Adapt "black" code formatter

this includes pre-commit hooks, and a linter step on Jenkins

Author: beniwohli

.flake8

@@ -1,4 +1,4 @@
 [flake8]
 exclude=elasticapm/utils/wrapt,build,src,tests,dist,conftest.py,setup.py
 max-line-length=120
-ignore=E731
+ignore=E731,W503,E203

.pre-commit-config.yaml

@@ -0,0 +1,20 @@
+repos:
+# seed-isort-config disabled for now, see https://github.com/asottile/seed-isort-config/issues/10
+#-   repo: https://github.com/asottile/seed-isort-config
+#    rev: v1.1.0
+#    hooks:
+#    -   id: seed-isort-config
+-   repo: https://github.com/pre-commit/mirrors-isort
+    rev: v4.3.4
+    hooks:
+    -   id: isort
+-   repo: https://github.com/ambv/black
+    rev: stable
+    hooks:
+    - id: black
+      language_version: python3
+-   repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v1.3.0
+    hooks:
+    -   id: flake8
+        exclude: elasticapm\/utils\/wrapt|build|src|tests|dist|conftest.py|setup.py

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 [Check the diff](https://github.com/elastic/apm-agent-python/compare/v2.2.1...master)
 
+ - adapted "black" code formatter for this repository (#262)
  - **BREAKING**: dropped support for Python 3.3 (#242) 
  - **BREAKING**: changed order of precedence when evaluating configuration (#255, #261)
  - **BREAKING**: changed default value of `span_frames_min_duration` setting 

CONTRIBUTING.md

@@ -33,12 +33,23 @@ Once your changes are ready to submit for review:
     We ask this of all contributors in order to assure our users of the origin and continuing existence of the code.
     You only need to sign the CLA once.
 
-2. Test your changes
+1. Code style
+
+    This project uses several tools to maintain a consistent code style:
+    
+     * the automatic code formatter [black](https://black.readthedocs.io/en/stable/)
+     * sorting of imports via [isort](https://isort.readthedocs.io/en/latest/)
+     * [flake8](http://flake8.pycqa.org/en/latest/)
+     
+    The easiest way to make sure your pull request adheres to the the code style
+    is to install [pre-commit](https://pre-commit.com/).
+
+1. Test your changes
 
     Run the test suite to make sure that nothing is broken.
     See [testing](#testing) for details.
 
-3. Rebase your changes
+1. Rebase your changes
 
     Update your local repository with the most recent code from the main repo,
     and rebase your branch on top of the latest master branch.
@@ -49,7 +60,7 @@ Once your changes are ready to submit for review:
     This makes them easier to review.
     As a final step before merging we will either ask you to squash all commits yourself or we'll do it for you.
 
-4. Submit a pull request
+1. Submit a pull request
 
     Push your local changes to your forked copy of the repository and [submit a pull request](https://help.github.com/articles/using-pull-requests).
     In the pull request,
@@ -58,7 +69,7 @@ Once your changes are ready to submit for review:
     Also mention the number of the issue where discussion has taken place,
     eg "Closes #123".
 
-5. Be patient
+1. Be patient
 
     We might not be able to review your code as fast as we would like to,
     but we'll do our best to dedicate it the attention it deserves.

conftest.py

@@ -2,9 +2,15 @@
 import sys
 from os.path import abspath, dirname, join
 
-from tests.fixtures import (elasticapm_client, instrument, not_so_random,
-                            sending_elasticapm_client, validating_httpserver,
-                            waiting_httpserver, waiting_httpsserver)
+from tests.fixtures import (
+    elasticapm_client,
+    instrument,
+    not_so_random,
+    sending_elasticapm_client,
+    validating_httpserver,
+    waiting_httpserver,
+    waiting_httpsserver,
+)
 from tests.utils.compat import middleware_setting
 
 try:
@@ -19,17 +25,17 @@
 
 where_am_i = dirname(abspath(__file__))
 
-BASE_TEMPLATE_DIR = join(where_am_i, 'tests', 'contrib', 'django', 'testapp',
-                         'templates')
+BASE_TEMPLATE_DIR = join(where_am_i, "tests", "contrib", "django", "testapp", "templates")
 
 sys.path.insert(0, where_am_i)
 
