation.

Return type:non-negative integer
Raises:RuntimeError (Argument `depth` is not valid)
exclude

Get or set default list of (potentially partial) module and callable names to exclude from exceptions per callable.

For example, ['firstmod.ex'] excludes all exceptions from modules firstmod.exh and firstmod.exdoc (it acts as r'firstmod.ex*'). In addition to these modules, ['firstmod.ex', 'secmod.peng'] excludes exceptions from the function secmod.peng.

Return type:list
Raises:RuntimeError (Argument `exclude` is not valid)