V4 insitute code formatting standard using Black (plotly#1626)

 - Formats the codebase using Black (https://black.readthedocs.io/en/stable/)
 - Updates codegen logic to use black instead of yapf for code formatting
 - Adds a pre-commit hook specification for running black prior to commit
 - Adds instructions to contributing.md for setting up pre-commit.
 - Adds a circleci test case to check that formatting is valid

Author: jonmmease

.circleci/config.yml

@@ -1,6 +1,19 @@
 version: 2
 
 jobs:
+  check-code-formatting:
+    docker:
+      - image: circleci/python:3.7-stretch-node-browsers
+
+    steps:
+      - checkout
+      - run:
+          name: Install black
+          command: 'sudo pip install black'
+      - run:
+          name: Check formatting with black
+          command: 'black --check .'
+
   # Core
   python-2.7-core:
     docker:
@@ -297,7 +310,7 @@ jobs:
       - checkout
       - run:
           name: Install tox
-          command: 'sudo pip install tox requests yapf pytz decorator retrying inflect'
+          command: 'sudo pip install tox requests black pytz decorator retrying inflect'
       - run:
           name: Update jupyterlab-plotly version
           command: 'cd packages/python/plotly; python setup.py updateplotlywidgetversion'
@@ -341,6 +354,9 @@ jobs:
 
 workflows:
   version: 2
+  code_formatting:
+    jobs:
+      - check-code-formatting
   dev_build:
     jobs:
       - plotlyjs_dev_build

.pre-commit-config.yaml

@@ -0,0 +1,6 @@
+repos:
+-   repo: https://github.com/ambv/black
+    rev: stable
+    hooks:
+    - id: black
+      language_version: python

contributing.md

@@ -64,6 +64,32 @@ Here's what you need to know: changes to any files inside the following director
 - `packages/python/chart-studio/chart_studio/plotly/chunked_requests`
 - `packages/python/plotly/plotly/matplotlylib/mplexporter`
 
+### Configure black code formatting
+This repo uses the [Black](https://black.readthedocs.io/en/stable/) code formatter,
+and the [pre-commit](https://pre-commit.com/) library to manage a git commit hook to
+run Black prior to each commit.  Both pre-commit and black are included in the
+`packages/python/plotly/optional-requirements.txt` file, so you should have them
+installed already if you've been following along.
+
+To enable the Black formatting git hook, run the following from within your virtual
+environment.
+
+```bash
+(plotly_dev) $ pre-commit install
+``` 
+
+Now, whenever you perform a commit, the Black formatter will run.  If the formatter
+makes no changes, then the commit will proceed.  But if the formatter does make changes,
+then the commit will abort.  To proceed, stage the files that the formatter
+modified and commit again.
+
+If you don't want to use `pre-commit`, then you can run black manually prior to making
+a PR as follows.
+
+```bash
+(plotly_dev) $ black .
+```
+
 ### Making a Development Branch
 
 Third, *don't* work in the `master` branch. As soon as you get your master branch ready, run:

packages/python/chart-studio/chart_studio/__init__.py

@@ -1,8 +1,2 @@
 from __future__ import absolute_import
-from chart_studio import (
-    plotly,
-    dashboard_objs,
-    grid_objs,
-    session,
-    tools,
-)
+from chart_studio import plotly, dashboard_objs, grid_objs, session, tools

packages/python/chart-studio/chart_studio/api/utils.py

@@ -12,11 +12,11 @@ def _to_native_string(string, encoding):
 
 
 def to_native_utf8_string(string):
-    return _to_native_string(string, 'utf-8')
+    return _to_native_string(string, "utf-8")
 
 
 def to_native_ascii_string(string):
-    return _to_native_string(string, 'ascii')
+    return _to_native_string(string, "ascii")
 
 
 def basic_auth(username, password):
@@ -31,11 +31,11 @@ def basic_auth(username, password):
 
