gulp-flake8

Flake8 plugin for gulp.

Flake8 is a python tool that glues together pep8, pyflakes, mccabe, and third-party plugins to check the style and quality of some python code. This plugin wraps the flake8 binary for gulp and provides fancy and original reporters.

Install

npm install @petervanderdoes/gulp-flake8 --save-dev

This plugin requires flake8 to be installed.

From a terminal:

python -m pip install flake8

Usage

gulp.task('lint-python', function () {
  return gulp.src(['**/*py',
    '!**/build/**',
    '!**/dist/**',
    '!**/node_modules/**'])
    .pipe(flake8())
    .pipe(flake8.reporter())
    .pipe(flake8.failOnError());
});

Important

You need to include/exclude files and directories through the gulp.src option. Due to the way this plugin and flake8 works, it won't respect the exclude option in the flake8 configuration.

API

flake8(configFile)

configFile

Type: String

You can pass the path to your flake8 config file directly to the plugin, though if your config file uses the standard file name and location then flake8 will find it by default.

gulp.src('**/*py')
  .pipe(flake8('.flake8'))

flake8(options)

options

Type: Object

For example:

scsslint({
  config: '.flake8',
  bin: 'flake8',
  args: ['--ignore=W503'] // see caveat below
})

options property: config

Type: String

Path to your flake8 config file. Default is undefined.

options property: bin

Type: String

The flake8 call signature. Default is flake8.

options property: args

Type: Array

An array of additional arguments supported by flake8. See flake8 --help for options.

For example:

args: ['--ignore=W503']

N.B.: Flake8 works best using a configuration file. This is just an personal observation.

flake8.reporter(format)

format

Type: String

The format of the report. The plugin comes with two build-in options:

• original
• fancy

Default is original

original

The same format like flake8

Example:

stuff
  .pipe(flake8())
  .pipe(flake8.reporter())

Example Output:

./__main__.py 17:1: F401 'os' imported but unused
./sample/config/apps.py 25:9: F401 'sample.config.signals' imported but unused
./sample/config/urls.py 26:4: E121 continuation line under-indented for hanging indent
./sample/config/urls.py 34:4: E121 continuation line under-indented for hanging indent
./sample/config/urls.py 44:4: E121 continuation line under-indented for hanging indent
./sample/core/apps.py 25:9: F401 'sample.core.signals' imported but unused

fancy

A colored output and if a file has multiple errors, the filename is only displayed on the first error.

Example:

stuff
  .pipe(flake8())
  .pipe(flake8.reporter('fancy'))

Example output:

__main__.py 17:1 F401 'os' imported but unused
sample/config/apps.py 25:9 F401 'sample.config.signals' imported but unused
sample/config/urls.py 26:4 E121 continuation line under-indented for hanging indent
                      34:4 E121 continuation line under-indented for hanging indent
                      44:4 E121 continuation line under-indented for hanging indent
sample/core/apps.py 25:9 F401 'sample.core.signals' imported but unused

flake8.failOnError()

Stop a task/stream if a flake8 error has been reported for any file.

gulp.task('lint-python', function () {
  return gulp.src('**/*py')
    .pipe(flake8())
    .pipe(flake8.failOnError());
});

Result

Type: Object

The following properties are set to the result object:

  result.flake8.success = true; // or false
  result.flake8.errorCount = 0; // number of errors returned by Flake8
  result.flake8.errorList = []; // Flake8 errors

The objects in errorList all have the following properties

result.flake8.errorList = [{
  'filename': 'full path of the filename',
  'row': 10,
  'column': 4,
  'reason': 'a description of the error'
}]

Custom Reporters

Custom reporter functions can be passed as flake8.reporter(reporterFunc). The reporter function will be called for each linted file that includes an error or warning and will be passed the result object as described above.

var flake8 = require('@petervanderdoes/gulp-flake8');
var gulp = require('gulp');
var gulpUtil = require('gulp-util');

var myReporter = function(file) {
  gulpUtil.log(result.flake8.errorCount + ' errors');
};

gulp.task('lint', function() {
  return gulp.src('*.py')
    .pipe(flake8())
    .pipe(flake8.reporter(myReporter));
});

See src/reports.js for more detailed examples.

This plugin was inspired by the following gulp plugins:

• gulp-scsslint
• gulp-eslint