interrogate: explain yourself

Interrogate a codebase for docstring coverage.

Why Do I Need This?

interrogate checks your code base for missing docstrings.

Documentation should be as important as code itself. And it should live within code. Python standardized docstrings, allowing for developers to navigate libraries as simply as calling help() on objects, and with powerful tools like Sphinx, pydoc, and Docutils to automatically generate HTML, LaTeX, PDFs, etc.

Enter: interrogate.

interrogate will tell you which methods, functions, classes, and modules have docstrings, and which do not. Use interrogate to:

• Get an understanding of how well your code is documented;
• Add it to CI/CD checks to enforce documentation on newly-added code;
• Assess a new code base for (one aspect of) code quality and maintainability.

Let's get started.

Requirements

interrogate supports Python 3.6 and above.

Installation

interrogate is available on PyPI and GitHub. The recommended installation method is pip-installing into a virtualenv:

$ pip install interrogate

Extras

interrogate provides a way to generate a shields.io-like coverage badge as an SVG file. To generate a PNG file instead, install interrogate with the extras [png]:

$ pip install interrogate[png]

NOTICE: Additional system libraries/tools may be required in order to generate a PNG file of the coverage badge:

• on Windows, install Visual C++ compiler for Cairo;
• on macOS, install cairo and libffi (with Homebrew for example);
• on Linux, install the cairo, python3-dev and libffi-dev packages (names may vary depending on distribution).

Refer to the cairosvg documentation for more information.

Usage

Try it out on a Python project:

$ interrogate [PATH]
RESULT: PASSED (minimum: 80.0%, actual: 100.0%)

Add verbosity to see a summary:

$ interrogate -v [PATH]

================== Coverage for /Users/lynn/dev/interrogate/ ====================
------------------------------------ Summary ------------------------------------
| Name                                  |   Total |   Miss |   Cover |   Cover% |
|---------------------------------------|---------|--------|---------|----------|
| src/interrogate/__init__.py           |       1 |      0 |       1 |     100% |
| src/interrogate/__main__.py           |       1 |      0 |       1 |     100% |
| src/interrogate/badge_gen.py          |       6 |      0 |       6 |     100% |
| src/interrogate/cli.py                |       2 |      0 |       2 |     100% |
| src/interrogate/config.py             |       8 |      0 |       8 |     100% |
| src/interrogate/coverage.py           |      27 |      0 |      27 |     100% |
| src/interrogate/utils.py              |      10 |      0 |      10 |     100% |
| src/interrogate/visit.py              |      18 |      0 |      18 |     100% |
| tests/functional/__init__.py          |       1 |      0 |       1 |     100% |
| tests/functional/test_cli.py          |       8 |      0 |       8 |     100% |
| tests/functional/test_coverage.py     |      10 |      0 |      10 |     100% |
| tests/unit/__init__.py                |       1 |      0 |       1 |     100% |
| tests/unit/test_badge_gen.py          |       8 |      0 |       8 |     100% |
| tests/unit/test_config.py             |      10 |      0 |      10 |     100% |
| tests/unit/test_utils.py              |      13 |      0 |      13 |     100% |
|---------------------------------------|---------|--------|---------|----------|
| TOTAL                                 |     124 |      0 |     124 |   100.0% |
---------------- RESULT: PASSED (minimum: 80.0%, actual: 100.0%) ----------------

Add even more verbosity:

$ interrogate -vv [PATH]