 # don't run tests of dependencies that land in "build" and "src"
-collect_ignore = ['build', 'src']
+collect_ignore = ["build", "src"]
 
 
 try:
     from psycopg2cffi import compat
+
     compat.register()
 except ImportError:
     pass
@@ -42,32 +48,29 @@ def pytest_configure(config):
         settings = None
     if settings is not None and not settings.configured:
         import django
+
         settings_dict = dict(
-            SECRET_KEY='42',
+            SECRET_KEY="42",
             DATABASES={
-                'default': {
-                    'ENGINE': 'django.db.backends.sqlite3',
-                    'NAME': 'elasticapm_tests.db',
-                    'TEST_NAME': 'elasticapm_tests.db',
-                    'TEST': {
-                        'NAME': 'elasticapm_tests.db',
-                    }
-                },
+                "default": {
+                    "ENGINE": "django.db.backends.sqlite3",
+                    "NAME": "elasticapm_tests.db",
+                    "TEST_NAME": "elasticapm_tests.db",
+                    "TEST": {"NAME": "elasticapm_tests.db"},
+                }
             },
-            TEST_DATABASE_NAME='elasticapm_tests.db',
+            TEST_DATABASE_NAME="elasticapm_tests.db",
             INSTALLED_APPS=[
-                'django.contrib.auth',
-                'django.contrib.admin',
-                'django.contrib.sessions',
-                'django.contrib.sites',
-                'django.contrib.redirects',
-
-                'django.contrib.contenttypes',
-
-                'elasticapm.contrib.django',
-                'tests.contrib.django.testapp',
+                "django.contrib.auth",
+                "django.contrib.admin",
+                "django.contrib.sessions",
+                "django.contrib.sites",
+                "django.contrib.redirects",
+                "django.contrib.contenttypes",
+                "elasticapm.contrib.django",
+                "tests.contrib.django.testapp",
             ],
-            ROOT_URLCONF='tests.contrib.django.testapp.urls',
+            ROOT_URLCONF="tests.contrib.django.testapp.urls",
             DEBUG=False,
             SITE_ID=1,
             BROKER_HOST="localhost",
@@ -78,28 +81,29 @@ def pytest_configure(config):
             CELERY_ALWAYS_EAGER=True,
             TEMPLATE_DEBUG=False,
             TEMPLATE_DIRS=[BASE_TEMPLATE_DIR],
-            ALLOWED_HOSTS=['*'],
+            ALLOWED_HOSTS=["*"],
             TEMPLATES=[
                 {
-                    'BACKEND': 'django.template.backends.django.DjangoTemplates',
-                    'DIRS': [BASE_TEMPLATE_DIR],
-                    'OPTIONS': {
-                        'context_processors': [
-                            'django.contrib.auth.context_processors.auth',
-                        ],
-                        'loaders': [
-                            'django.template.loaders.filesystem.Loader',
-                        ],
-                        'debug': False,
+                    "BACKEND": "django.template.backends.django.DjangoTemplates",
+                    "DIRS": [BASE_TEMPLATE_DIR],
+                    "OPTIONS": {
+                        "context_processors": ["django.contrib.auth.context_processors.auth"],
+                        "loaders": ["django.template.loaders.filesystem.Loader"],
+                        "debug": False,
                     },
-                },
-            ]
+                }
+            ],
+        )
+        settings_dict.update(
+            **middleware_setting(
+                django.VERSION,
+                [
+                    "django.contrib.sessions.middleware.SessionMiddleware",
+                    "django.contrib.auth.middleware.AuthenticationMiddleware",
+                    "django.contrib.messages.middleware.MessageMiddleware",
+                ],
+            )
         )
-        settings_dict.update(**middleware_setting(django.VERSION, [
-            'django.contrib.sessions.middleware.SessionMiddleware',
-            'django.contrib.auth.middleware.AuthenticationMiddleware',
-            'django.contrib.messages.middleware.MessageMiddleware',
-        ]))
         settings.configure(**settings_dict)
-        if hasattr(django, 'setup'):
+        if hasattr(django, "setup"):
             django.setup()

elasticapm/__init__.py

@@ -9,13 +9,12 @@
 :license: BSD, see LICENSE for more details.
 """
 
-__all__ = ('VERSION', 'Client')
+__all__ = ("VERSION", "Client")
 
 try:
-    VERSION = __import__('pkg_resources') \
-        .get_distribution('elastic-apm').version
+    VERSION = __import__("pkg_resources").get_distribution("elastic-apm").version
 except Exception as e:
-    VERSION = 'unknown'
+    VERSION = "unknown"
 
 from elasticapm.base import Client
 from elasticapm.conf import setup_logging  # noqa: F401