     """
     if isinstance(username, str):
-        username = username.encode('latin1')
+        username = username.encode("latin1")
 
     if isinstance(password, str):
-        password = password.encode('latin1')
+        password = password.encode("latin1")
 
-    return 'Basic ' + to_native_ascii_string(
-        b64encode(b':'.join((username, password))).strip()
+    return "Basic " + to_native_ascii_string(
+        b64encode(b":".join((username, password))).strip()
     )

packages/python/chart-studio/chart_studio/api/v2/__init__.py

@@ -1,5 +1,14 @@
 from __future__ import absolute_import
 
-from chart_studio.api.v2 import (dash_apps, dashboards, files, folders, grids,
-                                 images, plot_schema, plots,
-                                 spectacle_presentations, users)
+from chart_studio.api.v2 import (
+    dash_apps,
+    dashboards,
+    files,
+    folders,
+    grids,
+    images,
+    plot_schema,
+    plots,
+    spectacle_presentations,
+    users,
+)

packages/python/chart-studio/chart_studio/api/v2/dash_apps.py

@@ -5,22 +5,22 @@
 
 from chart_studio.api.v2.utils import build_url, request
 
-RESOURCE = 'dash-apps'
+RESOURCE = "dash-apps"
 
 
 def create(body):
     """Create a dash app item."""
     url = build_url(RESOURCE)
-    return request('post', url, json=body)
+    return request("post", url, json=body)
 
 
 def retrieve(fid):
     """Retrieve a dash app from Plotly."""
     url = build_url(RESOURCE, id=fid)
-    return request('get', url)
+    return request("get", url)
 
 
 def update(fid, content):
     """Completely update the writable."""
     url = build_url(RESOURCE, id=fid)
-    return request('put', url, json=content)
+    return request("put", url, json=content)

packages/python/chart-studio/chart_studio/api/v2/dashboards.py

@@ -8,34 +8,34 @@
 
 from chart_studio.api.v2.utils import build_url, request
 
-RESOURCE = 'dashboards'
+RESOURCE = "dashboards"
 
 
 def create(body):
     """Create a dashboard."""
     url = build_url(RESOURCE)
-    return request('post', url, json=body)
+    return request("post", url, json=body)
 
 
 def list():
     """Returns the list of all users' dashboards."""
     url = build_url(RESOURCE)
-    return request('get', url)
+    return request("get", url)
 
 
 def retrieve(fid):
     """Retrieve a dashboard from Plotly."""
     url = build_url(RESOURCE, id=fid)
-    return request('get', url)
+    return request("get", url)
 
 
 def update(fid, content):
     """Completely update the writable."""
     url = build_url(RESOURCE, id=fid)
-    return request('put', url, json=content)
+    return request("put", url, json=content)
 
 
 def schema():
     """Retrieve the dashboard schema."""
-    url = build_url(RESOURCE, route='schema')
-    return request('get', url)
+    url = build_url(RESOURCE, route="schema")
+    return request("get", url)

packages/python/chart-studio/chart_studio/api/v2/files.py

@@ -3,7 +3,7 @@
 
 from chart_studio.api.v2.utils import build_url, make_params, request
 
-RESOURCE = 'files'
+RESOURCE = "files"
 
 
 def retrieve(fid, share_key=None):
@@ -17,7 +17,7 @@ def retrieve(fid, share_key=None):
     """
     url = build_url(RESOURCE, id=fid)
     params = make_params(share_key=share_key)
-    return request('get', url, params=params)
+    return request("get", url, params=params)
 
 
 def update(fid, body):
@@ -30,7 +30,7 @@ def update(fid, body):
 
     """
     url = build_url(RESOURCE, id=fid)
-    return request('put', url, json=body)
+    return request("put", url, json=body)
 
 
 def trash(fid):
@@ -41,8 +41,8 @@ def trash(fid):
     :returns: (requests.Response) Returns response directly from requests.
 