================== Coverage for /Users/lynn/dev/interrogate/ ====================
------------------------------- Detailed Coverage -------------------------------
| Name                                                                |  Status |
|---------------------------------------------------------------------|---------|
| src/interrogate/__init__.py (module)                                | COVERED |
|---------------------------------------------------------------------|---------|
| src/interrogate/__main__.py (module)                                | COVERED |
|---------------------------------------------------------------------|---------|
| src/interrogate/badge_gen.py (module)                               | COVERED |
|   save_badge (L42)                                                  | COVERED |
|   get_badge (L87)                                                   | COVERED |
|   should_generate_badge (L103)                                      | COVERED |
|   get_color (L160)                                                  | COVERED |
|   create (L173)                                                     | COVERED |
|---------------------------------------------------------------------|---------|
| src/interrogate/cli.py (module)                                     | COVERED |
|   main (L258)                                                       | COVERED |
|---------------------------------------------------------------------|---------|
| src/interrogate/config.py (module)                                  | COVERED |
|   InterrogateConfig (L19)                                           | COVERED |
|   find_project_root (L61)                                           | COVERED |
|   find_project_config (L89)                                         | COVERED |
|   parse_pyproject_toml (L100)                                       | COVERED |
|   sanitize_list_values (L116)                                       | COVERED |
|   parse_setup_cfg (L139)                                            | COVERED |
|   read_config_file (L173)                                           | COVERED |
|---------------------------------------------------------------------|---------|
| src/interrogate/coverage.py (module)                                | COVERED |
|   BaseInterrogateResult (L23)                                       | COVERED |
|     BaseInterrogateResult.perc_covered (L37)                        | COVERED |
|   InterrogateFileResult (L54)                                       | COVERED |
|     InterrogateFileResult.combine (L67)                             | COVERED |
|   InterrogateResults (L81)                                          | COVERED |
|     InterrogateResults.combine (L93)                                | COVERED |
|   InterrogateCoverage (L101)                                        | COVERED |
|     InterrogateCoverage._add_common_exclude (L121)                  | COVERED |
|     InterrogateCoverage._filter_files (L128)                        | COVERED |
|     InterrogateCoverage.get_filenames_from_paths (L141)             | COVERED |
|     InterrogateCoverage._filter_nodes (L168)                        | COVERED |
|     InterrogateCoverage._filter_inner_nested (L194)                 | COVERED |
|     InterrogateCoverage._get_file_coverage (L203)                   | COVERED |
|     InterrogateCoverage._get_coverage (L231)                        | COVERED |
|     InterrogateCoverage.get_coverage (L248)                         | COVERED |
|     InterrogateCoverage._get_filename (L253)                        | COVERED |
|     InterrogateCoverage._get_detailed_row (L264)                    | COVERED |
|     InterrogateCoverage._create_detailed_table (L281)               | COVERED |
|       InterrogateCoverage._create_detailed_table._sort_nodes (L288) | COVERED |
|     InterrogateCoverage._print_detailed_table (L315)                | COVERED |
|     InterrogateCoverage._create_summary_table (L338)                | COVERED |
|     InterrogateCoverage._print_summary_table (L381)                 | COVERED |
|     InterrogateCoverage._sort_results (L399)                        | COVERED |
|     InterrogateCoverage._get_header_base (L429)                     | COVERED |
|     InterrogateCoverage._print_omitted_file_count (L438)            | COVERED |
|     InterrogateCoverage.print_results (L469)                        | COVERED |
|---------------------------------------------------------------------|---------|
| src/interrogate/utils.py (module)                                   | COVERED |
|   parse_regex (L21)                                                 | COVERED |
|   smart_open (L40)                                                  | COVERED |
|   get_common_base (L60)                                             | COVERED |
|   OutputFormatter (L80)                                             | COVERED |
|     OutputFormatter.should_markup (L90)                             | COVERED |
|     OutputFormatter.set_detailed_markup (L105)                      | COVERED |
|     OutputFormatter.set_summary_markup (L129)                       | COVERED |
|     OutputFormatter._interrogate_line_formatter (L158)              | COVERED |
|     OutputFormatter.get_table_formatter (L226)                      | COVERED |
|---------------------------------------------------------------------|---------|
| src/interrogate/visit.py (module)                                   | COVERED |
|   CovNode (L15)                                                     | COVERED |
|   CoverageVisitor (L44)                                             | COVERED |
|     CoverageVisitor._has_doc (L58)                                  | COVERED |
|     CoverageVisitor._visit_helper (L65)                             | COVERED |
|     CoverageVisitor._is_nested_func (L112)                          | COVERED |
|     CoverageVisitor._is_nested_cls (L121)                           | COVERED |
|     CoverageVisitor._is_private (L133)                              | COVERED |
|     CoverageVisitor._is_semiprivate (L141)                          | COVERED |
|     CoverageVisitor._is_ignored_common (L151)                       | COVERED |
|     CoverageVisitor._has_property_decorators (L168)                 | COVERED |
|     CoverageVisitor._has_setters (L182)                             | COVERED |
|     CoverageVisitor._is_func_ignored (L193)                         | COVERED |
|     CoverageVisitor._is_class_ignored (L217)                        | COVERED |
|     CoverageVisitor.visit_Module (L221)                             | COVERED |
|     CoverageVisitor.visit_ClassDef (L228)                           | COVERED |
|     CoverageVisitor.visit_FunctionDef (L237)                        | COVERED |
|     CoverageVisitor.visit_AsyncFunctionDef (L246)                   | COVERED |
|---------------------------------------------------------------------|---------|
| tests/functional/__init__.py (module)                               | COVERED |
|---------------------------------------------------------------------|---------|
| tests/functional/test_cli.py (module)                               | COVERED |
|   runner (L22)                                                      | COVERED |
|   test_run_no_paths (L30)                                           | COVERED |
|   test_run_shortflags (L77)                                         | COVERED |
|   test_run_longflags (L106)                                         | COVERED |
|   test_run_multiple_flags (L124)                                    | COVERED |
|   test_generate_badge (L135)                                        | COVERED |
|   test_incompatible_options (L170)                                  | COVERED |
|---------------------------------------------------------------------|---------|
| tests/functional/test_coverage.py (module)                          | COVERED |
|   test_coverage_simple (L60)                                        | COVERED |
|   test_coverage_errors (L73)                                        | COVERED |
|   test_print_results (L101)                                         | COVERED |
|   test_print_results_omit_covered (L130)                            | COVERED |
|   test_print_results_omit_none (L156)                               | COVERED |
|   test_print_results_omit_all_summary (L174)                        | COVERED |
|   test_print_results_omit_all_detailed (L198)                       | COVERED |
|   test_print_results_ignore_module (L226)                           | COVERED |
|   test_print_results_single_file (L253)                             | COVERED |
|---------------------------------------------------------------------|---------|
| tests/unit/__init__.py (module)                                     | COVERED |
|---------------------------------------------------------------------|---------|
| tests/unit/test_badge_gen.py (module)                               | COVERED |
|   test_save_badge (L26)                                             | COVERED |
|   test_save_badge_windows (L50)                                     | COVERED |
|   test_save_badge_no_cairo (L62)                                    | COVERED |
|   test_get_badge (L73)                                              | COVERED |
|   test_should_generate (L96)                                        | COVERED |
|   test_get_color (L115)                                             | COVERED |
|   test_create (L136)                                                | COVERED |
|---------------------------------------------------------------------|---------|
| tests/unit/test_config.py (module)                                  | COVERED |
|   test_find_project_root (L29)                                      | COVERED |
|   test_find_project_config (L48)                                    | COVERED |
|   test_parse_pyproject_toml (L57)                                   | COVERED |
|   test_sanitize_list_values (L93)                                   | COVERED |
|   test_parse_setup_cfg (L98)                                        | COVERED |
|   test_parse_setup_cfg_raises (L123)                                | COVERED |
|   test_read_config_file_none (L134)                                 | COVERED |
|   test_read_config_file (L193)                                      | COVERED |
|   test_read_config_file_raises (L207)                               | COVERED |
|---------------------------------------------------------------------|---------|
| tests/unit/test_utils.py (module)                                   | COVERED |
|   test_parse_regex (L32)                                            | COVERED |
|   test_smart_open (L39)                                             | COVERED |
|   test_get_common_base (L69)                                        | COVERED |
|   test_get_common_base_windows (L100)                               | COVERED |
|   test_output_formatter_should_markup (L132)                        | COVERED |
|   test_output_formatter_set_detailed_markup (L163)                  | COVERED |
|   test_output_formatter_set_summary_markup (L206)                   | COVERED |
|   test_output_formatter_interrogate_line_formatter (L258)           | COVERED |
|   test_output_formatter_interrogate_line_formatter_windows (L319)   | COVERED |
|   test_output_formatter_get_table_formatter (L343)                  | COVERED |
|   test_output_formatter_get_table_formatter_py38 (L381)             | COVERED |
|   test_output_formatter_get_table_formatter_raises (L395)           | COVERED |
|---------------------------------------------------------------------|---------|

------------------------------------ Summary ------------------------------------
| Name                                  |   Total |   Miss |   Cover |   Cover% |
|---------------------------------------|---------|--------|---------|----------|
| src/interrogate/__init__.py           |       1 |      0 |       1 |     100% |
| src/interrogate/__main__.py           |       1 |      0 |       1 |     100% |
| src/interrogate/badge_gen.py          |       6 |      0 |       6 |     100% |
| src/interrogate/cli.py                |       2 |      0 |       2 |     100% |
| src/interrogate/config.py             |       8 |      0 |       8 |     100% |
| src/interrogate/coverage.py           |      27 |      0 |      27 |     100% |
| src/interrogate/utils.py              |      10 |      0 |      10 |     100% |
| src/interrogate/visit.py              |      18 |      0 |      18 |     100% |
| tests/functional/__init__.py          |       1 |      0 |       1 |     100% |
| tests/functional/test_cli.py          |       8 |      0 |       8 |     100% |
| tests/functional/test_coverage.py     |      10 |      0 |      10 |     100% |
| tests/unit/__init__.py                |       1 |      0 |       1 |     100% |
| tests/unit/test_badge_gen.py          |       8 |      0 |       8 |     100% |
| tests/unit/test_config.py             |      10 |      0 |      10 |     100% |
| tests/unit/test_utils.py              |      13 |      0 |      13 |     100% |
|---------------------------------------|---------|--------|---------|----------|
| TOTAL                                 |     124 |      0 |     124 |   100.0% |
---------------- RESULT: PASSED (minimum: 80.0%, actual: 100.0%) ----------------