     """
-    url = build_url(RESOURCE, id=fid, route='trash')
-    return request('post', url)
+    url = build_url(RESOURCE, id=fid, route="trash")
+    return request("post", url)
 
 
 def restore(fid):
@@ -53,8 +53,8 @@ def restore(fid):
     :returns: (requests.Response) Returns response directly from requests.
 
     """
-    url = build_url(RESOURCE, id=fid, route='restore')
-    return request('post', url)
+    url = build_url(RESOURCE, id=fid, route="restore")
+    return request("post", url)
 
 
 def permanent_delete(fid):
@@ -65,8 +65,8 @@ def permanent_delete(fid):
     :returns: (requests.Response) Returns response directly from requests.
 
     """
-    url = build_url(RESOURCE, id=fid, route='permanent_delete')
-    return request('delete', url)
+    url = build_url(RESOURCE, id=fid, route="permanent_delete")
+    return request("delete", url)
 
 
 def lookup(path, parent=None, user=None, exists=None):
@@ -80,6 +80,6 @@ def lookup(path, parent=None, user=None, exists=None):
     :returns: (requests.Response) Returns response directly from requests.
 
     """
-    url = build_url(RESOURCE, route='lookup')
+    url = build_url(RESOURCE, route="lookup")
     params = make_params(path=path, parent=parent, user=user, exists=exists)
-    return request('get', url, params=params)
+    return request("get", url, params=params)

packages/python/chart-studio/chart_studio/api/v2/folders.py

@@ -3,7 +3,7 @@
 
 from chart_studio.api.v2.utils import build_url, make_params, request
 
-RESOURCE = 'folders'
+RESOURCE = "folders"
 
 
 def create(body):
@@ -15,7 +15,7 @@ def create(body):
 
     """
     url = build_url(RESOURCE)
-    return request('post', url, json=body)
+    return request("post", url, json=body)
 
 
 def retrieve(fid, share_key=None):
@@ -29,7 +29,7 @@ def retrieve(fid, share_key=None):
     """
     url = build_url(RESOURCE, id=fid)
     params = make_params(share_key=share_key)
-    return request('get', url, params=params)
+    return request("get", url, params=params)
 
 
 def update(fid, body):
@@ -42,7 +42,7 @@ def update(fid, body):
 
     """
     url = build_url(RESOURCE, id=fid)
-    return request('put', url, json=body)
+    return request("put", url, json=body)
 
 
 def trash(fid):
@@ -55,8 +55,8 @@ def trash(fid):
     :returns: (requests.Response) Returns response directly from requests.
 
     """
-    url = build_url(RESOURCE, id=fid, route='trash')
-    return request('post', url)
+    url = build_url(RESOURCE, id=fid, route="trash")
+    return request("post", url)
 
 
 def restore(fid):
@@ -69,8 +69,8 @@ def restore(fid):
     :returns: (requests.Response) Returns response directly from requests.
 
     """
-    url = build_url(RESOURCE, id=fid, route='restore')
-    return request('post', url)
+    url = build_url(RESOURCE, id=fid, route="restore")
+    return request("post", url)
 
 
 def permanent_delete(fid):
@@ -83,8 +83,8 @@ def permanent_delete(fid):
     :returns: (requests.Response) Returns response directly from requests.
 
     """
-    url = build_url(RESOURCE, id=fid, route='permanent_delete')
-    return request('delete', url)
+    url = build_url(RESOURCE, id=fid, route="permanent_delete")
+    return request("delete", url)
 
 
 def lookup(path, parent=None, user=None, exists=None):
@@ -98,6 +98,6 @@ def lookup(path, parent=None, user=None, exists=None):
     :returns: (requests.Response) Returns response directly from requests.
 
     """
-    url = build_url(RESOURCE, route='lookup')
+    url = build_url(RESOURCE, route="lookup")
     params = make_params(path=path, parent=parent, user=user, exists=exists)
-    return request('get', url, params=params)
+    return request("get", url, params=params)