Other Usage

Generate a shields.io badge (like this one! ):

$ interrogate --generate-badge PATH
RESULT: PASSED (minimum: 80.0%, actual: 100.0%)
Generated badge to /Users/lynn/dev/interrogate/docs/_static/interrogate_badge.svg

See below for more badge configuration.

Add it to your tox.ini file to enforce a level of coverage:

[testenv:doc]
deps = interrogate
skip_install = true
commands =
    interrogate --quiet --fail-under 95 src tests

Or use it with pre-commit:

repos:
  - repo: https://github.com/econchick/interrogate
    rev: 1.5.0  # or master if you're bold
    hooks:
      - id: interrogate
        args: [--quiet, --fail-under=95]

Use it within your code directly:

>>> from interrogate import coverage
>>> cov = coverage.InterrogateCoverage(paths=["src"])
>>> results = cov.get_coverage()
>>> results
InterrogateResults(total=68, covered=65, missing=3)

Use interrogate with GitHub Actions. Check out the action written & maintained by Jack McKew (thank you, Jack!).

Configuration

Configure within your pyproject.toml (interrogate will automatically detect a pyproject.toml file and pick up default values for the command line options):

$ interrogate -c pyproject.toml [OPTIONS] [PATHS]...

[tool.interrogate]
ignore-init-method = true
ignore-init-module = false
ignore-magic = false
ignore-semiprivate = false
ignore-private = false
ignore-property-decorators = false
ignore-module = false
ignore-nested-functions = false
ignore-nested-classes = true
ignore-setters = false
fail-under = 95
exclude = ["setup.py", "docs", "build"]
ignore-regex = ["^get$", "^mock_.*", ".*BaseClass.*"]
# possible values: 0 (minimal output), 1 (-v), 2 (-vv)
verbose = 0
quiet = false
whitelist-regex = []
color = true
omit-covered-files = false
generate-badge = "."
badge-format = "svg"

Or configure within your setup.cfg (interrogate will automatically detect a setup.cfg file and pick up default values for the command line options):

$ interrogate -c setup.cfg [OPTIONS] [PATHS]...

[tool:interrogate]
ignore-init-method = true
ignore-init-module = false
ignore-magic = false
ignore-semiprivate = false
ignore-private = false
ignore-property-decorators = false
ignore-module = false
ignore-nested-functions = false
ignore-nested-classes = true
ignore-setters = false
fail-under = 95
exclude = setup.py,docs,build
ignore-regex = ^get$,^mock_.*,.*BaseClass.*
; possible values: 0 (minimal output), 1 (-v), 2 (-vv)
verbose = 0
quiet = false
whitelist-regex =
color = true
omit-covered-files = false
generate-badge = .
badge-format = svg

Warning

The use of setup.cfg is not recommended unless for very simple use cases. .cfg files use a different parser than pyproject.toml which might cause hard to track down problems. When possible, it is recommended to use pyproject.toml to define your interrogate configuration.

Badge Options

Badge Format

The default file format is svg. Use the --badge-format flag to create a png file instead. Note: interrogate must be installed with interrogate[png] in order to generate png files (see above).

$ interrogate --generate-badge PATH --badge-format png
RESULT: PASSED (minimum: 80.0%, actual: 100.0%)
Generated badge to /Users/lynn/dev/interrogate/docs/_static/interrogate_badge.png

Badge Style

The following badge styles are available via the --badge-style flag:

option	example
flat
flat-square
flat-square-modified (default)
for-the-badge
plastic
social

Command Line Options

To view all options available, run interrogate --help:

interrogate -h
Usage: interrogate [OPTIONS] [PATHS]...

  Measure and report on documentation coverage in Python modules.

Options:
  --version                       Show the version and exit.
  -v, --verbose                   Level of verbosity.

                                  NOTE: When configuring verbosity in
                                  pyproject.toml or setup.cfg, `verbose=1`
                                  maps to `-v`, and `verbose=2` maps to `-vv`.
                                  `verbose=0` is the equivalent of no verbose
                                  flags used, producing minimal output.
  -q, --quiet                     Do not print output  [default: False]
  -f, --fail-under INT | FLOAT    Fail when coverage % is less than a given
                                  amount.  [default: 80.0]

  -e, --exclude PATH              Exclude PATHs of files and/or directories.
                                  Multiple `-e/--exclude` invocations
                                  supported.

  -i, --ignore-init-method        Ignore `__init__` method of classes.
                                  [default: False]

  -I, --ignore-init-module        Ignore `__init__.py` modules.  [default:
                                  False]

  -m, --ignore-magic              Ignore all magic methods of classes.
                                  [default: False]

                                  NOTE: This does not include the `__init__`
                                  method. To ignore `__init__` methods, use
                                  `--ignore-init-method`.

  -M, --ignore-module             Ignore module-level docstrings.  [default:
                                  False]

  -n, --ignore-nested-functions   Ignore nested functions and methods.
                                  [default: False]

  -C, --ignore-nested-classes     Ignore nested classes.  [default: False]

  -p, --ignore-private            Ignore private classes, methods, and
                                  functions starting with two underscores.
                                  [default: False]

                                  NOTE: This does not include magic methods;
                                  use `--ignore-magic` and/or `--ignore-init-
                                  method` instead.

  -P, --ignore-property-decorators
                                  Ignore methods with property setter/getter
                                  decorators.  [default: False]

  -S, --ignore-setters            Ignore methods with property setter
                                  decorators.  [default: False]

  -s, --ignore-semiprivate        Ignore semiprivate classes, methods, and
                                  functions starting with a single underscore.
                                  [default: False]

  -r, --ignore-regex STR          Regex identifying class, method, and
                                  function names to ignore. Multiple
                                  `-r/--ignore-regex` invocations supported.

  -w, --whitelist-regex STR       Regex identifying class, method, and
                                  function names to include. Multiple
                                  `-w/--whitelist-regex` invocations
                                  supported.

  -o, --output FILE               Write output to a given FILE.  [default:
                                  stdout]

  --color / --no-color            Toggle color output on/off when printing to
                                  stdout.  [default: True]

  --omit-covered-files            Omit reporting files that have 100%
                                  documentation coverage. This option is
                                  ignored if verbosity is not set.  [default:
                                  False]

  -g, --generate-badge PATH       Generate a 'shields.io' status badge (an SVG
                                  image) in at a given file or directory. Will
                                  not generate a badge if results did not
                                  change from an existing badge of the same
                                  path.

  --badge-format [svg|png]        File format for the generated badge. Used
                                  with the `-g/--generate-badge` flag.
                                  [default: svg]

                                  NOTE: To generate a PNG file, interrogate
                                  must be installed with `interrogate[png]`,
                                  i.e. `pip install interrogate[png]`.

  --badge-style [flat|flat-square|flat-square-modified|for-the-badge|plastic|social]
                                  Desired style of shields.io badge. Used with
                                  the `-g/--generate-badge` flag. [default:
                                  flat-square-modified]

  -h, --help                      Show this message and exit.
  -c, --config FILE               Read configuration from `pyproject.toml` or
                                  `setup.cfg`.

Users of Interrogate

• attrs
• OpenMMLab's ecosystem
• pyjanitor
• klio

Interrogate in the Wild

• Why You Should Document Your Tests by Hynek Schlawack
• Episode #181: It's time to interrogate your Python code - PythonBytes podcast

Credits

interrogate was inspired by docstr-coverage, which was forked from Alexey "DataGreed" Strelkov's docstring-coverage, which was inspired by a 2004 recipe from James Harlow (turtles...).

The cute logo is by JustineW purchased via the Noun Project (but also available under the Creative Commons License with attribution).